Mechatronic Systems and Materials MSM – 2017

The 13th International Conference

Abstracts

Compiled by Justinas Gargasas

3 – 5 July, 2017 Vilnius, Lithuania The 13th International Conference “Mechatronic Systems and Materials (MSM - 2017)” Abstractsnof Papers for the 13th International Conference: “Mechatronic Systems and Materials (MSM – 2017)”. Vilnius, Lithuania, 03 – 05 July 2017. Compiled by Justinas Gargasas. Vilnius: Technika, 2017. 125p.

This book constitutes the abstracts of Papers presented for the 13th International Conference on Mechatronic Systems and Materials – MSM 2017, which is being held in Vilnius from 03 – 05 July 2017 and organized by Vilnius Gediminas technical university, Kaunas University of Technology, the Lithuanian Academy of Sciences, Opole University of Technology, Bialystok Technical University, the IFToMM National Committee of Lithuania. The aim of the conference is to provide an opportunity to share information and facilitate co-operation in mechatronics, new materials and dissemination of current research results in this multi-disciplinary field. The task of the Conference is not only to acquaint participants with the works of scientists from different countries, but to expand their collaboration in the future. The abstracts are printed without editing, but as presented by their authors.

For information write to: Vilnius Gediminas Technical University, Faculty of Mechanics, Organizing Committee of International Conference MSM-2017 Facuclty of Mechanics, J. Basanavičius str. 28, LT-03224, Vilnius, Lithuania http://www.msm2017.vgtu.lt/index.php/mechanika/index/pages/view/home2017; E-mail: [email protected]

eISBN 978-609-476-043-3

CONTENTS

APPLICATION OF SMART MATERIALS IN MECHATRONIC DEVICES ...... 8 Andrzej Milecki THROW DOWN A CHALLENGE TO THE PIEZO-MECHATRONIC SYSTEMS DESIGN ...... 19 Borodinas Sergejus DYNAMIC BEHAVIOUR OF GFRP FOOTBRIDGE MODEL ...... 25 Darius Bacinskas, Arturas Kilikevicius, Arvydas Rimkus, Deividas Rumsys, Adas Meskenas REDUCTION VIBRATION OF SYNTHESIZED DRIVING SYSTEMS TO THE REQUIRED VALUES OF AMPLITUDES ...... 26 Dzitkowski Tomasz, Dymarek Andrzej, Brodny Jarosław PRINCIPLES OF DESIGN AND FORMATION OF A SELF-SUPPORTING SKELETON IN CONSTRUCTING BUILDINGS OF COMPLEX GEOMETRIC SHAPES WITH THE USE OF SHOTCRETE TECHNOLOGY ...... 28 Sergey Bugayevskiy, Vladimir Babaev, Valery Shmukler, Vladymir Gerasymenko, Andreі Zadorozhny, Gintas Viselga INVESTIGATION OF OIL WHIP AND WHIRL INFLUENCE ROTOR SYSTEM WITH HYDRODYNAMIC ADAPTIVE SEGMENTAL BEARING OF WORKING STABILITY ...... 29 Audrius Čereška CONTROL OF THE 6-AXIS ROBOT USING A BRAIN-COMPUTER INTERFACE BASED ON STEADY STATE VISUALLY EVOKED POTENTIAL (SSVEP) ...... 31 Arkadiusz Kubacki, Andrzej Milecki CALCULATION POSSIBILITIES OF 3D SURFACE ROUGHNESS PARAMETERS ...... 33 Natalija Bulaha, Janis Rudzitis APPLICATION OF THE FRACTIONAL ORDER CONTROLLER IN ELECTROHYDRAULIC SERVO DRIVE ...... 35 Dominik Rybarczyk, Andrzej Milecki STRUCTURE PARAMETERS OF RUBBER MODIFIED IN POLYETHYLENE OXIDE ...... 37 Elena P. Uss, Andrei V. Kasperovich, Zhanna S. Shashok INVESTIGATION OF ELASTIC PROPERTIES OF PRINTS ...... 38 Simona Grigaliuniene, Vytautas Turla, Jonas Sidaravicius, Paulius Ragauskas, Arturas Kilikevicius PRINCIPLES OF SEARCHING FOR THE OPTIMAL DESIGN SOLUTION OF THE LONGITUDINAL HIGHWAY PROFILE ...... 40 Nadiejda Pavlenko, Gintas Viselga ARMATURE TYPE INFLUENCE FOR ELECTROMAGNETIC LAUNCHER RAIL ...... 41 Justinas Račkauskas,Rimantas Kačianauskas, Markus Schneider THE INVESTIGATION OF IRON – BASED CORED WIRES FOR THERMAL ARC SPRAYING ...... 43 Justinas Gargasas, Irmantas Gedzevičius, Gintas Viselga, Ina Tetsman, Giedrius Balčiūnas, Vytautas Turla, Hanna Pokhmurska

INCIPIENT BEARING FAULT DIAGNOSIS USING WPT AND ANN INCLUDING PARAMETER OPTIMIZATION ...... 45 María Jesús Gómez, Eduardo Corral, Cristina Castejón, Juan Carlos García-Prada ANALYSIS AND NUMERICAL MODELING OF BROKEN AXLE CONSTRUCTION ...... 47 Živilė Čepukė, Vitalijus Rudzinskas, Olegas Černašėjus ESTIMATION OF DAMPING RATIOS OF PEDESTRIAN BRIDGE BY OPERATIONAL MODAL ANALYSIS METHOD ...... 48 Darius Bacinskas, Arturas Kilikevicius FINITE ELEMENT ANALYSIS OF 3D PRINTED SCAFFOLDS ...... 49 Deividas Mizeras, Algirdas Vaclovas Valiulis, Andžela Šešok, Artūras Kilikevičius, Justinas Gargasas LOW CYCLE FATIGUE OF ALUMINUM ALLOYS UNDER STRAIN-CONTROLED LOADING ..... 51 Kurek Andrzej, Koziarska Justyna, Łagoda Tadeusz DYNAMIC DIAGNOSTICS INVESTIGATIONS OF STEEL WIRE ROPE CONDITION EVALUATION ...... 52 Audrius Čereška, Vytautas Bučinskas, Ernestas Šutinys A SIMPLE APPROACH TO MECHANICAL MODELING OF SINGLE MITRAL VALVE CHORDA ...... 54 Gediminas Gaidulis, Rimantas Kačianauskas, Oleksandr Hubanov, Audrius Aidietis MODAL ANALYSIS OF THE OPTICAL TABLE LEVITATING ON MAGNETIC SUPPORTS ...... 56 Andrius Gedvila, Artūras Kilikevičius, Vadim Mokšin INVESTIGATION ON THE EFFICIENCY OF USING TECHNICAL MEANS FOR MULCHING POTATO SOILS ...... 58 Gintas Viselga, Mindaugas Jurevičius, Justinas Gargasas, Ina Tetsman, Vytautas Turla, Algirdas Jasinskas, Aneta Marczuk, Edmund Kaminski, Evgeniya Ugnenko MAGNETORHEOLOGICAL MODELLING OF OSCILLATING ENERGY HARVESTER FOR LOW FREQUENCY APPLICATIONS ...... 59 Sigitas Petkevičius, Vytautas Bučinskas, Andrius Dzedzickis, Darius Viržonis, Ernestas Šutinys, Inga Morkvėnaitė-Vilkončienė KINEMATICS AND DYNAMICS OF THE QUASI-PASSIVE ROBOT WALKING “PASIQUAD” ...... 61 Eduardo Corral, Jesús Meneses, María Jesús Gómez Garcia, Juan Carlos García-Prada RESEARCH OF CU-NB MICROCOMPOSITE WIRES WELDED JOINTS ...... 62 Gediminas Mikalauskas, Nikolaj Višniakov, Raimonda Lukauskaitė, Jelena Škamat INVESTIGATION OF ELASTIC PAPER PROPERTIES USING MODAL ANALYSIS ...... 64 Artūras Kilikevičius, Nikolaj Šešok, Igor Iljin, Rimantas Stonkus STRUCTURAL CHARACTERISTICS OF ZRC/NI-UDD COATINGS DEPOSITED ON A TUNGSTEN CARBIDE CUTTING TOOL ...... 65 V.V. Chayeuski, V.V. Zhylinski, O. Černašėjus, N. Višniakov, R. Lukauskaitė DESIGN AND NUMERICAL ANALYSIS OF THE ROBOT END–EFFECTOR IN THE FORM OF HUMAN HAND ...... 67 Sławomir Grycuk, Roman Trochimczuk, Iwona Gruszczyńska

INFLUENCE OF THE SPECIMEN’S MATERIAL AND SHAPE ON BEHAVIOR OF THE FATIGUE TEST STAND MZGS100 ...... 69 Lagoda Tadeusz, Marta Kurek, Robak Grzegorz, Pawliczek Roland NUMERICAL SIMULATION INTERACTION OF AEROSOL PARTICULUTE AGGLOMERATES IN ACOUSTIC FIELD ...... 71 Darius Vainorius, Rimantas Kačianauskas , Algirdas Maknickas SIMULATION OF TEMPERATURE AND THERMAL DEFORMATION FIELDS OF MULTILAYERED STRUCTURE ...... 72 Remigijus Guobys, Vladas Vekteris, Vadim Mokšin, Gintas Viselga A COMPARATIVE STUDY OF POLYDIMETHYLSILOXANE (PDMS) FOR PREDICTION OF HYPERELASTIC PROPERTIES: APPLICATION TO SILICONE-RUBBER AND SOFT TISSUES ... 74 Artūras Kilikevičius, Darius Vainorius, Algirdas Maknickas INVESTIGATION OF THE INFLUENCE OF ACOUSTIC FIELD ON VAPOR PRECIPITATION OVER PLATING BATH ...... 75 Ina Tetsman, Vladas Vekteris, Vadim Mokšin SIMULATION AND TENSILE TESTING OF TOPOLOGICALLY OPTIMIZED CERVICAL IMPLANTS MADE BY ADDITIVE MANUFACTURING IS COMPARABLE ...... 77 Schnitzer Marek, Kula Tomáš, Hudák Radovan, Bocko Jozef, Živčák Jozef, Zubko Pavol, Karásek Michal Szedlák Peter INVESTIGATION OF ACOUSTIC GENERATORS ...... 80 Vladas Vekteris, Darius Ozarovskis, Vadim Mokšin FUZZY CONTROLLERS IN FIELD ORIENTATION CONTROL SYSTEM OF SIX-PHASE INDUCTION MOTOR ...... 82 Roma Rinkevičienė, Zita Savickienė, Saulius Lisauskas, Andrius Petrovas, Donatas Uznys, Aurelijus Pitrėnas, Alvydas Šlepikas FAULT DIAGNOSTICS OF ROLLING ELEMENT BEARINGS OF ROTOR SYSTEMS EQUIPPED WITH VIBRATION DAMPERS ...... 84 Vladas Vekteris, Andrius Trumpa, Vytautas Turla, Vadim Mokšin, Gintas Viselga INVESTIGATION OF POLISHING CHARACTERISTICS FOR ASPHERICAL LENSES MANUFACTURING ...... 86 Nerijus Kadzevičius, Ieva Švagždytė, Justinas Gargasas, Mindaugas Jurevičius, Artūras Kilikevičius INVESTIGATION OF FLOW GENERATED IN THE EJECTOR ...... 88 Vladas Vekteris, Andrius Styra, Vadim Mokšin, Gintas Viselga, Mindaugas Jurevičius, Ina Tetsman DESIGNING AND OPTIMISATION OF FIXING SYSTEMS IN A WELDING TOOL OF INDUSTRIAL ROBOT ...... 90 W. J. Klimasara, M. Pachuta, Z. Pilat, M. Słowikowski MULTI – FREQUENCY PIEZOELECTRIC ENERGY HARVESTER BASED ON RHOMB TYPE CANTILEVER ARRAY ...... 91 Andrius Čeponis, Dalius Mažeika ANALYSIS OF INFLUENCE OF TYPE OF SOIL ON LONGITUDINAL MOTION OF LIGHTWEIGHT WHEELED MOBILE ROBOT – SIMULATION RESEARCH ...... 92 Maciej Trojnacki, Przemysław Dąbek 4

RESEARCH OF MODIFIED ATOMIC FORCE MICROSCOPE SENSOR USING IMPROVED 3D MODEL ...... 93 Vytautas Bučinskas, Andrius Dzedzickis, Artūras Ulčinas, Inga Morkvėnaitė-Vilkončienė, Sigitas Petkevičius, Ryszard Jabłoński DIRECT MEASUREMENT OF SIX-PHASE INDUCTION DRIVE MAGNETIC FLUX IN THE AIR GAP ...... 94 Donatas Uznys, Dominykas Beištaras, Aurelijus Pitrėnas VEGETABLE HARVEST ASSESSMENT BY ANALYSIS OF VIBRATIONS ...... 95 Eugenijus Jurkonis, Rimantas Stonkus, Andrius Dzedzickis DEVELOPMENT OF MULTIFUNCTION ELECTRIC ARC COATINGS OBTAINED BY SPRAYING OF CORED WIRES ON THE BASE OF FECRB-AL AND FE-CR-C-AL ...... 96 Mykhajlo Student, Justinas Gargasas, Irmantas Gedzevičius, Hanna Pokhmurska, Oleksandra Student, Lyudmyla Dzyubyk, Volodymyr Gvozdeckii BUSHING SHAFT ASSEMBLY WEAR CALCULATION PRINCIPLES ...... 98 Karlis Berzins, Janis Rudzitis THE CRACK SURFACE TOPOGRAPHY OF STRUCTURAL MATERIALS ...... 100 Wojciech Macek, Tomasz Wołczański, Krystyna Rajczyk, Zbigniew Marciniak, Grzegorz Garbacz STUDIES ON THE EFFECTS OF THE GAS COMPOSITION DURING DEPOSITION OF DLC-FILMS BY PACVD...... 103 Gerda Vaitkūnaitė, Daniel Heim, Christian Forsich, Irmantas Gedzevicius, Justinas Gargasas THE POWER OF ARTIFICIAL INTELLIGENCE IN MEDICAL IMAGE ANALYSIS...... 104 Prof. Aliaa Youssif IMPEDANCE CONTROL METHOD FOR EXPERIMENTAL SIMULATION OF TRAFFIC VIBRATIONS IN MONOLITHIC BRIDGE WIDENING ...... 105 Pui-Lam Ng, Albert Kwok-Hung Kwan QUANTITATIVE ASSESSMENT OF DANCE THERAPY INFLUENCE ON UPPER LIMB BIOMECHANICS FOR A PEOPLE WITH PARKINSON’S DISEASE ...... 106 Donatas Lukšys, Dalius Jatužis, Rūta Kaladytė – Lokominienė, Ramunė Bunevičiūtė, Gabrielė Mickutė, Alvydas Juocevičius, Julius Griškevičius METHODS FOR MEASURING THE FRICTION COEFFICIENT OF THE ROAD SURFACE ...... 108 Elena Perova, Evgeniya Ugnenko, Olga Gubareva, Gintas Viselga INVESTIGATION OF PARTICLES COAGULATION WITH TWO METHODS INFLUENCING THE ACOUSTIC FIELD ...... 109 Audrius Čereška, Irina Grinbergienė ANALYSIS OF VIBRATION EFFECTS ON THE COMFORT OF LOW FLOOR BUS USERS BY OSCILLATORY MODE ...... 111 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Nikolaj Šešok, Igor Iljin EXPERIMENTAL RESEARCH OF LOW FLOOR BUS ...... 112 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Nikolaj Šešok, Igor Iljin RESEARCH OF WASTEWATER TREATMENT WITH USED TIRES SHREDS ...... 113 Ina Tetsman, Kristina Baziene , Justinas Gargasas, Gintas Viselga 5

EXPERIMENTAL RESEARCH OF GRAVIMETRIC SYSTEM ...... 114 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Romuald Obuchovski INVESTIGATION OF ROLLER INTERACTIONS WITH STEEL TAPE...... 115 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Sergejus Borodinas EXPERIMENTAL INVESTIGATION OF FRICTION TRANSITION ON LATERAL VIBRATION OF STEEL TAPES ...... 116 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Sergejus Borodinas INFLUENCE OF HEAT TREATMENT ON MICROSTRUCTURAL EVOLUTION AND MECHANICAL CHARACTERISTICS OF THE AL-6061 ALLOY ...... 117 Hanae Chabba, Irmantas Gedzevičius, Justinas Gargasas, Driss Dafir INVESTIGATION OF DYNAMIC IMPACT OF FIREARM WITH SUPPRESSOR ...... 118 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Sergejus Borodinas MIXED MODE I/II FRACTURE UNDER DYNAMIC LOADING FRACTURE ...... 119 Algis Pakalnis, Petras Šadreika, Antanas Žiliukas EXPERIMENTAL ANALYSIS OF NOISE AND VIBRATION OF A DIESEL ENGINE ...... 120 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Darius Vainorius, Jonas Matijošius, Alfredas Rimkus, Akos Bereczky DETERMINING SNOW CAPACITY OF SNOW PROTECTION FACILITIES ON ROADS IN THE MOUNTAINOUS AREA ...... 121 Оlga Тymchenko, Gintas Viselga STATISTICAL ANALYSIS OF COMPRESSION IGNITION ENGINE PARAMETERS FUELLED WITH VARIOUS BIODIESELS ...... 122 Artūras Kilikevičius, Antanas Fursenko, Kristina Kilikevičienė, Darius Vainorius, Jonas Matijošius, Alfredas Rimkus, Akos Bereczky PROVIDING A GIVEN POSITION MULTIPLE SUPPORTED STRUCTURES STRUCTURES BEAM ...... 123 Lyudmyla Dzyubyk, Hanna Pokhmurska, Andriy Dzyubyk SOME FEATURES OF THE RHEOLOGICAL PROPERTIES OF COMPOSITE MATERIALS WITH FUNCTIONALIZED CARBON NANOADDITIVES ...... 124 Zhanna S. Shashok, Konstantin V. Vishnevskii, Nikolay R. Prokopchuk DINAMICAL RESEARCH OF PHOTOVOLTIC SYSTEM ...... 125 Vytautas Makarskas, Mindaugas Jurevičius, Artūras Kilikevičius

APPLICATION OF SMART MATERIALS IN MECHATRONIC DEVICES

Andrzej Milecki* Faculty of Mechanical Engineering and Management, Division of Mechatronics Devices, Poznan University of Technology, Piotrowo 3, 61-138 Poznań E-mail: [email protected]

Keywords: smart materials, piezo elements, shape memory alloys, magnetic shape memory alloys

Abstract

In the introduction a short history of the term Mechatronics and its different definitions illustrated by figures, are presented. Then the main investigations area of Mechatronics is sketched. The special attention is given to application of new, so called, smart or even intelligent materials in mechatronic devices. The main goal of these investigations is to achieve mechatronic devices smart in mechanics, intelligent in communication and control with the user. In the paper the basic properties of such smart materials like piezoelectric crystals and magnetic shape memory alloys are presented. Then the investigations results of developed in Division of Mechatronic Devices at Poznan University of Technology (PUT) elements with these smart materials, are described. In the paper chosen research results, focused on the used smart materials parameters improvement, are included. The main goal of these research is focused on hysteresis compensation. Practical examples of mechatronic devices in which mentioned above materials are used are also presented. The paper finishes with conclusion, in which several remarks related to the possible future mechatronics directions development are sketched.

Introduction The term mechatronics was originated by senior engineer Tetsura Mori in 1969 in Japanese Corporation Yaskawa Electric, that produced in that time mechanical equipment and started to use of electronic elements in them. This company wanted to introduce a technical term to name that novelty. Therefore Mori combined the two technical words ‘mechanical’ and ‘electronics’ and created the new one: mechatronics. The Company has applied to make this word a registered brand and has got the rights in 1972 [1]. Since that time the meaning of mechatronics has broadened and it is now commonly used to characterize almost every application of electronics into mechanical devices. A number of definitions has been proposed in the literature for the wider concept of mechatronics. In most cases, these definitions emphasize mechatronics as the synergistic integration of mechanical engineering with electronics and intelligent computer control in the design and manufacture of products and processes. Nowadays, the application of so called smart materials in mechatronic devices enabled to create new sensors and new active or semi-active actuators. In this paper such smart materials like Piezo Actuators (PA) and Shape Memory Alloys (SMA) are shortly presented. Then their main non-linearity as hysteresis is described. The commonly used hysteresis models are presented and used in open loop control system. Chosen simulation and laboratory investigations results are included. Finally the application of mentioned above materials are shown. Their behaviors are illustrated using research results conducted in Division of Mechatronic Devices at Poznan University of Technology. The goal of the paper is to show the possible future potential in application of new advanced, sometimes called also as intelligent materials in mechatronic devices. There are still open areas for creation of a scientific background, tools and methods for design of mechatronic devices.

Mechatronics and its Definitions Since early 1990s several conferences related to mechatronics have been organized like for example: the biennial Mechatronics Forum Conferences held since 1989 (Lancaster UK), 1990, 1992 (Cambridge UK), 1994 (Hungary), 1996 (Minho, Portugal), 1998 (Skövde, Sweden), 2000 (Atlanta, USA), 2002 (Twente, The Netherlands), 2004 (Ankara, Turkey), 2006 ( Malvern, USA), 2008 (Limerick, Ireland), 2010 (Zurich, Switzerland) or IEEE International Conferences on Advanced Intelligent Mechatronics (AIM), which were held since 1999 till now every second or every year, and finally International Conference Mechatronic Systems and Materials - MSM which is organized every year since 2005 in Poland (Białystok, Opole) or in Lithuania (Kaunas, Vilnus). There are several books focusing on mechatronics, for example [2, 3, 4, 5]. One of the last issued is [6], which illustrates the mechatronics concepts and application from auto-focus cameras to car engine management systems, and from state-of-the-art robots to the humble washing machine, where Mechatronics has a hand in them all. There are two important journals, focused on Mechatronics i.e. Mechatronics [7] and IEEE/ASME Transactions on Mechatronics [8]. The first one provides rapid publication of topical papers featuring practical developments in mechatronics and the second one encompasses all practical aspects of the theory and methods of mechatronics, the synergetic integration of mechanical engineering with electronic and intelligent computer control in the design and manufacture of industrial products and processes.

Electromechanics

Mechanical Eng. Electrical Eng. and Machines and Electronics Smart Materials, Sensors, Actuators

CAD/CAx Microcontrollers FEM MECHATRONICS and PLC

Modelling, Simulation HIL, RP Computer Control Optimization, Systems Science Artificial Intelligence

Fig. 1. Graphical definition of „Mechatronics“

Over the last almost 50 years several definitions of mechatronics, either as a text, logo or pictures have been proposed. On a web page [9] one may found list of over 20 definitions of mechatronics, which conclude that mechatronics is about the integration of the core disciplines of mechanical engineering (mechanical elements, machines, robot arms etc.), electronics (microelectronics, power electronics, sensors and actuators) and information technology (control and automation, software engineering, artificial intelligence). Probably the most popular definition is given on a web page of a Mechatronics journal: “Mechatronics is the synergistic combination of precision mechanical engineering, electronic control and systems thinking in the design of products and manufacturing processes. It relates to the design of systems, devices and products aimed at achieving an optimal balance between basic mechanical structure and its overall control”. Nowadays, the aim of mechatronics is to improve the functioning of systems and devices by transforming them into one automatic and intelligent system. The term mechatronics is also described by many graphics and schemes as shown in Fig. 1. In the design of mechatronic products, interrelations play an important role. This is because the mechanical 9

solution influences the electronic system and the control system has influence on electronic and mechanical parts. In this way simultaneous engineering has to take place, with the goal of designing an integrated system and also creating synergetic effects.

Smart Materials This paper is intended to presents a short overview of currently used so called Smart (or Active) Materials and their applications. A smart system is defined as a nonbiological phisycal system which combines the smart materials with advanced control system. It is composed of sensing, processing and actuating subsystems, which uses the properties of smart materials to achieve high performances. Thus, a smart system can be also regarded as mechatronic device. Smart materials are a subset of such a devise. The definition of these materials can be found in [10] as: “Smart materials are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields”. This paper is focused only on a class of materials that exhibit the ability to change their mechanical parameters as a response on electrical signals. Smart materials can be divided into active and semi-active. The first ones are able to transform input signals (electrical energy) into force and motion (mechanical energy). The second ones can only change their inner properties like viscosity or stiffness. The “SMA Smart Materials and Surfaces - SMS – Conference” [11] recognized among others, following smart materials: Multifunctional, Shape Memory, Multiferroic and Magnetoelectric, Inorganic Luminescent, Electro-active Polymers, Biomaterials, Intelligent Textiles, Graphene and Other Emerging 2D-layered Nanomaterials. Most of these materials are dynamic in nature with step respond time constant in the range of a few milliseconds. Advancements in smart materials science, resulted in the development of materials which parameters may change in broaden range opening new specific applications, which are previously not possible. Smart material market is expected to be about $73 billion by 2022, having Compound Annual Growth Rate (CAGR) of 14.9%. The oldest smart material is the piezoelectric crystal, which may act as both sensor and actuator. In the first case it produces an electric charge when mechanically stressed and in the second case, a strain when an electric field is applied across them. So, it converts mechanical energy into electrical energy or vice versa. Piezoelectric actuators are attractive due to their fast response and big output forces. These actuators have been widely used so far, in common rail direct fuel injection system for petrol and diesel engines, but they can be also applied in small robots as smart drives, in positioning devices etc. Other smart materials are magnetic active ones. One of them is magnetostrictive material, like Terfenol-D. Magnetostriction is the change in shape of materials under the influence of an external magnetic field, as a result of the rotation of small magnetic domains. Both, piezo and magnetostrictive elements are characterized by high dynamics, but their deformations are rather low i.e. not more than tens of micrometers [12]. One of interesting application of piezo elements is their use in pneumatic or hydraulic servo-valves, where very precise torque motor is replaced by piezo stacks or by piezo bender actuators [13, 14]. The next smart materials are shape memory alloys (SMAs), which change their shape as response of temperature change. Similar materials are magnetic shape memory alloys (MSMAs), which change their properties i.e. dimensions in presence of external magnetic field. Graphene is relatively a new material, with interesting mechanical and electronic properties that may be used in a broad range of mechatronic devices. There is high potential of graphene in high-speed analog electronics because of its high carrier mobility. However, the broaden applications of smart material in practice encounters obstacles, which are small output signal like displacement from one side, and non-linearity - mostly hysteresis, from the other side, which must be eliminated or compensated, to achieve satisfactory application results.

Piezo Actuators and their Applications Piezo crystals are able to change electrical a) F l signals into mechanical ones. The main advantage of piezo U transducers is their high maximum frequency, which can reach even a few kHz. Two main types of piezo b) transformers are available on the market: stack and bending (Fig. 2). The first of them is able to +U l produce displacement of about 0,1% of its length i.e. in the range of nm to a few of µm and forces till a few kN. Bending transformers can in turn -U F generate much bigger displacements, reaching fractions of mm, but their output forces are not bigger than a few N. A Fig. 2. Piezoelectric actuators: a) stack, b) bending stack actuator is composed of several piezoelectric layers, placed one on the other. A bending actuator consist of two or three layers with greater length than the stacked type actuator. A special case is bimorph actuator, which consists of two identical piezo-plates connected parallel. The application of an electric field across these two layers causes one layer to expand while the other one to contracts, which results in a bending deformation. Nowadays piezo actuators are used especially in a wide variety of positioning devices i.e. in mechatronic devices. There is also possible to use bending actuators in electrohydraulic servo valves instead of torque motor. Unfortunately in such applications the piezo actuator suffers from hysteresis and creep between the input voltage and resulting displacements.

Piezo Actuator Uin 1 Control Amplifier

2 3 x m 4 p p Position 0  0 m measurement p p p 2 1 T 0 T

A B Fig. 3. Servo valve with piezo actuator Fig. 4. Photo of the servo valve with piezo actuator In the Institute of Mechanical Engineering at Poznan University of Technology an electrohydraulic servo valve controlled by piezo bender actuator have been designed and investigated. In presented in Fig. 3 solution, the torque motor was replaced by piezo bending actuator. Its plate was acting as a flapper (1) placed between two nozzles (2) and created the first stage of the valve, which controls the displacement of the spool (3). To obtain the feedback the application of displacement measure transducer type LVDT (4) is used. Its output signal (spool position) is compared to the assumed one and the control amplifier produces the voltage to the piezo element. In the valve the piezo bender transducer type PL 112.11 is applied [15]. It is characterized by displacement equal to ±0,08 mm (± 20%) after putting the maximum voltage equal to ±30 V. It produces the maximum output force equal to ±2 N. In produced

nowadays servo valves, torque motors with maximum torque from 20 to 50 mNm are applied. So, the force generated by piezo actuator is sufficient for its application in a valve.

xsuw [mm] y [µm] 6MPa (k=4) 30 0,2 20 10V 0,1 10 6V 12MPa (k=3) 18MPa (k=2.5) U [V] Uster [V] 0 0 -12 -8 -4 0 4 8 12 -8 -6 -4 -2 0 2 4 6 8 -10 -0,1 -20 -0,2 -30 -40  Fig. 5. Characteristic of piezo actuator type PL 112.11 Fig. 6. Characteristic of servo valve spool with PID

In Fig. 4 the recorded static characteristics of used piezo actuator are shown. On the actuator’s input the sinusoidal voltage signal with frequency 1 Hz which amplitude increased linearly is given and an output displacement is measured. Aa a result, a number of hysteresis loops are obtained (Fig. 5). To the control of the servo valve the system developed using PC with Matlab-Simulink and dSpace modue is used, which is connected to the LVDT (input) and to the piezo actuator amplifier (output). The controller type PID is implemented in Simulink. The valve spool displacements obtained in experiment are shown in Fig. 6. Thanks to the usage of feedback loop and PID controller the piezo actuator hysteresis is significantly reduced.

0,04

0,03

0,02

0,01

0 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 100 120 140 160 180 200 220

-0,01 Displacement Displacement [mm]

-0,02

-0,03

-0,04 Voltage [V] 20 [V] 40 [V] 60 [V] 80 [V] 100 [V] 120 [V] 140 [V] 160 [V] 180 [V] 200 [V] Fig. 7. Scheme of the test rig Fig. 8. The results of displacement for supply voltage for 3Hz sinus input signal with different amplitudes The piezo tube design has unique features comparing to others piezoelectric actuators – it allows to radial and axial contraction. These actuators are used as transducers in scanning tunnelling microscopy and scanning probe microscopies. The control system used at PUT to drive this piezo, worked under control of Matlab-Simulink and dSPACE with DS2201 ADC/DAC cards is shown in Fig. 7. Matlab- Simulink was used to set generator signal, record measured data and to implement the PID regulator. The system worked under real time mode using Control Desk dSPACE software. All Simulink model parameters can be changed continuously. The piezo displacement was measured by Fiberoptic Sensor. In the presented here research only two outer opposite electrodes are energized, while the remaining electrodes are connected to ground. The fifth electrode located on the inner side of the tube is used as common ground. The geometrical parameters of the tube are: length l = 40 mm, outer diameter do = 3.2 mm, inner diameter di = 2.2 mm. The operating voltage was ± 250 V. The displacement of the free end of the tube is measured in response to different voltage values and the result is shown in Fig 8. The 12

investigated actuator exhibits a symmetric hysteresis of approximately 20% – the ratio of the extreme difference in the displacement for 0 V, to the maximum displacement.

Magnetic Shape Memory Alloys investigations Shape memory alloys (SMA) change their dimensions according to the temperature. In comparison to other groups of smart materials, SMAs are characterised by large deformation. Unfortunately, the time of these deformation is long and the time constant of their step responses equals a few seconds. These materials find application in bi-stable safety valves, which open or close automatically when the temperature rises or lowers. A review of recent research and the practical applications of SMAs actuators are described in paper [16]. The special type of SMAs are magnetic shape

memory alloys (MSMAs), which change their dimensions spring

F in presence of external magnetic field. They can generate force and repeatable strains up to 6% of their dimensions in Magnetic response to externally applied magnetic field. MSMAs field V1 dynamic response is expressed in milliseconds, which is V2 comparable with magnetostrictive materials [17]. They can Compresive generate strains up to 1000 µm. Magnetic shape memory force effect is a result of cells reorientation in magnetic field in H a Rotation of cells with specially prepared crystal lattice. The MSMA material c magnetic field lines c consists of cells of cuboidal shape which has two long sides a (a) and one short side (c). In magnetic field the shapes Fig. 9. Principle of MSMA operation arrangement in MSMAs is mainly caused by their magnetic anisotropy. MSMAs have two martensitic phases (V2) and (V1). Operating principle and reorientation of MSMA cells is illustrated in Fig. 9. The increase of magnetic field strength causes reorientation of the cells in MSMA in such a way, that one longer side (a) of cells is located perpendicular and the second longer side is located parallel to the magnetic field lines (see Fig 9). As a result the probe lengthens in direction perpendicular to magnetic field lines. When the magnetic field strength decreases the MSMA structure transforms without changing geometrical dimensions from phase (V1) to phase (V2) and if a mechanical force is applied in this phase, the cells are reoriented in such a way that their shorter side (c) is located in parallel direction to this force. As a result, the sample changes to phase (V2).

Displacement sensor 1200 PC with Control Desk 1000

Laboratory programable 800 DC power supply source 600 Current control 400

Voltage control MSMA DAC

Displacement(µm) 200 dSPACE Current measurement MSMA 0

ADC Voltage measurement actuator 0 0.5 1 1.5 2 2.5 3 Current (A) Fig. 10. Scheme of the test for MSMA actuator investigation Fig. 11. Static characteristic of MSMA actuator

At Poznan University of Technology magnetic shape memory alloy sample (3x10x32 mm) is investigated. The scheme of the test stand is shown in Fig. 10. This is so-called spring returned mode, where extension is controlled by current flow through coils, but the return of the probe to the non- supplying mode (martensitic) is made by the spring. The current flow in the coils is the source of magneto motive force. Such kind of magnetic circuit needs more complex analysis during designing process, because relative magnetic permeability of the MSMA probe changes with its elongation in magnetic field. Proper placement of MSMAs sample in magnetic core ensures that magnetic flux passes perpendicular to generated movement. Disadvantage of this solution is the necessity of pre-stressing of the spring, which decreases maximum force generated by MSMAs and causes a need for accurate calibration. Also placement of spring above actuator increases its size. In the tests in order to achieve maximum elongation, the excitation coils current (connected in parallel) was equal to 3 A. Magnetic core is made of low carbon soft magnetic steel, which after annealing is distinguished by very low magnetization hysteresis in magnetic core, which is crucial regarding to output characteristics of MSMA actuator. In the test stand a displacement measuring system, which was MicroEpsilon triangular laser sensor (ILD-1700-10) is used. Application of positioning stages with regulation screw provided precision mictro-adjustment of the MSMA actuator. DSpace system was used for data acquisition and control tasks, made in cooperation with Matlab/Simulink and Control Desk software. Coils in actuator were energized by programmable DC power supply (max: 32 VDC, 10 A). The investigations result is presented in Fig. 11, where the static characteristic of MSMA actuator is shown. In this characteristic the wide saturated hysteresis is visible.

Hysteresis Compensation The presented above investigation results showed that every smart material is characterized by hysteresis, which significantly worsens the positioning accuracy. Therefore this hysteresis must be compensated. The commonly used solutions to reduce the hysteresis is the application of inversed hysteresis model [18, 19]. In order to obtain the inversed model, the normal hysteresis model must be developed. The hysteresis modeling began in 1935, where Preisach proposed a mathematical model based on physical mechanisms of magnetisation. An approach to the Preisach model (PM) is described in [20], where the phenomenological nature and mathematical generality of the PM and its basic properties are described. The PM approximates the hysteresis behavior by using the double integral operation. The model can be applied for elements, which can be experimentally identified. The PM adds an infinite set of elementary hysteresis operators γαβ, represented by a rectangular loop and characterized by parameters α and β. Each of these operators can be on the input-output plane, where number α corresponds to “up” and β to “down” of switching input values. These elementary hysteresis operators are similar to ordinary electric switch with hysteresis, but their output may only be assumed as +1 and –1 values. Krasnoselskii represented PM in a pure mathematical form. In the revised model an arbitrary weight function µ(α, β) is connected with the set of γαβ operators. The Preisach–Krasnoselskii (PK) model can be described by equation:

y  (, ) vd d   (1) µ(α,β)   γ αβ µ(α,β) v y γαβ + The block scheme of the PK model is shown in Fig. 12. At PUT several investigations on hysteresis modeling have been made [21, 22, 23]. So far, the best results are γαβ obtained using generalized Prandtl-Ishlinskii model µ(α,β) (GPIM). Significant advantage of this model is the possibility to customize of switch-like PM hysteresis Fig. 12. Block diagram of PK model (1) operator to describe accurately the shape of modeled hysteresis. In GPIM these operators are called “play operator” Gr (Fig. 13). This operator in ti step is expressed by equation [24, 25]

max l (ti )  zs , w(ti )  vti   vti1   (2) Gr v(ti )  min r (ti )  zs , w(ti )  vti   vti1    w(ti ),  vti   vti1  Due to the shape of major and minor hysteresis loops in magnetic shape z memory alloys, hyperbolic tangent functions are chosen for modeling process

γr γl  l (t)  a0 tanha1v(t)  a2  a3 (3) ζ2 ζ1 v  r (t)  b0 tanhb1v(t)  b2  b3 (4)

This operator is also a representation of backlash, well-known negative effect, Fig. 13. Play operator which occurs in mechanical systems (screws, gears). GPIM is preferred in Gr modeling of characteristics which shapes are asymmetric with saturation such as in shape memory alloys, both thermally and magnetically activated and in some cases also in piezo materials. Output of generalized hysteresis model is expressed as single integral of threshold function multiplied by play operator output. For modeling by discrete system, integral is replaced by finite sum of weighted operators, where n is number of used operators:

n y t  p(r )G v(t) (5) pGPI  j rj j0

To improve the accuracy of modeling it is necessary to add for each play operator its weight and for this purpose density function p(r) is implemented

 rj p(rj )   e , rj    j (6) where parameters α, ρ and τ are always positive and are estimated based on measured data. Hysteresis can be successfully reduced by application of its inverse model as cascade compensator. In presented here model, hyperbolic tangent functions (3) and (4) are used. Their analytical inversion can be expressed as arcs hyperbolic tangent function

1  v(t)  a  1 1  3   l (t)  tanh    a2 (7) a1  a0 

The inversed hysteresis model is described by equation

n  1  dv   pˆ(r )Gˆ y (t) for  0 l  j rj r  1   j0  dt yGPI t   (8)  n   1 dv   pˆ(r )Gˆ y (t) for  0  r  j rj r    j0  dt

Parameters (thresholds and density function), used in this equation are re-defined as follows:

j 1 1 rˆ  p (r  r ) , ˆ , pˆ   i  0 (9) j  i j i prj  j j1  i  1; j 0 i0 p0  p(rj )   p(rj ) i0 i0

The presented above theoretical description of hysteresis model and its inversion is used for MSMA hysteresis modeling and compensation. Output of inverse model is presented in Fig. 14. To prove the idea of hysteresis compensation by cascade application of its inverse model, the open loop test is performed. Current described as damped sine signal is changed to position reference, and this signal is given to input of inverse model. Output of this model is the coil current which feeds coils in examined actuator. Result for this compensation is visible in Fig. 15, where the MSMA actuator’s characteristic is almost hysteresis free.

3 1000

2 500 1

Compensationcurrent (A) 0 Measuredposition (µm) 0 0 200 400 600 800 1000 1200 0 200 400 600 800 1000 Position reference (µm) Position reference (µm) Fig. 14. MSMA inverse hysteresis simulation Fig. 15. Compensated hysteresis of MSMA actuator

Summary In the paper the chosen smart materials are briefly presented. Their principle of operation are shortly described. The made at Poznan University of Technology investigations results of these materials are included. Presented in this paper results confirmed that application of feedback system with PID regulator can assure hysteresis compensation of investigated smart materials in real time and the control system can reduce hysteresis and tracking error. Application of generalized Prandtl-Ishlinskii model gives satisfying results of simulation with acceptable level of modeling error. Research proved that cascade hysteresis compensation based on inverse model can significantly reduce hysteresis. Such linearization has a positive effect on performance of closed loop control system. Nowadays the intelligent control and new, smart materials development enabled their application in mechatronic devices. In these devices, a deeper integration of advanced, smart materials with intelligent controllers enable the improved functioning of complex mechatronic systems. Thanks to this, it is possible that in near future the new mechatronic devices will be designed. The mechatronics goal for now and for the future is to develop autonomous, self-learning devices. The term mechatronics is 16

already almost 50 years old. However, the proposed since these years definitions treat mechatronics too wide, which means that every device having mechanical part with embedded electronic controller, is regarded as a mechatronic one. Therefore, the new definition should proposed, which should emphasize the application of smart materials in mechatronics. Nowadays the term mechatronics is extremely broad. It is used to describe every the use of electronic elements in the automation of devices and processes, industrial machines, medical systems, home equipment, energy and power systems, vehicles, military equipment, data communication systems, medicine equipment and many, many others.

Acknowledgments: The research work reported here was supported by the Polish Ministry of Science and Education grants no. 02/22/DSPB/1389.

References [1] Japan Trade Registration No. 946594, 1972. [2] McConaill, P., Drews, P., & Robrock, K. -H. (Eds.)., Mechatronics and robotics. Amsterdam: ICS Press, 1991. [3] Heimann, B., Gerth, W., Popp, K. Mechatronik (Mechatronics), Leipzig: Fachbuchverlag Leipzig, 2001. [4] Bishop C., The mechatronics handbook. Boca Raton, FL: CRC Press, 2002. [5] Bradley D., Dawson D., Burd D., Loader A., Mechatronics electronics in products and processes. London: Chapman & Hall, 1991. [6] Bolton W., Mechatronics: Electronic control systems in mechanical and electrical engineering, Kindle Edition, Pearson Education, 6 issues - the last in 2016, 664 pages. [7] Mechatronics, The Science of Intelligent Machines, A journal of IFAC. https://www.journals.elsevier.com/mechatronics [8] IEEE/ASME Transactions on Mechatronics, http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=3516 . [9] www.mechatronics.colostate.edu/definitions.html (accessed 10.06.2017). [10] International Journal on Smart Material and Mechatronics (IJSMM) http://siaka.unhas.ac.id/ijsmm/news.php?view=36 [11] 3rd Edition International Smart Materials and Surfaces - SMS – Conference. http://www.setcor.org/conferences/SMS-EUROPE-2017 [12] Minase J., Lu T-F., Cazzolato B. and Grainger S., A review, supported by experimental results, of voltage, charge and capacitor insertion method for driving piezoelectric actuators, 2010, Precis. Eng. 34, 692–700. [13] Sędziak D., Basic investigations of electrohydraulic servovalve with piezo-bender element Arch. Technol. Masz. Autom, 2006, 26, 185–190; [14] Sędziak D. and Regulski R., Design and Investigations into the Piezobender Controlled Servovalve, 2015, Solid State Phenomena vol 220, (Trans Tech Publ), pp 520–525. [15] http://www.piceramic.de/products.html [16] Mohd Jani J., Leary M., Subic A., Gibson M.A., A review of shape memory alloy research, applications and opportunities, 2014, Mater. Des. No. 56, pp. 1078–1113; [17] Jokinen T., Ullakko K., Suorsa I., Magnetic Shape Memory materials-new possibilities to create force and movement by magnetic fields, Proceedings of the Fifth International Conference on Electrical Machines and Systems, 2001, vol. 1, pp 20–23. [18] Xu Q., Li Y., Dahl model-based hysteresis compensation and precise positioning control of an XY parallel micromanipulator with piezoelectric actuation, Journal of Dynamic Systems, Mesuremet, and control 132(4), 2010. [19] Gu G., Yang M., Zhu L., Real-time inverse hysteresis compensation of piezoelectric actuators with a modified Prandtl-Ishlinskii model, Review of Scientific Instruments 86(6), 2012.

[20] Mayergoyz I.D., Mathematical Model of Hysteresis, Springer-Verlag, New York, 1991. [21] Brokate M., Sprekels J., Hysteresis and Phase Transitions. New York: Springer, 1996. [22] Stefański F., Minorowicz B., Nowak A., Hysteresis Modelling of a Piezoelectric Tube Actuator Prog. in Autom, Robo. and Meas. Techn. (Springer), 2015, 283–91. [23] Minorowicz B., Nowak A., Stefanski F., “Hysteresis Modelling in Electromechanical Transducer with Magnetic Shape Memory Alloy,” Przegląd Elektrotechniczny, vol. 11, 2014, pp. 244–247. [24] Al Janaideh M., Rakheja S., Su C.-Y., A generalized Prandtl–Ishlinskii model for characterizing the hysteresis and saturation nonlinearities of smart actuators, Smart Materials and Structures, vol. 18, no. 4, 2009. [25] Al Janaideh M., Rakheja S., Su C.-Y., An analytical generalized Prandtl–Ishlinskii model inversion for hysteresis compensation in micropositioning control, Mechatronics, IEEE ASME Transactions on, vol. 16, no. 4, pp. 734–744, 2011.

THROW DOWN A CHALLENGE TO THE PIEZO-MECHATRONIC SYSTEMS DESIGN

Borodinas Sergejus 1, 2, 3, 1Vilnius Gediminas Technical University, Basanaviciaus str. 28a, Vilnius, Lithuania 2Institute of Mechanical Science, Basanaviciaus str. 28a, Vilnius, Lithuania 3Institute for Scientific Research, Studentu str. 39, Vilnius, Lithuania E-mail: [email protected]

Keywords: piezoelectric materials, piezoelectric actuator, mechatronic system.

Abstract

Piezo-mechatronic systems have additional futures comparing with “classic” mechatronic systems. The author briefly described advantages and disadvantages of such systems and present some design principles based on team and own experience in ultrasonic technology field. Moreover, piezoelectric actuator’s application field depends on piezoelectric system design, as shown.

Introduction Actuators are mechanical or electro-mechanical devices that provide controlled movements or positioning which are operated electrically, manually, or by various fluids such as air, hydraulic, etc. This is some kind of devices that convert input energy into mechanical energy, and various actuators have been developed and put to practical use according to various types of input energy. These piezo-mechatronic systems use a piezoelectric actuator which achieves displacement by directly applying deformation of a solid, and thus features a higher displacement accuracy, larger generation force and higher response speed than other types of actuators. These advantages have resulted in the piezoelectric actuator being applied mainly in industrial equipment requiring precision position control. In the sections below, we will talk about piezoelectric actuators application in mechatronic systems, changes in the ﬁelds of application depend on piezo system design. Described some features of the piezoelectric actuator and the future perspectives as well. Author described few ultrasonic motors design created by us during last 15 years using different piezoelectric coefficient, resonant and inertia type piezoelectric mechatronic systems and driving methods as well.

Features of the Piezoelectric Actuators The piezoelectric actuator is a device that makes use of the inverse piezoelectric effect. One of the features is very easy to control small (sub-micron) displacements with applied voltage. Although the expansion of a piezoelectric actuator is very small, it can be controlled to an extremely fine degree, with resolution limited only by the inherent noise and stability of the driver providing the voltage. The motion produced is smooth and continuous because the expansion is a process at the atomic level, and therefore there is no friction or stiction, so that piezoelectric actuators exhibit no wear and tear. Both fast response and high stiffness are one of main characteristics features of piezoelectric actuators. A rapid drive voltage change results in a rapid position change. This property is especially welcome in dynamic applications such as scanning microscopy, image stabilization, switching of valves/shutters, shock-wave generation, vibration cancellation systems, etc. A piezo actuator can reach its nominal displacement in approximately 1/3 of the period of the resonant frequency. Therefore,

piezoelectric actuators respond to an applied voltage with microsecond to millisecond time constants and can therefore produce oscillating motion at high input frequencies. No necessity of a driving coil, ease of implementation of small devices, high energy conversion efﬁciency and low power consumption. Moreover, the force generated by an expanding piezoelectric actuator can be very large-up to several hundreds of newtons. A piezo actuator can operate billions of times without wear or deterioration. Its response speed is exceptional and it is limited only by the inertia of the object being moved and the output capability of the electronic driver.

Applications of the Piezoelectric Actuator The ﬁeld of applications of piezoelectric actuators is comparable to that of electromagnetic or hydraulic actuators. Two basic motions are linear and rotary. The piezoelectric actuator has disadvantages compared to the electromagnetic or hydraulic actuator in terms of its displacement amount. However, the piezoelectric actuator has advantageous from other aspects, including displacement accuracy, generated force and response speed and energy efﬁciency as well as from the aspect of ease of proportional control (multilayer stack) and absence of electromagnetic noise, require no lubrication to operate, they are used in cryogenic and vacuum environments. In applying this technology, engineers must design motion-feedback mechanisms so that voltage can be regulated to create the exact movement required under loaded condition. Based on relatively simple design, minimal moving parts, no requirement for lubrication to operate and the high reliability characteristics, the piezoelectric actuator is used in a variety of industrial, automotive, medical, aviation, and aerospace and consumer electronics applications.

Rotary Piezoelectric Motor in Piezo-mechatronic System  Rotary Embedded System with Speed Control

The rotary type piezoelectric motor using for next example of piezo-mechatronic embedded system is a ring type travelling wave ultrasonic motor (TWUSM) shown on Fig. 1. Design specifications of the used TWUSM are presented in Table 1. Current motor has additional friction layer on stator (Teflon with glass fiber) for increase a life time and operating condition of device.

Table 1. Design specification of used TWUSM

Rated output power 2,5-3 [W] Rated speed 90 [RPM] Rated Torque 2,1-2,6 [kgf∙cm] Driving voltage 95 [V RMS] Two-phase AC (dif.) 90 [deg] Driving frequency 45 [kHz] Size 44 x 44 x 18 [mm] Temperature range -15~70 [0C] Fig. 1. Travelling-wave Weight 80 [g] USM

The mechanical resonant frequency of current ultrasonic motor is from 44.5 to 45 kHz and decrease more than 1 kHz with temperature rise up to 60-70 0C. Revolution speed is very sensitive to the external load as shown on Fig. 2. Besides, dynamic friction and another factors generated speed ripple up to 10-12 RPM. It is highly recommended use motion-feedback control of revolution speed by mean reducing speed dependences on temperature and load.

Special design and control algorithm of piezoelectric motor are proposed. Since the ultrasonic motor rotates around the mechanical resonant frequency, the rotor speed is controlled by driving frequency. The instantaneous motor speed is measured using a rotary encoder. The input data is analyzed

Fig. 2. Open-loop mode with step- Fig. 3. Close-loop mode with wise load torque step-wise load torque by single crystal microcomputer and then driving frequency to the switching two-phase resonant converter through the MOSFET drivers. The switching device in two-phase resonant converter is a monolithic low voltage MOSFET array. For prevention of origin of an open current during the switching process phase-shifter has a dead time zone. The revolving speed characteristics controllable by speed tracking control algorithm, is shown on Fig. 3. It is noted that the speed ripple is about 3 %. Moreover, the reaction of control system to the step- wise load is very insignificant, because, the sampling period is very small. The temperature rise variations compensated by micro controller too. Design specifications of the proposed embedded system for TWUSM are listed in Table. 2. Electronic driver part, control system, sensors and TWUSM are integrated to the one embedded system as shown on Fig. 4.

Table 2. Design specification of embedded system

Dc power supply 15 [V ] Max DC input power 7 [W] Speed control range 10-90 [RPM] (manual or by RS-232) Speed ripple of USM 2~3 [%] Speed control resolution 8 [bits] Speed control error  1 [LSB] Rated Torque (max value) 2,1-2,6 [kgf∙cm] Driving AC voltage 95 [V RMS] Two-phase AC (dif.) 90 [deg] Driving frequency range 44,7~47 [kHz] with 1 kHz drift compensation Size with USM 44 x 44 x 35 [mm] Temperature range -15~70 [0C] Weight ~ 110 [g] Fig. 4. Piezo-mechatronic embedded system

 Mechanical Piezoelectric Gyroscope Among mechanical gyroscopes it is stand out rotary gyroscope - quickly rotating firm body (rotor), which rotation axis is capable to change orientation in space. Thus gyroscope rotation speed considerably exceeds speed turn axis of its rotation. At influence of the moment outside force of round axis, a perpendicular of rotor rotation axis, the gyroscope starts to turn round an axis precession, which is perpendicular to the moment outside forces. Piezo gyroscopes consume much more a smaller current in comparison with mechanical, maintain the big accelerative forces (are less sensitive to damage), allow more precisely to react to models turns. As for struggle against drift, that in cheap models piezo gyroscopes there is simply control "zero", and

in more expensive - automatic installation of "zero" by the microprocessor at giving power supply and compensation drift temperature sensors. Structure of the symmetrical coplanar trimorph piezoelectric actuator is shown on Fig. 5. Symmetrical coplanar trimorph piezoelectric actuator included two piezoelectric elements with four electrodes El1 - El4 and the metal plate MP [2]. Assembled motor with two symmetrical mass is shown on Fig. 6. Rotating speed of designed piezoelectric motor is up to 4000 RPM.

Fig. 5. Symmetrical Fig. 6. Symmetrical coplanar coplanar trimorph actuator Fig. 7. Mechanical piezoelectric based ultrasonic motor gyro embedded system trimorph piezoelectric

Mechanical piezoelectric gyroscope included frame, sensors and microcontroller is shown on Fig. 7. Application field of proposed mechanical gyro system included mechanical object position stabilization in space (anti-shake etc.).

Linear Piezoelectric Actuator in Piezo-mechatronic System  Linear Embedded System with Speed Control Principle of “shaking beam” actuator is based on the exciting the ends of the “shaking beam” indicated by ab in Fig.8 by two sources of the harmonic vibrations that have identical frequency, but phases are different by 2 (see Fig. 8) [3]. The ultrasonic linear piezoelectric actuator as shown on Fig. 9 using two half wave converters with four d33 piezo ceramics in each part. Finally, the properties of the linear ultrasonic motor are dependent on the contacting materials between the moving parts.

Fig. 8 Mechanical system of Fig. 10 Piezo-mechatronic system “shaking beam” Fig. 9 Piezoelectric actuator

Nano-positioning system using the linear ultrasonic actuator was consisted of the base part, moving part, ultrasonic linear motor, and embedded linear encoder to ensure nano metric precision as

shown in Fig. 10. The nano-positioning system was designed to move one direction with respect to the ﬁxed frame and the embedded linear encoder measured this movement and transferred data to control system. The system consists of the linear ultrasonic motor ﬁxed on the stage with preload, linear guide, optical linear encoder (Canon: ML-16/80 with effective length 80 mm, linearity of 0.2 µm, 20 nm of output resolution, and 150 mm/s maximum response speed). The phase shifted sinusoidal-wave voltages are generated by high voltage driver. Micro controller provides the speed and mechanical motion control of the stage by output data from optical linear encoder. The system has maximum feeding velocity 300 mm/s at open-loop and reduced in close-loop mode (optical encoder limitation).

 Inertia Type Piezoelectric Motor Application in Piezo-mechatronic system The linear motion of an inertia linear motor is operated by a principle of inertia displacement. The motor consists of three parts, which are a transducing part, shaft and mobile element (Fig. 11). The transducing part is composed by a piezoelectric ceramic disk and a metal disk, which is attached on the piezoelectric ceramic disk. The transducing part is driven by the saw tooth electrical potential applied to the electrode on the piezoelectric ceramic disk. The piezoelectric ceramic disk generates the one of the radial modes, which is periodical extension and contraction on the radius direction of the piezoelectric ceramic disk [4]. The tiny ultrasonic linear motor can be realized by the central movement, which is the maximum displacement of the up-and- down movement. The movement should transfer to the shaft of the motor, without any distortions. The mass of the shaft must be lighter than mass of the transducing part. If the shaft mass is heavier than transducing part, the mobile element can be created a non-uniformity movement by distortion of the shaft. The shaft is made as the hollow thin-wall cylinder for this purpose. Precision micro movement with low power consumption, Fig. 11. The structure of tiny ultrasonic good controllability and simple electronic driver design is one of linear motor; prototype (left) and advantages of inertia type piezoelectric actuator. Therefore they design for mass production (right). find wide application in different field from digital camera and scanner to medicine equipment. The Korean company piezo-tech has a more than 15 years’ experience in manufacturing of proposed ultrasonic motor and last few years expanded scope of application [5]. Nowadays, company export many motors to another companies and devices surround the world. One of the current products is Optical Image Stabilizer (Fig. 12) and Autofocusing mechanism module (Fig. 13). Optical Image Stabilizer has a two piezoelectric ultrasonic motor (see Fig. 11 - from right). React to the external sensors

Fig. 12. Optical Image Fig. 13. AF module Stabilizer 23

output data the microprocessor send information to the electronic driver of motors and move the image sensors to stabilize the image. This principle also incorporates Samsung's OPS (Optical Picture Stabilization) technology and the ASR (Advanced Shake Reduction) system for double anti-shake protection as shown in Fig. 14. Camera shake is caused by many factors, such as normal shaking of the hand, zooming, or insufficient light. The NV7 has built-in OPS (Optical Picture Stabilization), an optical anti-shake technology, to minimize camera shake and to deliver clearer resolution. This system uses an Image Sensor Shift mechanism included two piezoelectric linear ultrasonic motors (Fig. 11- from right) that moves the sensors in the opposite direction to the movement of the lens (caused by camera shake) and corrects the shake. A product of Samsung's superior technology, OPS Fig. 14. Digital camera with OPS mechanizm translates any movement detected by its two shake- detection sensors into an algorithm, and corrects even the tiniest of shakes through this process.

Summary As described above, the piezoelectric actuator is extending its ﬁeld of application from industrial machinery to compact electronic equipment. The piezo-mechatronic systems, in fact, change a design philosophy and take a chance to new way of micro/nano technology. Very important role play integration between science, technology and business. Comparing with “classic” mechatronic systems piezo- mechatronic systems has a few advantages, which open absolutely different application field. All projects in this paper based on principles: idea, R&D, experiment and manufacturing. Some of ideas after few years of investigation go directly to the mass production stage.

REFERENCES [1] P. Vasiljev, S. Borodinas, R. Bareikis and L. Vasiljeva, Technical Report. Development of Piezoelectric Motor Gyroscope for USN Applications, Vilnius, Lithuania, 2010. [2] S. Borodinas, P. Vasiljev, D. Mazeika, The optimization of a symmetrical coplanar trimorph piezoelectric actuator. Sensors and Actuators, A 200, p. 133-137, 2013. [3] S.N. Borodin, P.E. Vasiljev, K. Hyun-Jai, Y. Seok-Jin, New Principles of Designing of Linear Ultrasonic Motor. Proceeding of the International Sensor Conference, Seoul, Korea, 2001. [4] K. Hyun-Phill, K. Sangsig, S. Borodinas, P. Vasiljev, K. Chong-Yun, Y. Seok-Jin, A novel tiny ultrasonic linear motor using the radial mode of a bimorph. Sensors and Actuators, A 125, p. 477– 481, 2006. [5] http://www.piezo-tech.com/eng/index.php?hCode=INTRO_01_01

DYNAMIC BEHAVIOUR OF GFRP FOOTBRIDGE MODEL

Darius Bacinskas1,a, Arturas Kilikevicius2,b, Arvydas Rimkus1,c *, Deividas Rumsys1,d Adas Meskenas1,e 1 Department of Bridges and Special Structures, Vilnius Gediminas Technical University, Vilnius, Lithuania 2 Institute of Mechanical Science, Vilnius Gediminas Technical University, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: GFRP composite; footbridge model; dynamic testing, free vibration, frequency.

ABSTRACT

This paper presents experimental and numerical investigations of dynamic behaviour of a simply supported glass fibre reinforced polymer (GFRP) bridge model. Space truss bridge prototype was assembled using GFRP profiles produced by Fiberline Composites Ltd, steel bolts and GFRP brackets. To establish free vibration parameters of the composite bridge, the structure was excited by impact induced flexural, transversal and torsional vibrations. The results of dynamic tests and respective numerical modelling were compared in order to access the ability to predict the structural response of the GFRP footbridge using the finite element (FE) model. Latter model of the pedestrian bridge prototype was created employing FE software SolidWorks. The main results related with free vibration mode shapes and corresponding frequencies are presented and discussed. Comparative analysis has demonstrated good agreement between experimental and numerical results (the margin of error varied from 0,3 up to 10,5%) and indicated that designed and tested bridge model has a sufficient reserve of structural stiffness. The results showed that GFRP profiles are suitable for real pedestrian bridge superstructures.

REFERENCES

[1] Bačinskas, D., Rimkus, A., Rumšys, D., Meškėnas, A., Bielinis, S., Sokolov, A., Merkevičius, T. (2017). Structural Analysis of GFRP Truss Bridge Model. Procedia Engineering, 172, 68-74. [2] Bakis, C. E., Bank, L. C., Brown, V., Cosenza, E., Davalos, J. F., Lesko, J.J., Machida, A., Rizkalla, S.H., Triantafillou, T.C. (2002). Fiber-reinforced polymer composites for construction – state-of-the-art review. Journal of composites for construction, 6(2), 73-87. [3] Burgoyne, C. J., Head, P. R. (1993). Aberfeldy Bridge – an advanced textile reinforced footbridge. In TechTextil Symposium, 7-9. [4] Casas, J. R. (2015). The Bridges of the Future or the Future of Bridges? Frontiers in Built Environment, 1, 3. [5] Heinemeyer, C., Butz, C., Keil, A., Schlaich, M., Goldack, A., Trometer, S., Lukic, M., Chabrolin, B., Lemaire, A., Martin, P. O., Cunha, A., Caetano, E. (2009). Design of Leightweight footbridges for human induced vibrations. JRC Scientific and Technical Reports, 1-82. [6] Kumada, T., Yamada, S., Johansen, E., Wilson, R. (2009). Static and Dynamic Behavior of a Pultruded FRP Truss Footbridge. The Second Official International Conference of International Institute for FRP in Construction for Asia-Pacific Region, 9-11 December 2009, Seoul, Korea. 355–361. [7] Reis, A., Pedro, O., José, J. (2011). Composite truss bridges: new trends, design and research. Steel Construction, 4(3), 176-182. [8] Sánchez-Silva, M., Frangopol, D. M., Padgett, J., & Soliman, M. (2016). Maintenance and Operation of Infrastructure Systems: Review. Journal of Structural Engineering, 142(9), 1-17. [9] Stratford, T. (2012). The condition of the Aberfeldy Footbridge after 20 years in service. In Structural Faults and Repair 2012, 3-5.

REDUCTION VIBRATION OF SYNTHESIZED DRIVING SYSTEMS TO THE REQUIRED VALUES OF AMPLITUDES

Dzitkowski Tomasz1, a*, Dymarek Andrzej1,b, Brodny Jarosław2,c 1 Silesian University of Technology, Faculty of Mechanical Engineering, Institute of Engineering Processes Automation and Integrated Manufacturing Systems, Konarskiego 18A, Gliwice, Poland 2 Silesian University of Technology, Faculty of Organization and Management, Institute of Production Engineering, Roosevelta 26, Zabrze, Poland E-mail: a [email protected], [email protected], [email protected]

Keywords: dynamic flexibility, mobility, accelerance, natural circular frequencies, damped circular frequencies

ABSTRACT

Technological development, characterized by an increase in power and rotational speed of machines and devices drives, is inextricably linked with the growth in their dynamic activity. This may have a negative effect on stability, efficiency and reliability of machines and devices themselves, but may also adversely affect other mechanisms and living organisms in their close environment. Hence it is needed the continuous development of research on reducing vibro-activity in the existing and designed machines and equipment. While there are many vibration reduction methods and techniques in already existing machines and equipment, the use of conventional design methods could not guarantee creation of designs with pre-established dynamic properties. At the same time, laborious and time-consuming classical methods evoked interest in network methods facilitating automatized calculations, including methods of analysis and synthesis of vibrating systems [1-8]. The paper presents the task of synthesizing machine drive systems. The passive synthesis of drive systems is presented. This task consists in determining the parameters and structure of a system for an assumed sequence of resonance and anti-resonance frequency values. The set of machine drive system models created in this way, particularly the parameters of these systems meeting the desired dynamic properties, constitutes the basis for the qualitative model search. The main feature of the mechanical systems obtained in such way is the fact that the determined system parameters do not change over time as well as the fact that it is not necessary to provide an external source of energy to meet the assumed properties. The selection of a model from a synthesized group depends on the machine operating conditions. Machine can work close to the resonance state only when the damping value of the system is high enough because of the highest stress level. There are many methods making it possible to reduce the unwanted system vibrations. These methods include: passive vibration reduction, active vibration reduction, semi-active vibration reduction and mixed (hybrid) methods. The research on the passive and active synthesis of mechanical systems is developed by the authors of this paper. The next step presents an active synthesis of the obtained machine drive system models. This task makes it possible to modify the pre-assumed dynamical characteristics in the form of the resonance and anti-resonance frequency sequence, by reducing resonance frequencies to the required values of the amplitude of vibration of the system. The tool that makes possible to modify the characteristics is the determined controlling force to generate which it is required to provide an additional source of energy to the system. The vibration reduction method, presented in this paper, can be classified as one of the design methods used in designing vibrating discrete systems, as sub-components of machines, with desired dynamic properties [1 - 8]. This work is a continuation of research on development of methods of synthesis of passive and active reduction of vibration in mechanical systems. Earlier work on active synthesis of mechanical systems focused on nominating a single control force reducing the vibration

amplitude of selected resonance frequencies [2, 3, 5, 6]. In the case of passive synthesis, certain parameters of damping vibration components (dampers) were determined for one of the preselected vibration amplitude values [1, 4, 7, 8]. This study presents the use of active synthetic methods to determine parameters of setting forces, reducing vibrations of selected resonance frequencies. At the same time, it enables implementation of values of the forces in the system by means of passive damping components, as well as by combination of active and passive components in the system. Such extension of the synthesis task gives the designer a great number of possibilities for selecting optimal parameters of the designed system.

REFERENCES

[1] T. Dzitkowski, A. Dymarek A, Method of active and passive vibration reduction of synthesized bifurcated drive systems of machines to the required values of amplitudes. Journal of Vibroengineering. 17/4 (2015) 1578-1592. [2] A. Dymarek, T. Dzitkowski, Inverse task of vibration active reduction of Mechanical Systems. Mathematical Problems in Engineering. (2016). [3] T. Dzitkowski, A. Dymarek, Active synthesis of machine drive systems. Applied Mechanics and Materials. 430 (2013) 178-183. [4] A. Dymarek, T. Dzitkowski, Passive reduction of system vibrations to the desired amplitude value. Journal of Vibroengineering. 15/3 (2013) 1254-1264. [5] T. Dzitkowski, A. Dymarek, Active reduction of identified machine drive system vibrations in the form of multi-stage gear units. Mechanika, 20/ 2 (2014) 183-189. [6] T. Dzitkowski, A. Dymarek, Active synthesis of machine drive systems using a comparative method. Journal of Vibroengineering. 14/2 (2012) 528-533. [7] T. Dzitkowski, A. Dymarek, Passive reduction in the identified vibrations of the machine drive system in the form of multistage gear units. Solid State Phenomena. 220-221 (2015) 182-187. [8] A. Dymarek, T. Dzitkowski, The method for determining the vibration-damping elements for the mechanical system to obtain the desired amplitude value. Applied Mechanics and Materials. 657 (2014) 644-648.

PRINCIPLES OF DESIGN AND FORMATION OF A SELF-SUPPORTING SKELETON IN CONSTRUCTING BUILDINGS OF COMPLEX GEOMETRIC SHAPES WITH THE USE OF SHOTCRETE TECHNOLOGY

Sergey Bugayevskiy1, a, Vladimir Babaev2, b, Valery Shmukler3, c, Vladymir Gerasymenko4, d, Andreі Zadorozhny5, e, Gintas Viselga6, f* 1 Kharkiv National Automobile and Highway University, Department of Bridges, constructions and structural mechanics, Ukraine 2 O.M. Beketov National University of Urban Economy in Kharkiv, Rector, Ukraine 3 O.M. Beketov National University of Urban Economy in Kharkiv, Head of the Department building construction, Ukraine 4 Kharkiv National University of Construction and Architecture, Head of the Department of Graphs, Ukraine 5 Kharkiv National University of Construction and Architecture, Department of Mechanization of construction processes, Ukraine 6Vilnius Gediminas Technical University, Department of Mechanical and Materials Engineering, Lithuania E-mail: a [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: self-supporting skeleton (frame), reinforcing cage, non-removable inserts cavity-makers, shotcrete technology.

ABSTRACT

In recent years, there has been a tendency around the world to erect buildings of complex geometric shapes with the help of the latest 3D-modeling-and 3D-printing technologies to create unique architectural forms. At the same time the designers and civil engineers have got various technical problems associated with the production and decreasing the cost of formwork with complex geometry, with creation of reinforcement cages, including self-supporting ones, the process of concreting, etc. This paper shall consider the basic modern technologies used for the construction of buildings or their parts with a complex geometric shape. The article describes new architectural and construction system “Monofant” developed for constructing monolithic reinforced-concrete buildings and structures with complex geometric elements. The article stresses that non-removable inserts cavity-makers are used in them to reduce the weight of all the basic designs in a frame building. The article also shows the results of the design and formation of a self-supporting skeleton in constructing buildings of complex geometric shapes without the use of formwork. The design of the offered self-supporting core consisting of a spatial curved reinforced cage and non-removable inserts cavity-makers, allows building lightweight design with the use of sprayed concrete technology for formless concreting. The use of internal permanent formwork construction allows weight reduction while working with a complex geometric surface and increases the bearing capacity of the building or structure erected. The construction of complex architectural forms depends on the efficient use of shotcrete technology, as well as the application process in the formation of concrete mix design i.e. proper selection of technology and equipment for shotcreting.

INVESTIGATION OF OIL WHIP AND WHIRL INFLUENCE ROTOR SYSTEM WITH HYDRODYNAMIC ADAPTIVE SEGMENTAL BEARING OF WORKING STABILITY

Audrius Čereška Vilnius Gediminas Technical University, Department of mechanical Engineering, Basanavičiaus str. 28, LT- 03224, Vilnius, Lithuania E-mail: [email protected]

Keywords: Adaptive bearing, hydrodynamic, rotor system, segment, orbit.

ABSTRACT

This paper presents tests of the effects oil creates to working performance of bearing rotor system. The object of investigation is rotor system, rotor-oil-hydrodynamic adaptive segmental bearings with segments connecting elastic elements. Elastic elements inhibit the oil flow turbulence and so reduce rotor vibration alarm. With such structure of bearing can achieve stable rotation of the rotor work in a wider range of frequencies. These bearings have two oil streams: the carrying and circulation. It is presents separate models of bearing segments being different load cases. It is used stand with special diagnostic equipment for experimental research. Investigations were carried out rotor systems working range from 0 to 6000 rev/min. After investigations is determined influence in the bearing of lubricant whirls for the stability and reliability of rotor system work.

REFERENCES

[1] H. Allmaier, C. Priestner, C. Six, H.H. Priebsch, C. Forstner, F. Novotny-Farkas, Predicting friction reliably and accurately in journal bearings-a systematic validation of simulation results with experimental measurements, Tribology International, 44 (2011) 1151-1160. [2] V. Barzdaitis, G. Cinikas, Condition monitoring data formats used in rotating machinery diagnostics, Mechanika, 2 (1997) 40-48. [3] V. Barzdaitis, S. Gečys, D. Šeštakauskas, A. Gargasas, Investigation of vibration of turbogenerator, Mechanika, 7 (2002) 50-54. [4] T. Dimond, A. Younan, P. Allaire, A review of tilting pad bearing theory, International Journal of Rotating Machinery, 2011 (2011) 23. [5] J.P. Arenas, Enhancing the Vibration Signal from Rolling Contact Bearing Using an Adaptive Closed-Loop Feedback Control for Wavelet De-Noising, Strojniški vestnik - Journal of Mechanical Engineering, 51 (2005) 184-192. [6] D.E.Bently, Rotating Machinery Measurements 101 Orbit, 15 (1994) 4-6. [7] J. Ondrouch, P. Ferfecki, Z. Poruba, Active vibration reduction of rigid rotor by kinematic excitation of bushes of journal bearings, Tehnički vjesnik – Technical Gazette 49 (2010) 107-110. [8] H.P. Tejas, A.K. Darpe, Vibration response of a cracked rotor in presence of rotor–stator rub, Journal of Sound and Vibration 317, 3-5 (2008) 841-865. [9] V. Barzdaitis, M. Bogdevicius, The Dynamic Behavior of a Turbine Rotating System, Strojnški vestnik - Journal of Mechanical Engineering 52 (2006) 653-661. [10] A. Chasalevris, D. Sfyris, Evaluation of the finite journal bearing characteristics, using the exact analytical solution of the Reynolds equation, Tribology International 57 (2013) 216-234. [11] H. Liu, H. Xu, P.J. Ellison, Z. Jin, Application of computational fluid dynamics and fluid-structure interaction method to the lubrication study of a rotor-bearing system, Tribology Letters 38 (2010) 325-336. [12] G.G. Vignolo, D.O. Barila, L.M. Quinzani, Approximate analytical solution to Reynolds equation for finite length journal bearings, Tribology International 44 (2011) 1089-1099. [13] A. Muszynska, D.E. Bently, Fluid-induced instabilities of rotors: Whirl and whip – summary of results, Orbit 17 (1996) 7-15.

[14] A. Muszynska, Alford and the destabilizing forces that lead to fluid whirl/whip, Orbit 19 (1998) 29-31. [15] A. Muszynska, C.T. Hatch, Oil whip of a rotor supported in a poorly lubricated bearing, Orbit 19 (1998) 4- 8. [16] A. Muszynska, Vibrational diagnostics of rotating machinery malfunctions, International Journal of Rotating Machinery 1 (1995) 237-266. [17] A.H. Marcinkevičius, Automatic regulation of clearance in a tilting pad journal bearing, Mechanika 18 (2012) 5-9. [18] A.H. Marcinkevičius, M. Jurevičius, Automatic Control of Loading Forces in a Tilting Pad Journal Bearing, Hindawi Publishing Corporation Advances in Mechanical Engineering 2014 (2014) 9. [19] V. Meruane, R. Pascual, Identification of nonlinear dynamic coefficients in plain journal bearings, Tribology International 41 (2008) 743–754. [20] L.E. Rodriguez, D.W. Childs, Frequency dependency of measured and predicted rotordynamic coefficients for aload-on-pad flexible-pivot tilting-pad bearing, Journal of Tribology 128 (2006) 388-395. [21] D. Carbonara, Jr. Duarte, M.L. Bittencourt, Comparison of journal orbits under hydrodynamic lubrication regime for traditional and Newton-Euler loads in combustion engines, Latin American Journal of Solids and Structures 6 (2009) 13-33. [22] S. Strzelecki, L. Kuśmierz,G. Ponieważ, Thermal deformation of pads in tilting 5-pad journal bearing, Eksploatacja i Niezawodnosc – Maintenance and Reliability 38 (2008) 12–16. [23] D.J. Hargreaves, M. Fillon, Analysis of a tilting pad journal bearing to avoid pad fluttering, Tribology International 40 (2007) 607-612. [24] K. Kyureghyan, W. Piekarski, Analysis of determining pressure distribution in crank bearing, Eksploatacja i Niezawodnosc – Maintenance and Reliability 40 (2008) 19-24. [25] V. Barzdaitis, G. Cinikas, Condition monitoring data formats used in rotating machinery diagnostics, Mechanika 2 (1997) 40-48. [26] M. Vasylius, R. Didžiokas, P. Mažeika, V. Barzdaitis, The rotating system vibration and diagnostics, Mechanika 72 (2008) 54-58. [27] R.A. Makowski, R. Zimroz, Adaptive Bearings Vibration Modelling for Diagnosis, Adaptive and Intelligent Systems 6943 (2011) 248-259.

CONTROL OF THE 6-AXIS ROBOT USING A BRAIN-COMPUTER INTERFACE BASED ON STEADY STATE VISUALLY EVOKED POTENTIAL (SSVEP)

Arkadiusz Kubacki1, a *, Andrzej Milecki1, b * 1Faculty of Mechanical Engineering and Management, Division of Mechatronics Devices, Poznan University of Technology, Piotrowo 3, 61-138 Poznań E-mail: [email protected], [email protected]

Keywords: SSVEP, Brain-Computer Interface, electroencephalography, robot control.

ABSTRACT The paper describes the research on the possibility of control of 6-axis robot produced by Mitsubishi using a brain-computer interface (BCI) based on Steady State Visually Evoked Potential (SSVEP). Electroencephalography is a non-invasive method used to record the activity of the brain from the examined person skull through the electrodes [1]. Currently, the most promising systems capable of communication with a computer for bedridden patients are brain-computer interfaces. There are ample opportunities to monitor brain activity [2], like: - Electroencefalography (EEG), - Positron emission tomography (PET), - Functional magnetic resonance imaging (fMRI), - Magnetoencephalography (MEG). At the moment, due to the low prices of the EEG, this method is developing rapidly [3]. Steady- State Visually Evoked Potential (SSVEP) is a periodic call of evoked potentials through repeated visual stimulation. Usually, the frequency of flicker is more than 6 Hz [4]. As stimulating element usually a flashing light is used. The first step of the investigations presented in the paper is to project and make a blinking element. Authors have created special lights with dimensions of 45x45x45 mm. Inside it, there is a 3W Power LED (Fig. 1). Thanks to the RGB LED there is possible to flash a light in different colors. A control module based on the Atmega 328P microcontroller has been developed, which allows to set the diode frequency between 5 and 50 Hz and set the brightness of the diode in the range of 0 to 100%.

Fig. 1. Blinking module

After constructing the research stand, authors have done research on the duration of the response on the stimulus. They checked up what time the system is able to generate an output signal which can

be recognized and used to control of the robot and how the blinking frequency influence on this response time. At the next stage, studies were conducted on the recognition of most suitable colors used to stimuli the human operator. Thanks to the RGB LED, following colors were used: red, green, blue, purple, yellow and orange. In the latter part of the investigations, the effect of brightness on time and the number of recognized stimuli were checked up. The last step of the work described in this paper was to create a brain-computer interface to control the robot. To this end at first a desktop with flashing lights for navigation through the menu by the user, was developed. The user was able to select several predefined programs stored in the robot's memory. These programs were designed for the robot to help a paralyzed person, i.e. give a drink, raise or lower the headboard, turn on and off the TV, etc. The second option of the created interface was to allow the user to move individual joints of robot. For this purpose, the user looks at the flashing lights assigned to the respective axis of the robot. The maximum number of correctly detected flashes with different light frequencies was checked. The authors also attempted to fix the flash modules directly on the robot (Fig. 2).

Fig. 2. Mitsubishi robot with marked places for blinking module

REFERENCES

[1] T. Zyss, "Zastosowanie układu 10-20 w rozmieszczaniu elektrod do EEG." Przedsiębiorstwo Informatyki Medycznej ELMIKO, 2007. [2] J. R. Wolpaw, N. Birbaumer, D. J. McFarland, G. Pfurtscheller, and T. M. Vaughan, “Brain–computer interfaces for communication and control,” Clinical Neurophysiology, vol. 113, no. 6, pp. 767-791, 2002. [3] L. Bi, X. a Fan, K. Jie, T. Teng, H. Ding, and Y. Liu, "Using a Head-up Display-Based Steady-State Visually Evoked Potential Brain-Computer Interface to Control a Simulated Vehicle," IEEE Transactions on Intelligent Transportation Systems, vol. 15, no. 3, pp. 959-966, 2014. [4] Z. Lin, C. Zhang, W. Wu, and X. Gao, "Frequency Recognition Based on Canonical Correlation Analysis for SSVEP-Based BCIs," IEEE Transactions on Biomedical Engineering, vol. 53, no. 12, pp. 2610-2614, 2006.

CALCULATION POSSIBILITIES OF 3D SURFACE ROUGHNESS PARAMETERS

Natalija Bulahaa *, Janis Rudzitisb 1Riga Technical university, Viskalu street 36A, Riga, LV-1006, Latvia E-mail: [email protected], [email protected]

Keywords: surface texture, Pearson criterion, 3D roughness parameters, distribution function.

ABSTRACT

Nowadays, a great interest is paid to engineering tasks solution, it is the determination of wear, surface contact area, the coefficient of friction, surface contact deformations. Surface roughness parameters, which define details surface quality and exploitation characteristics, play a huge role in these types of tasks. Surface with irregular roughness very often is modeled by normal random field of two parameters X, Y, for which the typical is: • Symmetrical arrangement of random variable in relation to its average value. It means, that roughness parameter Ssk - skewness of ordinates distribution function, has to be equal to "0". • Kurtosis of roughness ordinates distribution function, which is characterized by roughness parameter Sku, has to be equal to "3". • The probability that surface ordinates values will be grouped in interval from -3σ to + 3σ have to be equal to 99.7% , where σ is a root mean square deviation of distribution function. • Empirical distribution of roughness ordinates has to comply with the theoretical with a high probability, which have to be checked by Pearson criterion [1]. In this work roughness measurement experiments for surfaces with irregular roughness were carried out with the aim to determine the roughness parameters and the ordinates distribution histograms using modern measuring equipment Taylor Hobson Talysurf Intra 50 [2]. Using the obtained experimental data, Prison criterion calculations were made for surfaces, obtained by grinding operations, spark erosion, sandblasting, shot peening and lapping in order to check the compliance of ordinates distribution function to normal Gaussian distribution law. While the calculations it was established that the normal Gaussian distribution law is appropriate for all types of such surfaces, as evidenced by compliance of calculated Pearson coefficient to its tabulated values with a probability greater than 90%. The next step was the calculations of several 3D roughness parameters (from the standard ISO 25178-2 [3]) using the normal random field formulas [4,5] with the aim to determine the relevance between modeled surface parameters and experimental data. The values of parameters Sa, Sp, Spc, Sdq, Sdr were compared with the experimental one. According to the obtained results it was concluded that calculated values of surface roughness parameters are quite close to the values obtained by measuring equipment Taylor Hobson. It can be explained by the surface roughness ordinates distribution, particularly by skewness Ssk and kurtosis Sku, which do not fully comply with normal distribution law [6], that why we can see the differences between the theoretical and real values of surface roughness parameters. In addition these results may be affected by the limited number of experiments. Nevertheless the obtained formulas may be applicable for 3D roughness parameters determination.

REFERENCES

1. V.S.Pugachev, Probability Theory and Mathematical Statistics for Engineers, first ed., Pergamon press, U.K., 1984. 2. Exploring Surface Texture, 7th edition. Great Britain: Taylor Hobson Limited, 2011, 110 p., [online] [01.03.2016], Available at: http://www.taylor-hobson.com/uploads/learningzone/ metrologybooks/Exploring%20Surface%20Texture%202014.pdf 3. LVS EN ISO 25178-2 standard “Geometrical product specifications (GPS) - Surface texture: Areal - Part 2: Terms, definitions and surface texture parameters” 4. K.J.Stout, P.J. Sullivan, W.P. Dong, E. Mainsah, N.T. Mathia., H. Zahouani, Development of Methods for Characterization of Roughness in Three Dimensions, first ed., Penton Press, London, 2000. 5. J. Rudzitis, Contact mechanics of surface, second part, RTU, Riga, 2007. 6. N.Bulaha, J.Rudzitis. Analysis of model and anisotropy of surface with irregular roughness: submitted to proceedings of 16th International Scientific Conference on Engineering for Rural Development (2017).

APPLICATION OF THE FRACTIONAL ORDER CONTROLLER IN ELECTROHYDRAULIC SERVO DRIVE

Dominik Rybarczyk1, a *, Andrzej Milecki1, b * 1Faculty of Mechanical Engineering and Management, Division of Mechatronics Devices, Poznan University of Technology, Piotrowo 3, 61-138 Poznań E-mail: [email protected], [email protected]

Keywords: electrohydraulic serv odrive, fractional order control, proportional valve.

ABSTRACT Presented here paper describes the use of the fractional order controller in the electrohydraulic servo drives. In the literature from the last 10 years, only a few papers focused on the applications of fractional order calculus in electrohydraulic actuators [1, 2, 3]. The first step of the investigations presented in the paper is to build a simulation model of the electrohydraulic drive for testing of the controller parameters. Basic equations describing the proportional valve and hydraulic cylinder are formulated and its simulation model is proposed and implemented in Matlab-Simulink software. Chosen nonlinearities like square root flow characteristics are included in this model. This model is used to test the development of fractional order PID controller and its application in electrohydraulic servo drive.

p 0 K l - Q - p a E 0 1 a F a A F obc V a s - - .. . x F 1 y 1 y 1 y K  p K Qp Va m s s - - - E 0 1 p b - aA D V s F Q b b b

K l +K vb

Fig. 1. Linear model of electrohydraulic servo drive In order to test the proposed control method, the dedicated test stand is built. An electrohydraulic servo drive control system is implemented in PLC, working under real time operating system. The investigations are performed for different coefficients of fractional PID regulator. The step responses obtained in simulations are presented in the paper. These characteristics are compared with results obtained in experimental investigations using the Integral Absolut Error method.

PLC with touch panel Power Panel 500 C

Real time operating system Automation Runtime PC with Matlab Simulink software

DAC

ADC

x Proportional valve amplifier

x Magnetostrictive position sensor built in hydraulic cylinder

T P

Hydraulic supply

Fig. 2. The scheme of control stand

The control program is written in Structured Text and ANSI C languages. For approximation Authors used Oustaloup method detailed described in [4, 5]. The continuous fractional order transfer functions taken from the Oustaloup calculations, after discretization process, are directly implemented on the PLC. a) b)

PLC with touch Proportional Hydraulic cylinder PC for collected data valve panel

Fig. 3. a) View of the electrohydraulic servodrive, b) Fractional PID controller implemented on PLC

REFERENCES

[1] S. Ijaz, M. A. Choudhry, A. Ali, AND U. Javaid, Application of Fractional Order Control Technique to an Electro-Hydraulic Position Servomechanism, Mehran University Research Journal of Engineering & Technology, Volume 34 Issue S1, August, 2015 [ISSN 0254-7821]. [2] T. Sangpet and S. Kuntanapreeda, Force Control of an Electrohydraulic Actuator Using a Fractional-Order Controller, Asian Journal of Control, vol. 15, no. 3, pp. 764–772, May 2013. [3] Jiangbo Zhao, Junzheng Wang, Shoukun Wang, “Fractional order control to the electro-hydraulic system in insulator fatigue test device”, MECHATRONICS 23(7):828-839, 2013. [4] K. Oprzędkiewicz and T. Kołacz, A Non Integer Order Model of Frequency Speed Control in AC Motor, in Challenges in Automation, Robotics and Measurement Techniques, R. Szewczyk, C. Zieliński, and M. Kaliczyńska, Eds. Springer International Publishing, 2016, pp. 287–298. [5] A. Tepljakov, E. Petlenkov, and J. Belikov, “FOMCON: a MATLAB toolbox for fractional-order system identification and control,” International Journal of Microelectronics and Computer Science, vol. 2, no. 2, pp. 51–62, 2011.

STRUCTURE PARAMETERS OF RUBBER MODIFIED IN POLYETHYLENE OXIDE

Elena P. Uss1,a, Andrei V. Kasperovich1,b, Zhanna S. Shashok1,c 1Belarussian State University of Technology, Sverdlova str., 13a, 220006, Minsk, Republic of Belarus E-mail: [email protected], [email protected], [email protected]

Keywords: butadiene-acrylonitrile rubber, elastomer, sealing article, modification, liquid media, polyethylene oxide.

ABSTRACT

The aim of this work was to study structural features of elastomeric compositions modified in nonionic surfactant medium. As objects for our study, we used filled elastomer compositions based on butadiene-acrylonitrile rubber of grade BNRS-18. Rubber compositions based on these rubbers are widely used in the production of oil- and gasoline-resistant sealing items, working in friction of motor units under the influence of aggressive media, high temperatures, limited grease and etc. Elastomeric compositions based on butadiene-acrylonitrile rubber were molded and cured in a hydraulic press to a certain degree of cure, in which the samples have the necessary frame, monolithic and freely removed from the mold without breaking their geometric dimensions. Further, the rubber samples were kept in a relaxed state at an elevated temperature in a surfactant medium during 30-90 min. As a result of modification, low molecular weight polyethylene oxide molecules are adsorbed onto the surface of elastomeric material and further they are diffused into the surface layers due to structural heterogeneity of material. In addition, the modifier is able to diffuse into the volume of material and create a gradient structure differing in the degree of structuring in the surface layer and at some depth. The surfactant medium studied was polyethylene oxide with molecular weight 400. It is non-toxic, has acceptable physical and chemical properties, cease of synthesis and low cost, which makes it promising elastomer modifiers. For comparison purposes we used unmodified press- cured elastomer products and the same elastomer products modified in low-molecular polyethylene oxide. For characterization of network, the most often used is crosslink density  and average molecular weight of rubber segments situated between two crosslinks Mc. These parameters were determined by using the equilibrium swelling method. For the  and Mc calculation the Flory-Rehner equation was used: 2 ln(1Vr ) Vr  Vr     1 3 and M c  , (1) V0 (Vr  0.5Vr )  where Vr is the volume fraction of rubber in equilibrium swolled vulcanizate sample, V0 is the molar volume of used solvent (toluene = 106.3 cm3/mol), χ is the polymer-solvent interaction parameter, and ρ is rubber density [1]. It was found that average molecular mass between crosslinks and crosslink density values of elastomeric compositions depends on time of modifying compositions in polyethylene oxide medium. The network parameters increase with increasing modification time of rubbers in the medium. Thus, the value of crosslink density of rubber modified by 30-90 min varies from 2.29 to 2.62 mol/cm3. At the same time, crosslink density of unmodified rubbers is 2.32 mol/cm3. The change in characteristics of network of modified rubbers may be due to the action of low molecular weight polyethylene oxide in the mixture as a surfactant, which affects the process of forming a rubber network. On the other hand, the intermolecular interaction of polar groups of macromolecules of rubber and polyethylene oxide can also lead to the formation of additional physical bonds.

REFERENCES [1] P.J. Flory, J. Rehner, Statistical mechanics of crosslinked polymer networks. II. Swelling, J. Chem. Phys. 11 (1943) 521. 37

INVESTIGATION OF ELASTIC PROPERTIES OF PRINTS

Simona Grigaliuniene1, Vytautas Turla2,*, Jonas Sidaravicius3, Paulius Ragauskas4, Arturas Kilikevicius5 1, 2, 3, 5Vilnius Gediminas Technical University, 28 Basanavičiaus str., LT-03224 Vilnius, Lithuania 4Vilnius Gediminas Technical University, 11 Sauletekio aw., LT-10105 Vilnius, Lithuania

ABSTRACT

Mechanical (elasticity) properties of prints during printing process and converting are essential. An effective computational inverse technique involving FEM is presented to determine the elasticity properties of prints consisting of paper and ink layer or ink coated with varnish. Methodology is based on experimental data of modal vibration testing and finite element modelling. The aim of finite element modelling and optimization is to predict the material properties obtaining the same vibration frequencies and modes while test specimen is loaded the similar way as in printing press. Proposed technique can be used for the printing process modelling as non-destructive method during the initial design stage, and for the forecasting of the behaviour of the end products. Proposed identification technology of elasticity parameters of material involves vibration testing carried out on an experimental research equipment and mathematical material model. Eigenfrequencies of the sample and the corresponding mode shapes are obtained from vibration test. In the mathematical model elasticity properties are alternated until the eigenfrequencies of the mathematical model correspond with frequencies of vibration testing. Then it is assumed that chosen in such a way elasticity parameters correspond to the real values. Obtained elasticity properties are of the whole specimen but not of the particular layer of the specimen. In order to verify the technology for identification of elasticity properties of prints, numerical experiments are carried out on different materials: plain paper and prints. Prints are varnished additionally; therefore a three layer composite material is obtained. The paper as orthotropic material can be described by six independent elasticity parameters:

E1, E2 = E3, ν12 = ν13, ν23, G12 = G13, G23 = E2 / 2(1 + ν23),

where subscript numbers 1, 2 and 3 indicate paper grain direction (machine direction), cross grain and z-direction accordingly. However, in order to simplify the three-dimensional identification problem to the two dimensional one, the following assumptions are introduced:

E1, E2 = E3, ν12 = ν13 = ν23, G12 = G13 = G23 = E2 / 2(1 + ν12).

FEM uniform rectangular mesh of 10×10 and SHELL63 FE was used. SHELL63 has both bending and membrane capabilities. Both in-plane and normal loads are permitted. The element has six degrees of freedom at each node: translations in the nodal x, y, and z directions and rotations about the nodal x, y, and z axes. The element is defined by four nodes, four thicknesses, elastic foundation stiffness, and the orthotropic material properties. Orthotropic material directions correspond to the element coordinate directions. Frequencies of paper specimen were obtained performing the natural experiment. During numerical analysis of the paper dynamics the known in advance properties of paper were taken: length, width, thickness, Poisson's ratio, modulus of elasticity and density. During identification procedure several modes of specimens were obtained. Due to fact that general properties of elasticity are identified, obtained mode shapes are similar for all samples nevertheless ink coating is different; therefore mode shapes for each specimen are not provided.

EXPERIMENTAL EQUIPMENT

Tests were carried out clamping the two opposite edges of sample. The sample excited with the piezoelectric transducer contacted with the surface of sample, providing a range of frequencies from 10Hz to 1000Hz. Measurements were performed by non-contact method in 15 points, symmetrically arranged on the surface of the sample (4, Fig. 5).

Fig. 5. Scheme of sample clamping and excitation: 1 – sample, 2 – piezoelectric transducer, 3 – pretention force, 4 – measuring points

Sample (1, Fig. 5.) was clamped between two steel guides to ensure proper edge conditions of experiment. Since paper is wobbly due to its thickness such fixing of sample allows controlling dynamic behavior of specimen. Clamps were fixed so they preserve parallelism by using clamps and were subjected to tension force, indicated as F (3). Position of piezoelectric transducer (2) was selected experimentally trying to arouse higher out-of-plane displacements of sample.

Results table Identified elasticity parameters P1 Elasticity Δ, parameters Reference Identified %

E1, GPa 1.1 1.22 10.9

E2, GPa 0.39 0.334 14.3

ν12 0.40 0.39076 2.31

ν23 0.14 - - Objective - 0.0354506 - function

CONCLUSIONS

The possibility to determine the elasticity constants of prints using the combination of finite element modeling and genetic algorithm was shown on previous paper. In this work is verified the repeatability and accuracy of the proposed inverse determination method. The investigation of the two samples of prints also proves that the elasticity properties identification technique is appropriate. Theoretical and practical experiments reviewed in claims that the elasticity properties of print changes in the way that prints turn from orthotropic to isotropic because of ink effects on paper internal structure. This was once more confirmed and proves reliability of the proposed technology for the identification of elasticity properties of prints. It was stated that amount and sequence of eigenfrequencies used in identification process must be selected according identification results.

PRINCIPLES OF SEARCHING FOR THE OPTIMAL DESIGN SOLUTION OF THE LONGITUDINAL HIGHWAY PROFILE

Nadiejda Pavlenko1, a, Gintas Viselga2, b* 1Kharkiv National Automobile and Highway University, Department of Researches and Designing of Highways and Airports, Ukraine 2Vilnius Gediminas Technical University, Department of Mechanical and Materials Engineering, Lithuania E-mail: [email protected], [email protected]

Keywords: longitudinal highway profile, optimal design solution, computer-aided design, technical and economic efficiency.

ABSTRACT

The current regulatory and methodological support for the processes of research, design and construction of roads significantly lags behind many innovative solutions. Among the reasons for this gap there is the lack of a sufficient number of studies and assessments of the effectiveness of innovation, as well as changes in the rules for the design only after proven practice experience. This creates a vicious circle of problems - outdated rules preclude the application of new solutions, and without assessing the effectiveness of these solutions it is difficult to improve the same rules. In practice, the design of the longitudinal profile accepted maximum effect at minimum cost. To date, science has mathematically grounded methods of finding a solution to this problem in this sense as “to the maximum of any one indicator”, as a rule, “does not pay, neither in the maximum nor in the minimum of others”. The article considers the mathematical basis of the optimization and possible ways of finding the criterion of effectiveness of the design solution. The advantages, disadvantages and possible cases of use of a particular criterion of efficiency as an objective function was analyzed.

ARMATURE TYPE INFLUENCE FOR ELECTROMAGNETIC LAUNCHER RAIL

Justinas Račkauskas1, a *,Rimantas Kačianauskas2,b, Markus Schneider3,c 1,2 Department of Strength of Materials and Engineering Mechanics, Vilnius Gediminas Technical University Saulėtekio 11, 10223 Vilnius, Lithuania 3French-German Research Institute of Saint Louis (ISL) 5 rue G’al Cassagnou, 68301 Saint-Louis, France E-mail: a [email protected], [email protected], [email protected]

Keywords: volume force; electromagnetic launcher; distributed armature.

ABSTRACT

The linear EM launcher is a mechatronic device aimed at accelerating small mass equipment and potentially offering the possibility to reach muzzle velocities higher than 2 km/s. The idea of linear Electromagnetic (EM) launcher was put forward in the 19th century. The first efforts to develop an EM launcher were undertaken by Kristian Birkeland in Norway [1]. Over the last 100 years, many experiments have been made in order to improve the launcher design and to create more powerful devices. The mechanical structure of the device presents two electric current-conducting rails and an armature between them [2]. The power supply equipment (e.g. a capacitor and a pulse forming unit) and other components (e.g. switches) are required in order to operate an EM launcher [3]. The extensive research on electromagnetic and mechanical behavior of these devices was performed [4]. In the paper the results are presented of the finite element electromagnetic analysis of a linear electromagnetic launcher and the calculations of electromagnetic force distribution along the rail. We calculate a 3-D distribution of the J×B volume force density in the rails and use them as input for our structural mechanics model. The electromagnetic model was simulated using numerical model which is verified in [5]. The example of calculations presents the J×B distribution of y-component using different type of armature – rail-distributed armature model. In previous model the armature was one copper cuboid in this case armature is four cylinders distributed on the rail surface as visible in Fig. 1. The optical view of force distribution is visible at the inner rail surface and next two pictures indicate the slice view of different positions: region where rail is empty (slice A)) and region with armature (slice B) and B’)). For this calculation was used rail model with different type of armature and main difference is that was calculated half model of full model (in ase with cuboid armature modeling was done with on quarter of model). The model was increased due to symmetry issues during calculations.

Fig.1 The electromagnetic force distribution in the rail with distributed armature

The calculated electromagnetic force was used for mechanical model as a load to investigate the effect of different type of armature. The electrometrical model was simulated using calculating model which is verified in [4]. In the Fig. 2. the displacements of rail surfaces are presented according different 41

load: load with cuboid armature and load with distributed armature. The displacement far away from armature is the same as with cuboid armature. Main difference of displacement frame is different. The amplitude of displacement of both types of armature is the same.

Fig.2 The displacement of rail surface using the volume force load of two different armatures

Numerical results obtained in the performed electromagnetic FE analysis represent the important features of the mechanical volume forces acting over the rails volume of an electromagnetic launcher. The local effect demonstrates the small difference between different type of armatures. The distributed armature requires higher calculation resources, but the impact form mechanical calculation is low.

REFERENCES

[1] I. R. McNab, “Early electric gun research,” IEEE Trans. Magn., vol. 35, no. 1, pp. 250–261, 1999. [2] Richard A. Marshall and W. Yang, Railguns: their science and technology. China Machine Press, 2004. [3] A. Keshtkar, S. Bayati, and A. Keshtkar, “Effect of rail’s material on railgun inductance gradient and losses,” 2008 14th Symp. Electromagn. Launch Technol. EML, Proc., pp. 130–133, 2008. [4] R. Stonkus, J. Račkauskas, M. Schneider and R. Kačianauskas., “Structural Mechanics of Railguns With Open Barrels and Elastic Supports : The Influence of Multishot Operation,” IEEE Trans. Plasma Sci., pp. 1–6, 2015. [5] M. Schneider, J. Račkauskas, and M. J. Löffler, “Electromechanical modeling of components of a linear electromagnetic accelerator,” IEEE Trans. Plasma Sci., vol. 41, no. 10, pp. 2796–2799, 2013.

THE INVESTIGATION OF IRON – BASED CORED WIRES FOR THERMAL ARC SPRAYING

Justinas Gargasas1, Irmantas Gedzevičius2, Gintas Viselga3, Ina Tetsman4, Giedrius Balčiūnas5, Vytautas Turla6, Hanna Pokhmurska7 1-4 Department of Mechanical and Materials Engineering, Vilnius Gediminas Technical University, Vilnius, Lithuania 5 Scientific Institute of Thermal Insulation, Laboratory of Thermal Insulating Materials, Vilnius Gediminas technical university, 6 Department of Mechatronics, Robotics and Digital Manufacturing, Vilnius Gediminas Technical University, Vilnius, Lithuania 7 National University "Lviv Polytechnic", Ukraine

Keywords: thermal arc spraying, cored wires, tribological properties.

ABSTRACT

This paper presents new experimental created iron-based cored wires, for thermal arc spraying, doped with Mn-Cr-Mo-Ni-Mn-Cr-Mo, Mn-Cr system alloying elements, which exhibit exceptional tribological properties of coatings determining the good performance. The main task was to identify the main technological parameters of the spraying parameters and properties of the coatings. Experimental investigation methods were applied for evaluating the thermal arc spraying coatings obtained by the qualitative characteristics in the present research. Tribological properties of coatings were evaluated in accordance with ASTG 65 – 04, ASTMG 75 – 07 standards. Also coatings were evaluated according to sliding wear test. The corrosion properties of coatings were investigated by potentiometric dynamic corrosion tests. Thermal sprayed metallic coatings are extensively used in different branches of engineering to protect the surface of components from wear, corrosion or to restore thickness of details. Thermal spray techniques are grouped according to the type of energy use. One of them is electric arc spraying. In the electric arc spray process (also known as the wire arc process) two consumable wire electrodes connected to a high – current direct-current (dc) power source are fed into the gun and meet, establishing a arc between them that melts the tips of the wires. The molten metal is then atomized and propelled toward the substrate by a stream of air. The process is energy efficient because all input energy is used to melt the metal. The electric arc spraying is the low-cost process with high productivity regarding the preservation of the quality of sprayed layers. Spray rates are driven primarily by operating current and vary as a function of both melting point and conductivity. Electric arc spraying also can be carried out using inert gases or in a controlled – atmosphere chamber. Temperatures within the arc rise to 6500 ºC. High temperature at the wire ends can cause a burning loss of alloying elements in the spray materials. For elements such as silicon or manganese, loss can rise to 40 %, for other elements, e.g. carbon, even up to 50 %. Adapted alloyed bulk or filled wires are therefore necessary. Thermal sprayed metallic coatings are highly capable of improving the superficial wear resistance of industrial components. Wire filler materials, the specific processes and parameters predominantly influence the characteristics and hence the properties of the sprayed coatings. The filler material of wires can be vary various. Usually wires for thermal arc spraying has chromium content ranging from 1 to 5%. That choice was determined by the relatively small cost of wires and good mechanical properties of coatings. Coatings consist of single, flattened particles of different size. There are pores, gas inclusions, unmelted wire material and other contaminations, cracks and interface delamination of different sizes and shapes in the coatings (depending on the specific spray process conditions and materials used). Thermal spray coating has homogenous structure. It may also contain oxide layers and inclusions between the splats. The oxide inclusions form as a result of oxidation of molten metal droplets while in- 43

flight. The oxide layers between the splats are probably the result of both surface oxidation of the molten metal droplets in-flight, and continued oxidation of the splats on the surface as they solidify. The process and feedstock variables influence such chemical and mechanical coating‘s properties as the chemical composition, microstructure, coating adhesion, and toughness profoundly. Therefore, the resulting friction and wear behavior of arc sprayed wear protection coatings are likewise influenced. In addition, the inhomogeneous microstructure of spray coatings strongly influence the coatings’ wear behavior, too. Spray materials and the spray process parameters mainly affect the characteristics and the properties of the sprayed coatings. Large varieties of thermally sprayed coatings were tested to estimate their resistance to dry friction. The investigation results can be used in determining the thermal arc spraying technological parameters' influence on the obtained coatings' mechanical, physical and tribological properties, and by adjusting the spray parameters it is possible to obtain coatings that meet the requirements of specific operating conditions.

REFERENCES

[1] Ajdelsztaj, L.; Zuniga, A.; Jodoin, B.; Lavernia, E. J. 2006. Cold – spray processing of a nano crystalline Al-Cu-Mg-Fe-Ni alloy with Sc., Thermal spray Technology 15: 184–190. [2] Aliofkhazraei, M. 2014. Thermal spray nanostructured ceramic and metal – matrix composite coatings. Anti – abrasive Nanocoatings. Current and future applications. Elsevier Science & Technology: 481–511. [3] Chen, S.; Xiang, J.; Huang, J.; Zhao, X. 2015. Microstructures and properties of double – ceramic – layer thermal barrier coatings of La2(Zr0.7Ce0.3)2O7/8YSZ made by atmospheric plasma spraying, Applied Surface Science 340: 173–181. [4] Chromik, R. R.; Goldbaum, D.; Shockley, J. M.; Yue, S.; Irissou, E.; Legoux, G.; Randall, N. X. 2010. Modified ball bond shear test for determination of adhesion strength of cold spray splats, Surface and Coatings Technology 205(5): 1409–1414. [5] Davim, P. 2012. Materials and Surface Engineering, Research and Development. Woodhead Publishing Limited: 121–162. [6] Renzhong, H.; Ma, W.; Hirotaka, F. 2014. Development of ultra-strong adhesive strength coatings using cold spray, Surface and Coatings Technology 258: 832–841. [7] Rico, A.; Gómez-García, J.; Múnez, C. J.; Poza, P.; Utrilla, V. 2009. Mechanical properties of thermal barrier coatings after isothermal oxidation. Depth sensing indentation analysis, Surface & Coatings Technology 203: 2307–2314. [8] Skopp, A.; Kelling, N.; Woydt, M.; Berger, L.-M. 2007. Thermally sprayed titanium suboxide coatings for piston ring/cylinder liners under mixed lubrication and dry-running conditions, Wear 262(9–1): 1061– 1070. [9] Stewart, S.; Ahmed, R.; Itsukaichi, T. 2005. Rolling contact fatigue of post-treated WC-NiCrBSi thermal spray coatings, Surface & Coatings Technology 190(2–3): 171–189. [10] Sundar, M.; Whitehead, D.; Mativenga, P. T.; Li, L.; Cooke, K. E. 2009. Excimer laser decoating of chronium titanium aliuminium nitride to facilitate re-use of coating tools, Optics & laser technology 41: 938–944.

INCIPIENT BEARING FAULT DIAGNOSIS USING WPT AND ANN INCLUDING PARAMETER OPTIMIZATION

María Jesús Gómez1,a *, Eduardo Corral1,b, Cristina Castejón1,c, Juan Carlos García-Prada1,d 1Universidad Carlos III de Madrid, Avenida de la Universidad 30, 28911, Leganés, Madrid, Spain E-mail: [email protected], [email protected], [email protected], [email protected]

Keywords: vibration analysis, bearings diagnosis, wavelet packets transform, artificial neural networks, parameter optimization. ABSTRACT Bearings are elements with great risk of failure that can affect the whole machine. They are one of the most widely used elements in rotating machinery. Therefore, bearing fault diagnosis has focused the attention of many researches in the last decades. Most of them agree with the use of vibration signals analysis as the most reliable solution for this purpose. Different signal processing techniques have been applied with the aim of detecting bearing faults at incipient stage. This manuscript presents an improved technique of fault bearing diagnosis using vibration signals, in which the features are processed by means of the Wavelet Packet Transform (WPT) and classified by an Artificial Neural Network (ANN). The features are selected using an optimization process, that includes the decomposition level used for the application of the WPT and the packets selected. The optimization is an automated process and involves the training of several ANN with Radial Basis Function architecture. Selected features are those which offer the best diagnosis rates. The improvement is tested using experimental data from a quasi-real industrial machine, shown in figure 1.

Figure 1. Bench used to obtain the experimental data Bearings supported axial and radial loads while rotating at different speeds at steady state: 10, 20 and 30 Hz. A comparison with previous related works shows that the improved technique increases the diagnosis rates. The comparison of results is shown in table 1.

Table 1. Comparison of the success rates and number of neurons in the hidden layer at different speeds with the results obtained in previous reported works with the same data. Current work Reference [1] Reference [2] Speed (Hz) Neurons Accuracy (%) Neurons Accuracy (%) Neurons Accuracy (%) 10 60 96.92 30 91.38 30 85.71 20 87 95.89 19 91.78 30 81.63 30 145 91.38 7 92.58 30 77.04

The hit rates are of 97% for early faults and the system is not only able to detect the faults but also to locate them with very low computational cost.

REFERENCES

[1] M. Gomez, C. Castejon, J. Garcıa-Prada, Incipient fault detection in bearings through the use of WPT energy and neural networks, Advances in Condition Monitoring of Machinery in Non-Stationary Operations. Lecture Notes in Mechanical Engineering (2014) 63–72. [2] C. Castejon, O. Lara, J. Garcıa-Prada, Automated diagnosis of rolling bearings using MRA and neural networks, Mechanical Systems and Signal Processing 24 (2010) 289–299.

ANALYSIS AND NUMERICAL MODELING OF BROKEN AXLE CONSTRUCTION

Živilė Čepukė1,a *, Vitalijus Rudzinskas1,b, Olegas Černašėjus1,c 1Faculty of Mechanics, Vilnius Gediminas Technical University, Department of Materials Science and Welding J. Basanavičius str. 28, 03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: axle, crack, load, numerical simulation, semi-trailer, stress.

ABSTRACT

The semi-trailer axles experience the higher dynamic loads during exploitation. Manufacturers have evaluated that serious damage usually does not occur. However, semi-trailers axles sometimes break before their warranty period. It is good, if the cracks are (observed) and axles are repaired or replaced in time. However, the companies experience huge losses when the cracks have not been fixed in time, which cause the large fractures in semi-trailer axle during the trip. This paper examines the fracture of semi-trailer axles which appeared (during exploitation). The metal structure was analyzed and mathematical model of the axle was developed using finite element method. Practical and numerical simulation results were analyzed and conclusions were presented.

Fig. 1 Broken axle of a semi-trailer

REFERENCES [1] H.V. Katore, A.R. Raghatate, K.A. Bhat, Analysis of existing trolley axle using ANSYS, in International Journal of Science, Environment and Technology, Vol. 4, No 2, India, 2015. [2] S. Aloni, S. Khedkar, Comparative Evaluation of Tractor Trolley Axle by Using Finite Element Analysis Approach, in International Journal of Engineering Science and Technology (IJEST), Nagpur, 2012. [3] Information on http://corporate.safholland.com/en/about-us/products.html [4] LST EN ISO 6520–1:2007. Welding and allied processes - Classification of geometric imperfections in metallic materials - Part 1: Fusion welding. 2007. [5] LST EN ISO 5817:2014. Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) - Quality levels for imperfections. 2014. [6] Ž. Čepukė, J. Tretjakovas, V. Rudzinskas, 2016. Review of fracturing axles of semi–trailers and solutions methods, in Mechanika'2016. Kaunas: Kaunas University of Technology, 2016. ISSN 1822-2951, 62–66.

ESTIMATION OF DAMPING RATIOS OF PEDESTRIAN BRIDGE BY OPERATIONAL MODAL ANALYSIS METHOD

Darius Bacinskas1,a, Arturas Kilikevicius2,b 1Department of Bridges and Special Structures, Vilnius Gediminas Technical University, Vilnius, Lithuania 2Institute of Mechanical Science, Vilnius Gediminas Technical University, Vilnius, Lithuania E-mail: [email protected], [email protected]

Keywords: pedestrian bridge; dynamic testing, free vibration, frequency.

ABSTRACT

Paper presents experimental and numerical investigations of dynamic behaviour of a pedestrian bridge. In this study, it is aimed to compare the modal damping ratios attained by considering frequency range and the method used in modal parameter identification as variable parameters. Both the natural frequencies and the modal damping ratios were obtained from each measurement by using Enhanced Frequency Domain Decomposition (EFDD) and Stochastic Subspace Identification (SSI) techniques. The natural frequencies and their corresponding modal damping ratios were presented and compared with each other for all cases.

REFERENCES [1] J.R. Casas. The Bridges of the Future or the Future of Bridges?, Frontiers in Built Environment 1(2015, April) 1–3. [2] M. Sánchez-Silva, D. M. Frangopol, J. Padgett, M. Soliman. Maintenance and Operation of Infrastructure Systems: Review, Journal of Structural Engineering 142(9): 1-17 (2016). [3] A. Reis, J.J. Oliveira Pedro. Composite Truss Bridges: new trends, design and research, Steel Construction 4(3): 176–182 (2011). [4] C. E. Bakis, L. C. Bank, V. L. Brown, E. Cosenza, J. F. Davalos, J. J. Lesko, A. Machida, S. H. Rizkalla, T. C. Triantafillou. Fiber-reinforced polymer composites for construction - State-of-the-art review, Journal of Composites for Construction 6(2): 73–87 (2002). [5] C. J. Burgoyne, P. R. Head. Aberfeldy Bridge – an advanced textile reinforced footbridge, Techtextil Syposium. 1-9 (1993). [6] T. Stratford. The Condition of the Aberfeldy Footbridge after 20 Years in Service, in Structural Faults and Repair 2012, 3-5 July 2012, Edinburgh, United Kingdom. [7] D. Bačinskas, A. Rimkus, D. Rumšys, A. Meškėnas, S. Bielinis, A. Sokolov, T. Merkevičius. Structural Analysis of GFRP Truss Bridge Model. Procedia Engineering. 12th International Conference on Modern Building Materials, Structures and Techniques (MBMST), 26-27 May, 2016, Vilnius, Lithuania. Amsterdam: Elsevier Science Ltd, 2017. Vol. 172, p. 68-74. [8] C. Heinemeyer, C. Butz, A. Keil, M. Schlaich, A. Goldack, S. Trometer, M. Lukic, B. Chabrolin, A. Lemaire, P. O. Martin, A. Cunha, E. Caetano. Design of lightweight footbridges for human induced vibrations. JRC Scientific and Technical Reports. 1-82 (2009).

FINITE ELEMENT ANALYSIS OF 3D PRINTED SCAFFOLDS

Deividas Mizeras1,a, Algirdas Vaclovas Valiulis1,b, Andžela Šešok2,c, Artūras Kilikevičius3,d, Justinas Gargasas1,e 1Department of Materials Science and Welding, Vilnius Gediminas Technical University, J. Basanaviciaus Str. 28, LT-03224 Vilnius, Lithuania 2Department of Biomechanics,Vilnius Gediminas Technical University, J. Basanaviciaus Str. 28, LT-03224 Vilnius, Lithuania 3Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanaviciaus Str. 28, LT- 03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected] [email protected]

Keywords: 3D scaffolds, design, FEA, mechanical properties, pore size.

ABSTRACT The use of finite element analysis (FEA) as an alternative tool to evaluate the mechanical properties of 3D printed scaffolds is one of the first steps to find optimum 3D porous scaffolds with interconnected porosity and with good mechanical properties. First of all, the simulations and measurements are performed in a non-destructive way. This is important because mechanical properties are extracted without compromising the structure to real mechanical loads. The level of porosity, pore size distribution, pore morphology and the degree of pore interconnectivity in bone grafts significantly influence the extent of bone ingrowth [1]. To calculate porosity would be a important way to assist designing 3D scaffold with optimum characteristics as required for a particular patient in need. Such analysis can be used to vary several geometrical or material parameters at the same time and to choose the most suitable ones for the replacement of natural tissues [2]. Porosity and pore sizes of scaffolds play a critical role in bone formation. Pores are necessary for bone tissue formation because they allow migration and proliferation of osteoblasts and mesenchymal cells, as well as vascularization [3]. Porous scaffolds were designed varying parameters by SOLIDWORKS software. The chosen architectures are defined as woodpiles: geometry, where layer consists of parallel logs which are rotated certain angle every next layer. So, to change the porisity need to change main scaffold parameters: h – log high, b – log width, w – pore size, T - period (b + w) (Fig.1).

Fig. 1. Schematic diagram for scaffold parameters In this work porous scaffolds were designed with various architectures by varying design. Various scaffold architectures can be imprinted by applying various lay-down patterns (0/90, 0/30/60/90/120/150, 0/60/120, and 0/20/40/60/80/100/120/140/160) as shown in Fig. 2

b) a) 0/90 0/20/40/60/80/100/120/140/160

c) 0/60/120 d) 0/30/60/90/120/150

Fig. 2. 3D scaffolds with different architectures: a – logs are rotated 90 deg every next layer, b - each layer is rotated 20 deg in respect to the previous one, c - each layer is rotated 60 deg in respect to the previous one, d - logs are rotated 30 deg every next layer

Finite element modeling usage as an alternative tool to evaluate the mechanical properties of 3D printed scaffold is a good idea, because before the real test can find out which models are superior. Another important advantage is possibility to change the pore size and the final porosity before test.

REFERENCES

[1] Tancred, D.C., et al., A synthetic bone implant macroscopically identical to cancellous bone, Bi-omaterials 1998, 19(1): 2303- 2311. [2] S. V. N. Jaecques, H. V. Oosterwyck, L. Muraru, T. Van Cleynenbreugel, E. D. Smet, and M. Wevers, Individualised, micro CT-based finite element modelling as a tool for biomechanical analysis related to tissue engineering of bone, Biomaterials, vol. 25, pp. 1683-1696, 2004. [3] Kuboki Y, et al., BMP-induced osteogenesis on the surface of hydroxyapatite with geometrically feasible and nonfeasible structures: topology of osteogenesis, J BiomedMater Res 1998, 39(2):190–9.

LOW CYCLE FATIGUE OF ALUMINUM ALLOYS UNDER STRAIN- CONTROLED LOADING

Kurek Andrzej1, Koziarska Justyna2, Łagoda Tadeusz3,* 1,2,3Opole University of Technology, Prószkowska 76, Opole, Poland E-mail: [email protected], [email protected] , [email protected]

Keywords: low cycle fatigue, bending, torsion, tension-compression.

ABSTRACT

The paper presents a comparison of the fatigue life curves based on test of PA4 and PA6 aluminium alloy under cyclic, pendulum bending, pendulum torsion and tension-compression. The data of cyclic bending and cyclic torsion were obtained on new stand with strain controled loading (fig.1) [1]. These studies were analyzed in terms of a large and small number of cycles where strain amplitude is dependent on the fatigue life. It has been shown that commonly used Manson-Coffin-Basquin model cannot be used for tests under cyclic bending and cyclic torsion due to the impossibility of separating elastic and plastic strains. For this purpose,some well-known models of Langer [2] and Kandil [3] and one new model of authors, where strain amplitude is dependent on the number of cycles, were proposed.

Fig. 1. Strain controlled stand for bending loading

REFERENCES

[1] A. Kurek, A. Kulesa, T. Łagoda, M. Kurek, Determination of strain charcteristic under cyclic bending, 11th Interantional Conference Mechatronics System and Materials, MSM 2015, Abstracts, I. Skiedraite, R.Rimasauskiene, L.Zubrickaite, E.Dragasius Eds., Kaunas University of Technology, Kaunas 2015, p.131. [2] B.F. Langer B.F., Design of Pressure Vessels for Low-Cycle Fatigue, ASME Journal of Basic Engineering, Vol. 84, (1962) 389-402. [3] F.A. Kandil, The Determination of Uncertainties in Low Cycle Fatigue Testing, Standards Measurement & Testing Project No. SMT4-CT97-2165, Issue 1, (2000), 1-26.

This work has been carried out under the grant of National Science Centre (Poland) no. 2015/19/B/ST8/01115

DYNAMIC DIAGNOSTICS INVESTIGATIONS OF STEEL WIRE ROPE CONDITION EVALUATION

Audrius Čereška1,a *, Vytautas Bučinskas2,b, Ernestas Šutinys3,c 1 Vilnius Gediminas Technical University, Department of Mechanical Engineering, Basanavičiaus str. 28, LT- 03224, Vilnius, Lithuania 2,3 Vilnius Gediminas Technical University, Department of Mechatronics and Robotics, Basanavičiaus str. 28, LT-03224, Vilnius, Lithuania E-mail: a [email protected], b [email protected], c [email protected]

Keywords: steel wire rope, frequency, dynamic diagnostics, measurements, condition.

ABSTRACT

Steel wire rope of twisted of steel wires are used in: cranes, bridges, architectural objects, conveyor belts, mining, oil and gas, fisheries and sea, forest and communications, ski lifts, elevators, funicular railways and other devices are responsible cargo and lifting persons. As a result, the quality of the steel wire ropes carries high quality requirements. One of these is integrity of the wires, strength of which defines steel rope properties. Exterior steel wire ropes defects can induce catastrophic consequences and make heavy losses to the property and to health of personnel. Defect detection problem of steel wire ropes extensively studied in many research works of the different countries, but it is still looking for methods to do this quickly and efficiently. This paper presents a dynamic diagnostic investigation of steel wire rope condition evaluation, when wire rope twisted from separate wires. Dynamic diagnostic investigation of steel wire rope used to carry out special experimental stand. Experimental investigations were carried according to a special methods. For experimental investigations use three different lengths (1350; 1450; 1550 mm) and three different thicknesses (3.92; 3.96; 4.0 mm) of steel wire ropes. Every tension steel wire rope was excitation harmoniously in the frequency range from 60 Hz to 560 Hz, when excitation step was 50 Hz. The measured vibration amplitude of total steel wire rope and broken wires. Identify defect detection regularities of steel wire ropes. Finally, result of investigation are presented and corresponding conclusions are drawn.

REFERENCES

[1] V. Bučinskas, E. Šutinys, V.K. Augustaitis, Experimental research of steel rope integrity problem, J. of Vibroengin. 13 (2011) 312-318. [2] D. Basak, S. Pal, D. C. Patranabis, Inspection 6x19 seale preformed haulage rope by nondestructive technique. Rus. J. of Nondestruc. Test. 45 (2009) 143-147. [3] D. Basak, S. Pal, D.C. Patranabis, Non-destructive evaluation of a 6x25 fw haulage rope in a monocable continuously moving passenger cable car installation, J. of Engine. and Technol. 1 (2009) 486-490. [4] E. Šutinys, V. Bučinskas, Detecting defects rope using dynamical methods, in the 16th Intern. Conf. “Mech. – 2011” 1 (2011) 301-305. [5] E. Šutinys, V. Bučinskas, A. Dzedzickis, The research of wire rope defect using contactless dynamic method, J. Mechatr. Syst. and Mat. 251 (2016) 49-54. [6] M. Giglio, A. Manes, A life prediction of a wire rope subjected to axial and bending loads, J. of Engine. Fail. Anal. 12 (2005) 549-568. [7] D. Elata, R. Eshkenazy, M.P. Weiss, The mechanical behaviour of a wire rope with an independent wire rope core. J. of Sol. and Struct. 41 (2004) 1157-1172. [8] D.K. Zhang, S.R. Ge, Y.H. Qiang, Research on the fatigue and fracture behaviour due to the fretting wear of steel wire in hoisting rope. J. of We. 255 (2003) 1233-1237. [9] I. Paczelt, R. Beleznai, Nonlinear contact – theory for analysis of wire rope strand approximation in the fem. J. of Comp. and Struct. 89 (2011) 1004-1025.

[10] S.R. Ghoreishi, P. Cartroud, P. Davies, T. Messager, Analytical modelling of synthetic fibber ropes subjected to axial loads. Part i: a continuum model for multi-layered fibrous structures. J. of Sol. and Struct. 44 (2007) 2924-2942. [11] S.R. Ghoreishi, P. Cartroud, P. Davies, T. Messager, Analytical modelling of synthetic fibre ropes subjected to axial loads. Part ii: a linear elastic model for 1+6 fibrous structures. J. of Sol. and Struct. 44 (2007) 2943- 2960. [12] G. Shibu, K.V. Mohankumar, S. Devendiran, Analysis of a three layered straight wire rope strand using finite element method. Proceed. of the word congress on engineering iii. Wce 2011. [13] A.G. Piersol, T.L. Paez, Harris` shock and vibration handbook, sixth ed., New York, 2010. [14] X.Y. Wang, X. B. Meng, J.X. Wang, Y.H. Sun, K. Gao, Mathematical modelling and geometric analysis for wire rope strands, J. of App. Math. Model. 39 (2015) 1019-1032. [15] R. Raišutis, L. Kažys, L. Mažeika, E. Žukauskas, V. Samaitis, A. Jankauskas, Ultrasonic guided wave- based testing technique for inspection of multi-wire rope structures, J. of NDT&E Intern. 62 (2014) 40-49. [16] D. Zhang, M. Zhao, Z. Zhou, S, Pan, Characterization of wire rope defects with grey level co-occurrence matrix of magnetic flux leakage images, J. Nondest. Eval. 32 (2013) 37-43. [17] J. Zhang, X. Tan, P. Zheng, Non-destructive detection of wire rope discontinuities from residual magnetic field images using the hilbert-huang transform and compressed sensing, J. of Sens. MDPI 17 (2017) 1-19. [18] P. Peterka, J. Krešak, S. Kropuch, G. Fedorko V. Molnar, M. Vojtko, Failure analysis of hoisting steel wire rope, J. of Engineer. Fail. Anal. 45 (2014) 96-105.

A SIMPLE APPROACH TO MECHANICAL MODELING OF SINGLE MITRAL VALVE CHORDA

Gediminas Gaidulis1, a*, Rimantas Kačianauskas2, b, Oleksandr Hubanov2, c, Audrius Aidietis3, d 1 Vilnius Gediminas Technical University, Faculty of Mechanics, Department of Biomechanical Engineering, J. Basanavičiaus g. 28, LT-03224 Vilnius, Lithuania 2 Vilnius Gediminas Technical University, Faculty of Mechanics, Institute of Mechanics, J. Basanavičiaus g. 28, LT-03224 Vilnius, Lithuania 3 Vilnius University Hospital Santaros Klinikos, Centre of Cardiology and Angiology, Santariškių g. 2, LT- 08661 Vilnius, Lithuania E-mail: a [email protected], b [email protected], c [email protected], d [email protected]

Keywords: biomechanics, echocardiography, mitral valve, chordae tendineae, hyperelasticity.

ABSTRACT The mitral valve (MV) separates the left atrium (LA) from the left ventricle (LV) and controls the blood flow from the LA into the LV. It is composed of the valve annulus, the valve leaflets (anterior and posterior), the chordae tendineae and the papillary muscles. During diastole, the MV opens as a result of increased pressure in the LA as it fills with blood. Diastole ends with atrial contraction and the leaflets close thus preventing the backflow of the blood into the LA. Mitral valve prolapse is a condition in which the MV does not close smoothly but instead one or both leaflets bulge upward into the LA. This is mostly due to the rupture of the chordae tendineae that support the MV. In some cases, the prolapsed MV lets a small amount of blood flow backwards from the LV into the LA. This disorder is called mitral regurgitation (MR). If mild, MR may not cause problems, however, severe MR can lead to a life-threatening emergency. The severity of MR generally depends on the number and location of the ruptured chordae [1]. Consequently, the rupture of individual chorda may be the initial reason for violation of healthy functioning of the MV. Numerical simulation of the MV based on the patient specific data became common practice in scientific research and medical practice. Recently, the focus on mechanics of chordae is increasing, different finite element models of the MV structure have been built and tested [2, 3] to better understand the behavior of the chordae tendineae. However, such calculations are time consuming and geometry- dependent, as the simulation of the MV function must be performed but the understanding of a single chorda is still insufficient. Therefore, the simplified approach to determine mechanical behavior of the chordae tendineae without the MV simulation is of major practical importance. In this report, evaluation of mechanical load of a single chorda is considered.

Method The movement of the free edges of the MV leaflets and the papillary muscles should be known to simulate a real-time behavior of the chordae. Transthoracic echocardiography (TTE) is usually used for the MV imaging. During diastole, the MV is opened and the chordae are relaxed, so evaluation of their behavior during systole, when the MV closes and the chordae experience high mechanical loads, is of higher importance. The data of the movement of the normal MV at the heart rate of 66 bpm, characterized by a 26 Hz time frequency, was obtained during TTE at Vilnius University Hospital Santaros Klinikos using Philips iE33 ultrasound machine and the QLAB imaging software (Fig. 1). The beginning of systole was chosen as the initial state, since at this point in time the MV starts to close and the chordae are straightened but neither relaxed nor stressed. The positions of both ends of the marginal chorda were manually

determined frame by frame during systole which takes 0.378 s and corresponds to the heart rate of 66 bpm.

Posterio r leaflet

Margina l chorda Papillar y muscle Fig. 1. Ultrasound image of posteromedial view of the MV structure

The geometry of the chorda was created using 2-node linear beam elements. Both linear and nonlinear material parameters were taken into account. For linear response, Young’s modulus of 40 MPa and Poisson’s ratio of 0.45 were adopted [4], while nonlinear behavior was described using Mooney- Rivlin hyperelastic model. The coordinates of the papillary muscle were subtracted from those of the posterior leaflet, eliminating the movement of the end of the chorda connected to the papillary muscle and leaving only the movement of its opposite end. The displacement was calculated and applied to the model and the simulation using Abaqus FEA software was performed.

Results Linear and nonlinear approach showed different behavior of the chorda during systole. Tension at the systolic peak during linear and nonlinear analysis reached 1.56 N and 2.74 N respectively (Fig. 2), which corresponds to the values determined during the simulation of the whole MV structure [5].

Fig. 2. Tension experienced by the chorda during systole REFERENCES

[1] Gabbay, U.; Yosefy, C. 2010. The underlying causes of chordae tendinae rupture: a systematic review, International Journal of Cardiology 143(2): 113–118. [2] Votta, E., et al. 2008. Mitral valve finite-element modelling from ultrasound data: a pilot study for a new approach to understand mitral function and clinical scenarios, Philosophical Transactions of The Royal Society A: Mathematical, Physical and Engineering Sciences 366(1879): 3411–3434. [3] Prot, V.; Skallerud, B.; Haaverstad, R. 2009. Finite element analysis of the mitral apparatus: annulus shape effect and chordal force distribution, Biomechanics and Modeling in Mechanobiology 8(1): 43–55. [4] Kunzelman, K. S., et al. 1993. Finite element analysis of mitral valve, Journal of Heart Valve Disease 2(3): 326–340. [5] Khodaei, S.; Fatouraee, N.; Nabaei, M. 2017. Numerical simulation of mitral valve prolapse considering the effect of left ventricle, Mathematical Biosciences 285: 75–80. 55

MODAL ANALYSIS OF THE OPTICAL TABLE LEVITATING ON MAGNETIC SUPPORTS

Andrius Gedvila1,A*, Artūras Kilikevičius2,B, Vadim Mokšin1,C 1Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224 Vilnius, Lithuania 2Institute of Mechanical Science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: damping, modal analysis, optical table, resonant frequency.

ABSTRACT

The main aim of this research was to experimentally establish modal parameters of the optical table levitating on magnetic vibration isolating supports which design is described in the work [1]. Photo of the experimental setup is presented in Fig. 1. Type 3660-D Bruel & Kjaer portable frame with LAN- XI data acquisition modules connected to Type 8344 piezoelectric accelerometers (their arrangement on the table is presented in Fig. 2) and Dell computer with data analysis software were used to measure and store experimental data.

Fig. 1. Experimental setup: 1 – optical table; 2 – magnetic vibration isolating support; 3 – shaker with vibration amplitude control handwheel; 4 – vibration frequency control panel; 5 – piezoelectric accelerometer; 6 – data acquisition modules; 7 – computer

Fig. 2. Arrangement scheme of piezoelectric accelerometers

Results Some of results are presented in Fig. 3. The upper curve represents 1st mode normalized correlation function versus time graph and the lower graph represents extremal correlation function values used to calculate damping coefficient.

Fig. 3. Results of modal analysis (1st mode)

Parameters of the first four resonance modes are presented in Table.

Table. Results of modal analysis Mode Nr. Frequency, Hz Damping ratio, % 1 6.03 2.8 2 301.8 1.389 3 438 1.271 4 558 0.2027

REFERENCES [1] A. Gedvila, V. Mokšin, FEM investigation of load carrying capacity of magnetic vibration isolating supports, Solid State Phenom. 251 (2016) 94-99.

INVESTIGATION ON THE EFFICIENCY OF USING TECHNICAL MEANS FOR MULCHING POTATO SOILS

Gintas Viselga1, a*, Mindaugas Jurevičius1, b, Justinas Gargasas1, c, Ina Tetsman1, d, Vytautas Turla2, e, Algirdas Jasinskas3, f, Aneta Marczuk4, g, Edmund Kaminski5, h, Evgeniya Ugnenko6, i 1Vilnius Gediminas Technical University, Department of Mechanical and Materials Engineering, Lithuania 2Vilnius Gediminas Technical University, Department of Mechatronics, Robotics and Digital Manufacturing, Lithuania 3Aleksandras Stulginskis University, Institute of Agricultural Engineering and Safety, Lithuania 4Institute of Technology and Life Sciences, Branch in Warsaw, Poland 5Institute of Technology and Life Sciences, Mazovian Research Centre in Kludzienko, Poland 6Kharkiv National Automobile and Highway University, Department of Researches and Designing of Highways and Airports, Ukraine E-mail: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: potato, complex aggregates, mulching, technology, soil, quality indicators, yield, energetic efficiency.

ABSTRACT

A technology of preparation of self-compacting loam soils for potato that applies active working parts and complex aggregates and enables formation of higher furrows under potato crop is investigated herein. In experimental technologies, a rotor cultivator-mulcher with a horizontal rotor and a technological tracking device were used. The efficiency of such technologies may be improved by mulching the soil. It was strived to clear up the positive impact of the new agricultural technique on the quality & energetic indicators of the soil and the potato yield. It was found that it results reduction of the crop weediness and formation of more favourable conditions for growing of potato shrubs. Thus the conditions for operation of harvesters are improved and the yield of a potato shrub is increased. Rotor and chisel working parts are effective in soil preparation for potato planting in spring, because they ensure favorable conditions for potato growing and digging that enable growing higher yields in self- compacting loam soils mulched by oleiferous radish upon lower woodiness. Mulched loam soil is more sensitive to compression. It is impacted by glutinous disintegrated organic matter that binds the soil. Mulching mostly impacts the lumpiness and the soil crumbling indicator, because incompletely disintegrated vegetal remnants affect lump formation in light loam soils. So, in environmentally-friendly potato cultivation according to an experimental technology, every measure to minimize driving on the technological tracks should be taken. In such a way, the environmental pollution by exhaust of internal combustion engines was reduced as well.

MAGNETORHEOLOGICAL MODELLING OF OSCILLATING ENERGY HARVESTER FOR LOW FREQUENCY APPLICATIONS

Sigitas Petkevičius1,a, Vytautas Bučinskas2,b, Andrius Dzedzickis3,c*, Darius Viržonis 4,d, Ernestas Šutinys5,e, Inga Morkvėnaitė-Vilkončienė6,f 1,2,3,4,5,6 Faculty of Mechanical Engineering, Department of Mechatronics and Robotics, Vilnius Gediminas Technical University, J.Basanavičiaus str.28, LT-03224 Vilnius, Lithuania. E-mail: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected].

Keywords: energy harvester, low frequency, magnetorheological.

ABSTRACT

This paper presents research results of a magnetorheological modelling of vibration energy harvester for low frequency applications. This paper represents part of continuous research, which is focused on efficiency increase of low frequencies energy harvesting devices [1, 2]. Purpose of our research is to create equipment which will allow efficiently harvest energy from low frequency (several hertz) vibrations and use it to power the low-power devices, for example position and motion sensors, LED or LCD displays, etc. Most of the harvesters designed until now are using piezoelectric systems [3, 4] or mechanical systems which work in frequencies higher than 20 Hz [4-6]. The main factor, which determines amount of the harvested energy is the sensitivity of the entire system to the low frequency external signal. Our proposed harvester design is based on pendulum type mechanical system and highly efficient electromagnetic energy converter featuring sectorial permanent magnet generator design. Energy harvested by the pendulum system mainly depends on the geometric parameters of pendulum [7-9] and properties of energy converter, which converts mechanical energy to electrical. We aimed to create the digital model of the pendulum type harvester and use it to define optimal geometric parameters with emphasis on highest energy harvesting efficiency at low (1 to 5 Hz) frequencies. Three-dimensional model of a harvester was created using SOLIDWORKS software and then analyzed in COMSOL Multiphysics, using AC/DC toolset for digital modeling of magnetorheological properties. Permanent magnet electromagnetic energy converter was chosen as most reliable option. . We also designed the experimental test rig, which consisted of the case with coils and permanent magnets mounted on the lever, which oscillates about its equilibrium point. Amount of harvested energy was measured using laboratory oscilloscope. Influence of excitation frequency, strength of the permanent magnetic field, resistance of coil wires and other parameters were elevated to verify the COMSOL model. It was shown that our design is suitable to generate the voltage up to 6 Vpp, while the system was excited by the 30 mm amplitude at 1 Hz frequency. Finally, detailed result of research are presented and corresponding conclusions are drawn.

REFERENCES [1] A. Kazickij, V. Bučinskas, E. Šutinys, The research of stiffness characteristics of active elements of harvester. Elec., Electr. and Inform. Sc. (eStream) (2015) 1-4. [2] A. Kazickij, V. Bučinskas, N. Šešok, I. Iljin, R. Subačius, G. Bureika, A. Dzedzickis, Research on implementation of harvester on the cargo wagon. J. of Transp. Probl. 1 (2015) 247-256. [3] L. Zhou, J. Sun, X.J., Zheng, S.F. Deng, J.H. Zhao, S.T. Peng, Y. Zhang, X.Y., Wang, H.B. Cheng, A model for the energy harvesting performance of shear mode piezoelectric cantilever. J. of Sens. and Act. 179 (2012) 185-192. [4] L. Dhakar, H. Liu, F.E.H. Tay, C. Lee, A new energy harvester design for high power output at low frequencies. J. of Sens. and Act. 199 (2013) 344-352. 59

[5] V. Janicek, M. Husak, 3D Energy Harvester Evaluation. J. of Radioengin. 22 (2013) 251-258. [6] K. Tao, S. Liu, S.W. Lye, J. Miao, X. Hu, A three-dimensional electret-based micro power generator for low-level ambient vibrational energy harvesting. J. of Micromech. and Microeng. 24 (2014) 1-11. [7] S. Roundy, P.K. Wright, J. Rabaey, A study of low-level vibrations as a power source for wireless sensor nodes. J. of Comp. Com. 26 (2003) 1131-1144. [8] V. Bučinskas, A. Dzedzickis, N. Šešok, E. Šutinys, I. Iljin, Modelling of double-pendulum based energy harvester for railway wagon. J. of Advanc. in Intel. Syst. and Comp. 543 (2017) 64-74. [9] V. Bučinskas, A. Dzedzickis, N. Šešok, E. Šutinys, I. Iljin, A. Kazickij, Two-axis mechanical vibration harvester. J. Dynam. Syst. Mechatr. and lif. Sc. 1 (2015) 99-110.

KINEMATICS AND DYNAMICS OF THE QUASI-PASSIVE ROBOT WALKING “PASIQUAD”

Eduardo Corral1, Jesús Meneses1, María Jesús Gómez Garcia 1, Juan Carlos García-Prada1 1 University Carlos III de Madrid. Department of Mechanical Engineering. MAQLAB.

Keywords: mechanism analysis, quasi-passive, walking robots, quadruped. ABSTRACT A quasi-passive four legged walking robot (having only one motor/actuator) called “PASIQUAD” is presented in this article. The manuscript is focused into the PASIQUAD’s topology, kinematics and dynamics, and the program designed for carrying out the corresponding calculations. This code provides for all kinematic and dynamic data, as functions of time, along one step: position, velocity and acceleration of all members, as well as all the forces and torques on each of them, motor torque included. This latter information will help us to choose the required motor, as this choice depends on some parameters of interest that can be modified in the program, like density or link dimensions. Also, we will be able to get strain-stress data in all links in the course of a step, and then optimize those dimensions. To finish, some results are also presented that confirm the interest of the developed code.

RESEARCH OF CU-NB MICROCOMPOSITE WIRES WELDED JOINTS

Gediminas Mikalauskas1,a,*, Nikolaj Višniakov2,b, Raimonda Lukauskaitė3,c, Jelena Škamat4,d 1,2,3,4 Vilnius Gediminas Technical University, Vilnius, Saulėtekio 11, LT-10223, E-mail: [email protected], [email protected], [email protected], [email protected]

Keywords: Cu-Nb microcomposites, welding joints, electric cable, electrical contact connection.

ABSTRACT

Compact impulse magnet installations can generate record magnetic fields up to 100 T. Impulse magnetic systems are quite simple in their construction and use low electrical power, therefore are popular in various fields of science and industry [1]. The key element of such magnetic systems is the solenoid. The most popular are multi-layer winded solenoids. The materials of conductors of such solenoids must be very strong and have good electrical conductivity. Magnetic fields over 45 T can be generated only in the form of short impulses, therefore the electric cables shall stand extreme impact and cyclic heating. For those purposes presently composite wires of 4 new types are used: Cu-Nb and Cu- Ag microcomposites, GlidCop, GlidCuSS macrocomposites [2, 3, 4]. Cu-Nb microcomposite is presently considered as the best-fit of all above-mentioned types because of the whole set of its unique properties. The strength of such wire is about 1,5 GPa, when electric conductivity is 67-70 % IACS. This material is useful in different magnetic installations, but also in levitation transport, high-voltage power lines, induction welding, industrial equipment of thermal treatment. Presently the construction of solenoids of the most magnetic equipment is sectional, therefore it needs many contact connections [5, 6, 7]. In electrical engineering, wire and cable connections may be destructive (screw) and nondestructive (welded, soldered and pressed). Nondestructive joints are preferable in such case, since microcomposite wires are characterised as of limited capability for deformation. Besides, after magnetic systems are entered into operation, access to all connections is very limited. All contact connections shall not be the weakest chain of systems [8]. So far in practice only the screwed and soldered conductor connections, which do not demonstrate sufficient reliability and long service time in terms of impact and cyclic heating, are used [9, 10]. Therefore, the welded joints are advanced and more reliable. The complexity of selection of welding technologies for those purposes occurs due to the Cu-Nb microcomposites structure and production specifics, as well as conditions of exploitation. The structure of microcomposites Cu-Nb consists of copper matrix where very thin Nb treads are integrated [11, 12, 13]. The technology of Cu-Nb microcomposite production is similar to the process of multi-stage pressure or diffusion bonding, when Cu-Nb wire is obtained by multiple plastic deformations of materials. Fusion welding methods for connection of microcomposite wires may not be used because of inevitable microcomposite melting, overheat of the joined wires and the loss of unique properties. Therefore, one of the most important unsettled problems in the techniques of strong magnetic fields is creation of a reliable welded connection of microcomposite conductors. This problem theoretically may be solved using special methods of welding. In this work we presented the experimental results of Cu- Nb wire joining applying the different technologies and analysis of nondestructive joints properties.

REFERENCES

[1] Herlach F., Miura N. High Magnetic Fields. Magnet Technology and Experimental Techniques. Science and Technology. Vol. 1. London: Imperial College Press, 2003, 336 p.

[2] Shneerson G. A., Dolotenko M. I., Krivosheev S. I. Strong and Superstrong Pulsed Magnetic Fields Generation. De Gruyter Studies in Mathematical Physics, 2006, p. 147-178. [3] Han K., Embury J. D., Sims J. R., Campbell L. J., Schneider-Muntau H. J., Pantsyrnyi V. I., Shikov A., Nikitin A., Vorobieva A. The Fabrication, Properties and Microstructure of Cu-Ag and Cu-Nb Composite Conductors Material Science and Engineering. Vol. 267, 1999, p. 99 – 114. [4] Brandao L., Han K., Embury J. D., Walsh R., Toplosky V., Van Sciver S. Development of High Strength Pure Cooper Wires by Cryogenic Deformation for Magnet Applications IEEE Transactions of Applied Superconductivity, Vol. 10 (1), 2000, p. 1282 – 1287. [5] Blumber L., Hasizume H., Ito S., Minervini J., Yanagi N. Status of high temperature superconducting magnet development. RSFC/JA-10-45 report, 2010, 3 p. [6] Jones H., Van Cleemput M., Hickman A. L., Ryan D. T., Saleh P. M. Progress in High-Field Pulsed Magnets and Conductor Develoment in Oxford Physica B, vol. 246, 1998, p. 337 – 340. [7] Ciazynski D., Duchateau J., Decool P., Libeyre P., Turck B. Large superconductors and joints for fusion magnets. From conceptual design to testing at full scale. Nuclear fusion, Vol 41, Nr. 2, 2001, IAEA: p. 223- 226. [8] Višniakov N, Novickij J, Ščekaturovienė D, Petrauskas A. Quality Analysis of Welded and Soldered Joints of Cu-Nb Microcomposite Wires. Materials Science, Vol. 17(1), 2011, p. 16-19. [9] Hwan Kyun Yeo, Kwan Hee Han. Wetting and spreading of molten SnPb solder on a Cu–10%Nb microcomposite. Journal of Alloys and Compounds. Volume 477, Issues 1-2, 2009, p. 278–282 [10] Shikov A.K., Pantsyrnyi V., Vorobeva A., Sudev S., Khlebova N, Silajev A., Belyakov N. Copper-niobium high strength and high conductivity winding wires for pulsed magnets. Material science and Heat Treatment, Vol. 44, Nos. 11-12, 2002, p. 491-495 [11] Leprince-Wang Y., Han K., Huang Y., Yu-Zhang K. 2003. Microstructure of Cu-Nb microcomposites. Material science and engineering. A351, 2003, p. 214-223 [12] Głuchowski W., Stobrawa J.P., Rdzawski Z.M., Marszowski K. Microstructural characterization of high strength high conductivity Cu-Nb microcomposite wires, Journal of Achievements in Materials and Manufacturing Engineering 46/1, 2011, p. 40-49. [13] Robert W., Messler Jr. Principles of Welding: Processes, Physics, Chemistry, and Metallurgy, Wiley-VCH Verlag GmbH, Weinheim, 2004, 662 p.

INVESTIGATION OF ELASTIC PAPER PROPERTIES USING MODAL ANALYSIS

Artūras Kilikevičius1, a *, Nikolaj Šešok2, b, Igor Iljin2, c, Rimantas Stonkus2, d 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania 2,3,4 Department of Mechatronics, Robotics and Digital Manufacturing, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected] * corresponding author

Keywords: paper properties, modal analysis, roller interactions, elasticity properties, vibrational methods, finite element modelling.

ABSTRACT

REFERENCES [1] Ragauskas, P., S Ragauskas, P., Skukis, E. (2007). Material properties identification. Comparison of two techniques, Mechanika, vol. 6, no. 68, p. 39-44. [2] Ragauskas, P., Belevičius, R. (2009). Identification of material properties of composite materials. Aviation, vol. 13, no. 4, p. 109. [3] Ragauskas, P. (2010). Identification of elastic properties of layered composite materials, Doctoral dissertation, Technika, Vilnius. [4] Kulachenko, A., Denoyelle, T., Galland, S., Lindstrom, S.B. (2012). Elastic properties of cellulose nanopaper. Cellulose, vol. 19, p. 793-807. [5] Yokoyama, T., Nakai, K. (2007). Evaluation of in-plane orthotropic elastic constants of paper and paperboard, in proceeding of 2007 SEM Annual Confere [6] Pintelon, R., Guillaume, P., Vanlanduit, S., Belder, K. D., Rolain, Y. (2004). Identication of young's modulus from broadband modal analysis experiments. Mechanical Systems and Signal Processing, vol. 18, p. 699-726.

STRUCTURAL CHARACTERISTICS OF ZRC/NI-UDD COATINGS DEPOSITED ON A TUNGSTEN CARBIDE CUTTING TOOL

V.V. Chayeuski1, a *, V.V. Zhylinski1,b, O. Černašėjus2,c, N. Višniakov2,d, R. Lukauskaitė2,e 1Belarusian State Technological University, Minsk, 13а, Sverdlov str., 220006, Belarus 2Vilnius Gediminas Technical University, Vilnius, 28, Basanaviciaus str., 03224, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: chromium carbide, coating, Ni- ultradisperse diamonds, tungsten carbide, microstructure, PVD, SEM, cutting tools.

ABSTRACT Transition metals nitride and carbide hard coatings have been applied to protect cutting tools against damage in various industrial fields. The tungsten carbide (WC) ligated with cobalt is one of the modern solutions for cutting tools The hard coatings possess attractive properties, sush as greater wear resistance, and chemical stability. However, some traditional hard ceramics, such as nitrides, carbides, borides, and oxides (TiAlN, TiC, TiB2, etс.) do not have the capability to retain their properties under heavy cutting conditions. The life time of carbide tools can be considerably improved by the nanostructured multilayers coatings such as TiCN, TiCrN, AlCrN, CrZrN, etc. synthesized by the physical vapor deposition (PVD) process, and are found to possess superior mechanical properties [1, 2]. The use of ultradisperse diamonds (UDD), obtained by detonation of explosives, as a composite in electrochemical and chemical metal-diamond coatings also leads to an increase in their wear resistance, significant adhesion, and a significant decrease of the friction coefficient [3]. Treatment of hard alloy knives with the combined electroplating and PVD methods proved to provide increase of durability period of the ZrN-Ni-Co-coated cutting tools for laminated chipboard milling [4]. In this work, a cathode arc evaporation physical vapor deposition (CAE-PVD) and electroplating processes were used for the deposition of ZrC/Ni-UDD coating on the tungsten carbide cutting inserts. The microstructure, phase and elemental composition of the ZrC/Ni-UDD coating are studied and reported. The compositional electrolytic coating with nikel matrix and nanodiamonds of detonation synthesis (Ni- UDD) was deposited from the chloride electrolyte at current density ranging from 1 to 10 A/dm2 at the temperature 40–50°C. The method included carrying out the process of the electrolyte deposition containing nickel ions and insoluble hard and superhard particles (UDD with the size up 5 nm) with concentration from 2–5 g/l in suspension. The ZrC coating was deposited by CAE-PVD on the hard alloy samples with Ni-UDD layer in two stages. At first, the surface of specimens was treated with zirconium ions for 1 min at a negative bias of 1 kV and the cathode arc burning current of 100 A. Then, coating was precipitated for 10 min at –1 СН4 pressure in the chamber was 10 Pa under a bias of -120 V. The prepared sampls were characterized through X-ray diffraction (XRD), Scanning electron microscopy (SEM) equipped with Energy dispersive X-ray (EDAX) spectroscopy. The SEM images of the ZrC/Ni-UDD coating are shown in Fig. 1(a) and (b). Fig. 1(a) shows the cross- sectional view of the coating, which reveals that the individual coating thickness obtained for ZrC (Top layer) and Ni-UDD (Bottom layer) are 1.75 µm and 1.50 µm, respectively. The chemical composition of the tungsten carbide ligated with cobalt is shown in Tab. 1.

Table 1. Chemical composition of the tungsten carbide Element C O Co W Сoncentration [weight %] 11.51  1.5 1.45  0.3 2.02  0.1 85.02  3.0

In Fig. 1(b), EDAX spectroscopy was employed to ascertain the morphology and composition of the coated surface. The surface morphology of the coating shows a pattern with pits, pores, and dots (particles). These aspects are characteristics of the CAE-PVD deposition due to its high rate mass deposition.

a b Fig. 1. Microstructure of the ZrC/Ni-UDD coating: (a) cross-sectional views of the coating, (b) microstructure of the coated surface

The elemental composition of the ZrC/Ni-UDD coating top layer is shown in Tab. 2.

Table 2. Elemental composition of the ZrC/Ni-UDD coating top layer Element C O Ni Zr Сoncentration [weight %] 14.88  2.5 3.61  0.8 1.13  0.1 80.38  3.6

Analysis of the elemental composition of the ZrC/Ni-UDA surface of the coating (Tab. 2) shows that the ZrC layer covers densely the Ni-UDD coating and the substrate. To determine the Ni-UDD layer, additional studies were carried out to ascertain the concentration distribution of of the insert surface elements with ZrC/Ni-UDA coating, which confirmed the presence of the Ni-UDD layer, as well as the separate phases of nickel, ZrC zirconium carbide. The XRD pattern showed that the ZrC/Ni-UDA coating consists of separate phases of ZrC, α-Ni, Ni-ultradisperse diamonds phase and ultradisperse diamonds phase similar to the graphite phase. The pilot tests of ZrC/Ni-UDA coated cutting tools while milling laminated chipboard found out increasing of durability period in 1.3 times if compared with bare tool.

REFERENCES [1] A. A. Matei, et al., Structural characterization and adhesion appraisal of TiN and TiCN coatings deposited by CAE-PVD technique on a new carbide composite cutting tool, J. Adhesion Sci. Tech. 29(23) (2015) 2576-2589. [2] T. Sampath Kumar, S. Balasivanandha Prabu, G. Manivasagam, Metallurgical Characteristics of TiAlN/AlCrN Coatings Synthesized by the PVD Process on a Cutting Insert, J. Mat. Eng. Perf. 23(8) (2014) 2877-2884. [3] V. Yu. Dolmatov, Detonation synthesis ultradispersed diamonds: properties and applications, Rus. Chem. Rev. 70(7) (2001) 687-708. [4] V. Chayeuski, V. Zhylinskiy, A. Grishkevich, P. Rudak, Š. Barcik, Influence of high energy treatment on wear of edges knives of wood-cutting tool, MM Sci. J. 6 (2016) 1519-1523.

DESIGN AND NUMERICAL ANALYSIS OF THE ROBOT END–EFFECTOR IN THE FORM OF HUMAN HAND

Sławomir Grycuk1, a *, Roman Trochimczuk 1,b, Iwona Gruszczyńska1,c 1 Bialystok University of Technology, Faculty of Mechanical Engineering, Poland 15-351 Bialystok, Wiejska Str. 45C E-mail: [email protected], [email protected], [email protected]

Keywords: bionic prosthesis, mechatronics, robotics, cad, numeric simulation.

ABSTRACT

The robot’s end–effector in the form of human hand should allow to grasp any object with great accuracy, proper force and dynamics [1, 2]. That is why modern robotics is becoming an interdisciplinary field that combines mechanics, computer science, electronics and materials science [3]. Modern biomechanical end–effectors have to reproduce or mimic in the best possible manner the way of movement and retrieving information from the environment. Contemporary hand prosthesis can be controlled by commands from the human central nervous system [4]. At the same time, information about the position of the fingers, the force of pressure, or the movement of objects in the hand is also transferred. In the human brain electrochemical processes are taking a place that reflects electrical impulses of amplitude closely related to the tasks performed, which are then read by numerous sensors. When these signals are translated into the instructions for the prosthesis, human is able to control with his mind movements of the robot [5]. The aim is to create a lightweight and cheap mioelectric prosthesis of effector with shape of human hand obtained from 3D scan with reverse engineering that allows the most accurate imitation of the action, accuracy and force of the real hand in a synchronized manner, and to allow for independent movement of the thumb and fingers [6]. Compact and simple construction allows for rapid prototyping, and easy operation. It allows to control the robot with a small number of motors and combines them to reduce the EMG electrodes used to control the motion. This is an innovative concept of the human hand shaped effector with use of proprietary finger movement mechanism. The phalanges motion is enforced by one engine, with a set of rod of appropriate length in a suitable attachment in every second hand element with exception of standard attachments in between movable elements imitating joints. The movement of the thumb is resolved by using two motors with wormers, placed perpendicular to each other and connected to each other by a coupler, with a double–sided worm wheel [7]. The paper also deals with the problem of the hand effector and literature and patents were reviewed. An own solution for robots performing precise operations was proposed. The mechanism and drive of the fingers movement and the method of fixing the end–effector were selected. For this purpose were done: a review of literature and patents on human hand shaped robotic effectors, design assumptions for the author's solution, followed by a project in the CAD engineering software environment, and basic mechanical research using CAE tools (SolidWorks and Ansys) were carried out. Numerical analyses have also been carried out, taking into account load, deformations and tensions according to Huber von–Mises'es hypothesis, examination of kinematics and dynamics of the proposed mechanism. Further research directions on the project were also presented [7, 8].

REFERENCES

[1] G. Carbone, Grasping in Robotics, Volume 10, Springer, Italy, 2013 [2] B.B. Edin, L. Ascari, L. Beccai, S. Roccella, J.-J. Cabibihan, M.C. Carrozza . Bio-inspired sensorization of a biomechatronic robot hand for the grasp-and-lift task, “Brain Research Bulletin”, 2008, Vol. 75, pp. 785-

795,[Online]:https://www.researchgate.net/publication/5457224_Bioinspired_sensorization_of_a_biomec hatronic_robot_hand_for_the_grasp-and-lift_task [10.06.16]. [3] E. Khatib, B. Siciliano – Springer Handbook of Robotics, chapters: 15, 27, 28, Springer, 2008. [4] J. Burcan, M. Łuczak, B. Prosnak, Czynna ręka protezowa i jej główne układy kinetyczne, Łódź, 1999. [5] R. Tadeusiewicz, Inżynieria Biomedyczna. Księga współczesnej wiedzy tajemnej w wersji przystępnej i przyjemnej, UWNT AGH, Kraków, 2008. [6] Di Pino G., Guglielmelli E., Rossini P.M., Neuroplasticity in amputees: Main implications on bidirectional interfacing of cybernetic hand prostheses, “Progress in Neurobiology” 2009, Vol. 88. [7] S. Grycuk, The project of bionic prosthesis hand, WM PB Engineering work, 2017 (promoter Ph.D., Eng. Roman Trochimczuk). [8] M. Erdogan, Finite Element Method and Applications in Engineering Using ANSYS, Springer-Verlag, New York, 2015.

INFLUENCE OF THE SPECIMEN’S MATERIAL AND SHAPE ON BEHAVIOR OF THE FATIGUE TEST STAND MZGS100

Lagoda Tadeusz1a, Marta Kurek1,b, Robak Grzegorz1,c, Pawliczek Roland1,d,* 1Faculty of Mechanical Engineering, Opole University of Technology, Mikolajczyka st. 5, 45-271, Opole, Poland E-mail: [email protected], [email protected], [email protected], [email protected],

Keywords: fatigue test, harmonic oscillator, simulation model.

ABSTRACT

This paper presents operation of the Fatigue test stand MZGS100 type, which was developed for fatigue tests of specimens made from constructional materials subjected to combined bending and torsional loading [1]. Investigated stand present a structure of harmonic oscillator [2] and can be described as second order system with oscillations y(t):

2 2 y  2y   y  k u(t) (1) where: ω – natural periodicity, ς – damping ratio, k – gain, y(t) and u(t) – output and input signal respectively. Using simple test base on registered impulse response of the system the parameters of the dynamic model of the analyzed stand were investigated. Taking into account a development process of the structure for such stands, especially due to control system, a modelling and simulation seems to be important part of prototyping and investigations for its operation. It should be noted that the parameters mentioned above depend on the properties of the test materials and the shape of the samples used for the tests. The main goal of this paper is to define the influence of the specimen’s material and shape on the characteristics of the MZGS stand. Figure 1 presents a set of specimens, which are used for fatigue test with the stand. Specimens characterizes with cylindrical and diabolo shape and they are made of two types of a low-alloy high- strength steel (1,3,4), aluminum alloy (2) and brass (5).

3 4

Fig. 1. The specimens 5

The damping curves for acquired impulse response are shown in Fig. 2. To compare damping effect all response’s time series were scaled to range (0,1).

1.2 Specimen damping ratio natural Experimental damping curves periodicity 1 for specimens: No ζ ω 1 2 1 0.0032 32.2 0.8 3 2 0.0036 26.6 4 5 3 0.0029 29.8

o no specimen

, 0.6 4 0.0028 29.6

a y 5 0.0029 34.6 0.4 no specimen 0.0128 23.5

0.2

0 0 1 2 3 4 5 t,s

Fig. 2. Impulse responses for specimens and parameters for mathematical model

In the general case we can observe a big difference for damping curves of the specimens comparing to the case, where specimen in broken (articulated bar). Meanwhile the differences of the damping ratio between specimens seems to be not so significant. The transient period for analyzed specimens is shown in Fig. 3 to express the influence of changes in natural frequency, which is strongly connected with stiffness of the system.

1.6 Transient period for specimens: 1 2 1.2 3 4 5

n 0.8

0.4

0 0 0.4 0.8 1.2 1.6 2 t,s Fig. 3. Impulse responses for specimens and parameters for mathematical model

This indicate the influence of this parameter on the control algorithm (controller parameters), especially for “point-by-point” analyze. The control system behavior should consider the influence of the object.

REFERENCES [1] T. Łagoda at all, Non-standard fatigue stands for material testing under bending and torsion loadings, Mechatronic Systems and Materials MSM 2015, Abstract, Kowno 2015, pp 130. [2] R. Pawliczek, Z. Marciniak, Investigation of transient period of the working unit for displacement generation in MZGS-200E fatigue stand, Mechatronic Systems and Materials MSM 2014, Abstract, Opole 2014, pp 160-161.

NUMERICAL SIMULATION INTERACTION OF AEROSOL PARTICULUTE AGGLOMERATES IN ACOUSTIC FIELD

Darius Vainorius1, a *, Rimantas Kačianauskas 1, b , Algirdas Maknickas 1, c 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania E-mail: [email protected], [email protected] [email protected] * corresponding author

Keywords: acoustic, agglomeration, particulate, aerosol, DEM.

ABSTRACT

Acoustic agglomeration is a process in which intense sound waves produce relative motions among fine mostly the micron-sized solid aerosol particles, where they touching each other form agglomerates. Acoustic agglomeration has recently been the focus of theoretical and experimental research to increase agglomeration efficiency of micron-sized particles. The understanding of particle behaviours in particulate flows is interesting from environmental engineering and theoretical points of view. The authors will demonstrate in this study the potential of DEM to analyse acoustic wake agglomeration, to improve the understanding of the acoustic wake between two particles. Interaction of mono and poly-sized spherical microparticles in the presence of gravitation is addressed. The uthors will employ this study in future works, for the analysis of multy-particle acoustic agglomeration.

REFERENCES

[1] D. Zhou, Z. Luo, J. Jiang, H. Chen, M. Lu, M. Fang (2016). Experimental study on improving the efficiency of dust removers by using acoustic agglomeration as pretreatment, Powder Technol,. 289, 52–59. [2] S. Pshenai-Severin (1959). On the convergence of aerosol particles in a sound field under the action of the Oseen hydrodynamic forces, Dokl. Akad. Nauk SSSR, 125, 775–778. [3] I. González, J.A. Gallego-Juárez, E. Riera (2003). The influence of entrainment on acoustically induced interactions between aerosol particles - An experimental study. Journal of Aerosol Science, 34 (12), 1611– 1631. [4] G.X. Zhang, J.Z. Liu, J. Wang, J.H. Zhou, K.F. Cen (2012). Numerical simulation of acoustic wake effect in acoustic agglomeration under Oseen flow condition, Chinese Sci. Bull., 57, 2404–2412. [5] T.I. Zohdi (2016). A discrete element and ray framework for rapid simulation of acoustical dispersion of microscale particulate agglomerations, Comput. Mech., 57, 465–482. [6] D. Markauskas, R. Kačianauskas, A. Maknickas (2015). Numerical particle-based analysis of the effects responsible for acoustic particle agglomeration, Adv. Powder Technol., 26, 698– 704.

SIMULATION OF TEMPERATURE AND THERMAL DEFORMATION FIELDS OF MULTILAYERED STRUCTURE

Remigijus Guobysa, Vladas Vekterisb, Vadim Mokšinc*, Gintas Viselgad Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected]

Keywords: fire resistant multilayered structure, fire test, steel, stone wool, temperature, thermal deformations, numerical model.

ABSTRACT

Multilayered structure (fire door) consisting of two parallel steel sheets separated by stone wool (its density was 33 kg/m3) layer was chosen as object of investigation. First steel sheet had a thickness of 1.5 mm, second – 0.7 mm. Thickness of stone wool layer was 50 mm. Structure was reinforced with 1.5 mm thick vertical inner steel stiffening rib located in the middle of the structure. Because of the asymmetry of investigated structure, two fire doors (Fig. 1, a) were installed into a brick wall (200 mm thick) as shown in Fig. 1, b. Before the fire test the wall with installed specimens was then hermetically fastened to the furnace as it is shown in Fig. 1, b. The structure was also investigated numerically using SolidWorks® Simulation software.

a) b) Fig. 1. Investigated multilayered structure (a, shown from both sides) and pictures of the wall with specimens fastened to the furnace (b): 1–26 – temperature measuring points; D1–D11 – deformation measuring points

Simulation and Experimental Results Temperature field computer simulation results are presented in Fig. 2. Experimental results are shown in Fig. 3. From these figures it can be seen that simulation results coincide with experimental results. Thermal deformation measurement results are presented in Table 1 and Table 2.

Fig. 2. Distribution of temperature in investigated structure (temperature at measuring points 1-5 (Fig. 1, a) versus time graph is presented in separate window). Results obtained from SolidWorks® Simulation software

Fig. 3. Temperature at measuring points 1–5 (Fig. 1) as function of time. Results of direct measurements

Table 1. Deformations of the left (from the viewer‘s perspective) door (Fig. 1, b) measured at deformation measuring points (Fig. 1, a) at the end of the 60 min fire test Measuring point D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 Deformation [mm] -25 -19 3 1 8 27 -20 -18 4 3 16

Table 2. Deformations of the right (from the viewer‘s perspective) door (Fig. 1, b) measured at deformation measuring points (Fig. 1, a) at the end of the 60 min fire test Measuring point D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 Deformation, mm 22 18 12 -1 0 38 12 11 10 -5 -3

Conclusions 1. Differences between temperatures obtained from simulation and experiments are only about 2– 8%. 2. Obtained results show that thermal behaviour of investigated multilayered structure can be investigated numerically, thus avoiding costly and time-consuming laboratory experiments.

A COMPARATIVE STUDY OF POLYDIMETHYLSILOXANE (PDMS) FOR PREDICTION OF HYPERELASTIC PROPERTIES: APPLICATION TO SILICONE-RUBBER AND SOFT TISSUES

Artūras Kilikevičius1, a *, Darius Vainorius1, b, Algirdas Maknickas 1, c 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected] * corresponding author

Keywords: hyperelastic properties, soft tissues, polydimethylsiloxane, computational, experimental.

ABSTRACT

The correct modelling of constitutive laws is of critical importance for the analysis of mechanical behaviour of solids and structures. Hyperelastic models depend on sets of variables that must be obtained experimentally. In this study the authors use a computational/experimental scheme, for the study of the nonlinear mechanical behaviour of biological soft tissues under uniaxial tension. The material constants for a different hyperelastic materials models are obtained via inverse methods. This study intents also to select which material models (or model types), the authors will employ in future works, for the analysis of human soft biological tissues.

REFERENCES [1] Humphrey, J. D. (2003) Continuum biomechanics of soft biological tissues. Proc. Math. Phys. Eng. Sci. (Ser. A) 459, 3–46. [2] Azar, F. S., Metaxas, D. N. and Schnall, M. D. (2001) A deformable ﬁnite element model of the breast for predicting mechanical deformations under external perturbations. Acad. Radiol. 8, 965–975. [3] Ogden, R. W., Saccomandi, G. and Sgura, I. (2004) Fitting hyperelastic models to experimental data. Comput. Mech. 34, 484–502. [4] Kauer, M. (2001) Inverse Finite Element Characterization of Soft Tissues With Aspiration Experiments. PhD Thesis, Swiss Federal Institute of Technology, Zurich, Switzerland. [5] Yin, H. M., Sun, L. Z., Wang, G. and Vannier, M. W. (2004) Modeling of elastic modulus evolution of cirrhotic human liver. IEEE Trans. Biomed. Eng. 51, 1854–1856. [6] Areias, P. M. A., Natal Jorge, R. M., Barbosa, J. T., Fernandes, A. A., Mascarenhas, T., Oliveira, M. and Patrıcio, B. (2003) Experimental and ﬁnite element analysis of human skin elasticity. In: American Society of Mechanical Engineers, Bioengineering Division, 55, 303–304.

INVESTIGATION OF THE INFLUENCE OF ACOUSTIC FIELD ON VAPOR PRECIPITATION OVER PLATING BATH

Ina Tetsmana, Vladas Vekterisb, Vadim Mokšinc* Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: aerosol, lateral exhaust hood, acoustic coagulation, sound frequency, sound level.

ABSTRACT Proposed experimental study allows to assess the aerosol acoustic coagulation by indirect parameter, namely by air humidity measured at different temperatures over the plating bath exposed to different frequency and intensity acoustic waves. The experimental setup was designed and manufactured to investigate the influence of acoustic field on the efficiency of push-pull ventilation system. Photo and scheme of the stand is presented in Fig. 1. Liquid (water) 2 is heated in the tank 1 by means of heater 3 and its temperature is measured by temperature gauge 4. Lateral exhaust hood 5 removes aerosols rising from the surface of the liquid. Exhaust hood was attached to edge of the tank 1 and connected with the fan 6. Flow rate of the removed air can be adjusted by the frequency inverter 7. Air blower and sound generator 8 can be used as air blower to create push air flow or as air blower and sound generator as the same time. In the last case, air flow used to generate standing acoustic wave used as push air flow. Air blower and sound generator was mounted over the evaporating liquid so that created air flow is directed on the surface of the liquid. Compressed air is supplied to the air blower 8 through the valve 9; its pressure is measured by pressure gauge 10. In order to measure parameters of the acoustic field hydrophone 11 was used which data was processed by data storage device 12 and computer 13. Air humidity was measured by moisture psychrometer 14 and the results were transmitted to computer 15.

Fig. 1. Experimental setup: 1 – open surface tank; 2 – liquid (water); 3 – heating element; 4 – thermometer; 5 – lateral exhaust hood; 6 – fan; 7 – inverter drive; 8 – air blower and sound generator; 9 – valve; 10 – pressure gauge; 11 – hydrophone; 12 – data storage device; 13, 15 – computer; 14 – psychrometer

Results and Discussion The following parameter of acoustic field generated by air blower and sound generator was analyzed: sound pressure level versus frequency (Fig. 2). In case if compressed air under 4–5 bar pressure was supplied to the air blower, the sound pressure level greater than 120 dB (minimum required value for acoustic coagulation of droplets [1]) was obtained at frequencies 2.6 kHz and at the frequency interval from 3.1 to 3.4 kHz (Fig. 2, b).

Fig. 2. Sound pressure level versus Fig. 3. Relative air humidity measured at different frequency temperatures of the liquid During aerosol removal efficiency studies the changes of air humidity over the evaporating fluid were investigated depending on the temperature of the liquid. Experiments were carried out under the following conditions: - vapor is raised freely from the liquid surface and all vapor removal equipment (exhaust hood and air blower and sound generator) is turned off; - vapor is removed from the liquid surface by lateral exhaust hood enhanced by push air flow from air blower; - vapor is removed from the liquid surface by lateral exhaust hood using air blower that generates push flow and acoustic waves. Fig. 3 presents air humidity measurement results. It can be seen from Fig. 3 that the maximum reduction of concentration of water vapor in air can be achieved in presence of acoustic field when air humidity values are high. In other words the higher initial concentration of aerosol particles in the air results in more effective precipitation process.

Conclusions 1. The aerosol coagulation process is influenced not only by initial concentration of particles, but also by frequency and intensity of sound waves. 2. After analyzing results of measurements of sound pressure of aeroacoustic air flow, it was found that sound generator generates 139.8 dB sound pressure level at 3128 Hz. 3. It is experimentally established that presence of acoustic field improves aerosol removal efficiency of push-pull ventilation system most significantly at increased initial concentration of aerosol particles.

REFERENCES [1] V.N. Khmeliov, Multifunctional Ultrasonic Devices and Their Application in Small Production Enterprises, Agriculture and Household, Barnaul, Altai State Technical University, 1997. 76

SIMULATION AND TENSILE TESTING OF TOPOLOGICALLY OPTIMIZED CERVICAL IMPLANTS MADE BY ADDITIVE MANUFACTURING IS COMPARABLE

Schnitzer Marek1, a *, Kula Tomáš2,b , Hudák Radovan3,c, Bocko Jozef4,d, Živčák Jozef 5,e, Zubko Pavol 6,f, Karásek Michal 7,g Szedlák Peter 8,h 1Department of Biomedical Engineering, Faculty of Mechanical Engineering, TUKE, Košice, Slovakia 2 Department of Applied Mechanics and Mechanical Engineering, Faculty of Mechanical Engineering, TUKE, Košice, Slovakia 3 Department of Biomedical Engineering, Faculty of Mechanical Engineering, TUKE, Košice, Slovakia 4 Department of Applied Mechanics and Mechanical Engineering, Faculty of Mechanical Engineering, TUKE, Košice, Slovakia 5 Department of Biomedical Engineering, Faculty of Mechanical Engineering, TUKE, Košice, Slovakia 6 Institute of Materials Research, Slovak Academy of Sciences, Košice, Slovak Republic 7Clinic of Traumatology at Louis Pasteur University Hospital, Košice, Slovakia 8Klinik für Neurochirurgie – Kopf und Schädelbasiszentrum, Vivantes Klinikum Neukölln, Berlin, Germany E-mail: a [email protected], b [email protected], c [email protected], d [email protected], [email protected], f [email protected], g [email protected]; h [email protected]

Keywords: Topological Optimization, Cervical Implant, Additive Manufacturing, FEA, Simulation, Ti6Al4V.

ABSTRACT

The article focuses on testing and simulations of tensile strenghth of topologically optimized design and additivelly manufactured cervical implants. The proposed platform design comes from anatomical and biomechanical requirements for application of an implant in the cervical area. Thanks to new ways of production, such as Additive Manufacturing, and new software possibilities in the field of structural analysis, which use the finite element method, it is possible to execute topological optimization of an implant in a design, which would be impossible to make by conventional methods. The resulting design of the implant after modification must fulfil the strict criteria of a medical application in the area of the cervical spine with respect to material and mechanical characteristics. The contribution of this work lies in the creation of a methodology of numerical modelling of the static loading of implants in the area of the cervical spine and subsequent experimental confirmation of the correctness of the modelling.

Aim of the study

The proposed platform design of the cervical implant is based on the anatomical and biomechanical parameters of the cervical spine and is currently being used in surgical procedures, in the so called spinal fusion, aiming to replace the damaged intervertebral disc or for fusion of the individual segments of the vertebra. These implants are currently created with conventional manufacturing technologies, e.g. milling, in cases of metal implants or by plastic injection. These implants are usually created as monoliths without the possibility to manufacture internal structures which creates the opportunity for topological optimization based on numerical analysis and subsequent implementation for manufacturing with the use of Additive Manufacturing technology – 3D printing that makes the manufacturing of internal structures possible. Within the scope of the topologically optimized design, this study attempts to prevent the Stress shielding effect (the implants is substantially more dense than its surroundings for its application) which is in spinal fusion displayed as the subsidence of the implant based on experimentally calculated parameters. The proposed platform design is based on the anatomical and biomechanical parameters in the area of the cervical spine.

In addition, the study compares experimentally measured values of, in our case, Ti6Al4V material with numerically calculated values of the given material from the material library of the software.

Fig. 2 Cervical cage Platform Design (left), cross - section (middle), wall thickness analysis (right)

The topologically optimized design is built on FEM calculation executed in NASTRAN software and experimental tested data executed on tensile testing equipment that will be explained in greater detail in the full text.

Fig. 3 Cervical cage optimized Design (left), cross - section (middle), wall thickness analysis (right)

Results

The article dealt with experimental testing of topologically optimized Ti6Al4V cervical implants and comparison to numerical simulation based on FEA. There were 35 prototypes produced by additive manufacturing device Mlab Cusing R (Concept Laser GmbH, Germany), each of which underwent tensile testing that ended with the destruction of the sample. The purpose of this testing was to gain the true material properties of the alloy. Subsequently, these values were used to create numerical computations that simulated the process of the generated tension fields in the implant as a result of a load factor. Based on analysis and data processing it was concluded that the true average yield strength of the material is Re = 852.3 MPa, while the yield strength listed in the material library is Re = 805 MPa. It can be concluded that values are comparable and properly set tensile testing simulation can be a tool for implant design verification. Difference in results is caused by the manufacturing technology which can be viewed positively as it allows the designer to work with a certain degree of freedom and to optimize the design more appropriately for the given problem. In comparison to platform design topollogically optimized design has less weight and it is more flexible with sufficient strenght. The assumption is with topologically optimized cervical implant the effect of subsidence will be minimized.

REFERENCES

[1] K. Wang: The use of titanium for medical applications in the USA, Mat. Sci. Eng., A213 (1996), pp. 134– 137 [2] Steffen T, Tsantrizos A, Fruth I, Aebi M. Cages: designs and concepts. Eur Spine J. 2000;9(1):S089–94.

[3] Kandziora F, Pflugmacher R, Schäfer J, Born C, Duda G, Haas NP, et al. Biomechanical comparison of cervical spine interbody fusion cages. Spine. 2001;26(17):1850–7. [4] Chen Y, Wang X, Lu X, Yang L, Yang H, Yuan W, et al. Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: a prospective, randomized, control study with over 7-year follow-up. Eur Spine J. 2013;22(7):1539–46. [5] ŽIVČÁK, Jozef – HUDÁK, Radovan: Biomechanizmy.Prešov : ManaCon, 2001. 343 s. ISBN 80-89040- 06-3. [6] Bocko, J., Segľa, Š.: Numerické metódy mechaniky tuhých a poddajných telies. 1. Vydanie. Košice: Technická univerzita v Košiciach, 2016. 248 s. ISBN 978-80-553-3065-5, EAN 9788055330655. [7] IVANČO, V., KUBÍN, K., KOSTOLNÝ, K.: Metóda konečných prvkov I. 1. vydanie. Košice : Elfa, 1994. 80 s. ISBN 80-967131-4-0.

ACKNOWLEDGEMENT

This work was supported by research grants: - APVV Slovak Research and Development Agency-15-0356, 07/2016 – 06/2019 Analysis of the PEEK polymer and the additive manufacturing possibilities - Design and technology support in the diagnostics of components and engineering units by means of computer tomography (ITMS No. 26220220038)

INVESTIGATION OF ACOUSTIC GENERATORS

Vladas Vekterisa, Darius Ozarovskisb, Vadim Mokšinc* Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: acoustic generator, frequency, sound pressure.

ABSTRACT Six aerodynamic acoustic field generator prototypes (Fig. 1) were developed and produced. Prototypes were experimentally investigated to determine the following parameters of generated acoustic field: sound pressure and frequency.

AAG-1 AAG-2

AAG-3 AAG-4

AAG-5 AAG-6 Fig. 1. Schemes of acoustic generators

AAG-1 consists of coupling 1, core 2, housing 3 and the nozzle 4. Compressed air flow enters into the generator through coupling 1 and then is distributed by core 2 to the central 5 and peripheral channels 6. Peripheral channels 6 direct the air into the resonance chamber 7. After the pressure in resonant chamber 7 reaches the certain critical pressure, compressed air flow breaks through the air flow passing the central channel 5 and leaves through the nozzle 4. After the outburst air pressure in the resonance chamber 7 is decreased and air flow starts to pass through central channel 5 and come out through the nozzle 4 until the pressure in resonance chamber 7 reaches certain value. Described cycle is repeated creating air flow pulsation and acoustic field as a result. 80

AAG-2 consists of coupling 1, housing 2, nozzle 3 with two rings 4. Compressed air flow is fed through coupling 1 in the primary chamber 5. Then compressed air enters into the secondary chamber 6 of acoustic generator through the diverging hole 7. Due to the hole with increasing diameter 7 air vortexes and pressure fluctuations are created in the chamber 6. Two air flows (primary and secondary) are created in the secondary chamber 6 resulting from the turbulence. These flows come out through the hole 8 of the nozzle 3. Pressure fluctuations of outgoing compressed air flow generate high-frequency acoustic field. AAG-3 consists of coupling 1, diffuser 2, cover 3 and the nozzle 7. Compressed air flow is supplied through coupling 1 into the diffuser 2. Then air flow bypassing the tab 5 of the diffuser enters into the nozzle 7 through slots 4. Due to the holes 6 additional air is ejected into the nozzle 7 which is mixed with the main flow of compressed air. Tab 5 and stepped narrowing of the nozzle 7 cause the turbulent flow. Mixed air flow passing through the nozzle 7 generate acoustic field. AAG-4 consists of couplings 1 and 3 and the nozzle 2. Compressed air flow through the coupling 1 enters into the central channel 4. In addition, the secondary compressed air flow is supplied through coupling 3 which flows the cylindrical channel 5 and cross the main flow near the end of the nozzle 2. The intersection of two compressed air flows causes the pressure pulsations which generate high- frequency acoustic field. AAG-5 consists of couplings 1 and 2, housing 3 and the nozzle 4. Compressed air flow is supplied through coupling 1 into central channel 5 and is directed toward the nozzle 4. In addition, the secondary air flow is supplied through coupling 2 into the housing 3. This air flow enters the central channel 5 through the inclined channels 6 that direct it opposite to the main flow. Due to the inclined channels 6 intersecting opposed flows create pressure pulsations and generate high-frequency acoustic field leaving the nozzle 4. AAG-6 consists of the nozzle 1, resonator 2 with resonance chamber 3. Compressed air flow coming out of the nozzle 1 periodically fills the resonator 2. Then air burst coming out from the resonator collide with compressed air exiting from the nozzle 1. Density fluctuations are generated as a result that generate high pressure acoustic field.

Results Bruel & Kjaer compact sound level meter Type 2250-S was used for measurements of parameters of acoustic field. Results are presented in Fig. 2. It can be seen from Fig. 2 that AAG-6 acoustic generator is the most powerful of all tested. It can be also noticed that the sound pressure peak generated by this acoustic generator is repeated every 8 kHz, i. e. at 8 and 16 kHz. AAG-6 prototype was chosen to be used to generate sound waves in acoustic cyclone separator.

Fig. 2. The sound pressure levels of acoustic field generated by acoustic generators

FUZZY CONTROLLERS IN FIELD ORIENTATION CONTROL SYSTEM OF SIX-PHASE INDUCTION MOTOR

Roma Rinkevičienė1, a*, Zita Savickienė2, b, Saulius Lisauskas3, c, Andrius Petrovas4, d, Donatas Uznys5, e, Aurelijus Pitrėnas6, f, Alvydas Šlepikas7, g 1, 2, 3, 4, 5, 6, 7Department of Automation, Vilnius Gediminas Technical University, Naugarduko str. 41, LT-03227 Vilnius, Lithuania E-mail: a [email protected], b [email protected], c [email protected], d [email protected], e [email protected], [email protected], g [email protected]

Keywords: six-phase induction motor, indirect field oriented control, PI controllers, fuzzy controllers.

ABSTRACT

The paper presents MATLAB Simulink model of symmetrical six phase motor controlled by six phase frequency converter and analyses its performance in indirect vector control mode. Model of the field oriented control for six-phase motor is elaborated with PI and fuzzy controllers and simulation results are compared. The multiphase motors divide the controlled power on more converter legs and reduce the current of power electronic switches as well as in the larger number of electric motor phase windings. This advantage of multiphase motors lead to solve the main problem of minimization and miniaturization of actuators. The multiphase induction motors have advantages over three phase motors, investigated in [1, 2]: lower torque pulsations at high frequency, higher power per rms ampere ratio for the same machine volume, reduced the torque ripples in converter fed drives. The detailed overview state-of-the art in multiphase electric drives area is presented in the articles [1, 2, 3, 4]. The applicability of multiphase systems is explored in electric-ship propulsion, locomotive traction, industrial high-power applications, electric and hybrid-electric vehicles, electric aircrafts, high power compressors, extruder pumps. Generalized mathematical model of six-phase machine presented in [5] is valid for any displacement angle of stator windings sets and cage rotor. Dynamic equivalent circuit includes mutual stator leakage inductance due to different sets of stator windings occupying the same slot. A dq mathematical model derived in [6] is applicable for all multi-phase motors and does not include mutual stator leakage inductance. Simulink model gives possibility to solve nonlinear differential equations fast and allows comparing parameters at different load or control mode. Matlab/Simulink model of six-phase induction motor in synchronous reference frame is presented in [7, 8]. Inputs of the model is direct ' ' current voltages vqs1 and vqs2 , voltages vds1 and vds2 as well as vqr and vdr are assumed equal to zero. Outputs of the model are produced electromagnetic torque and speed. Similar models are ideal models and do not reflect influence of control system power converters and other control system elements usually operating in real electric drive systems. Simulink library does not contain six-phase converter models and switching blocks necessary to elaborate pulses for converter, producing six-phase output voltages, shifted by 60 electrical degrees. This problem we solved with two three-phase converters, using Clark transform for two sets of three phase voltages with different initial phase angles  having values of zero and -60 electrical degrees. The Clark transform is used separately for two voltage sets vAs , vBs , vCs and vDs , vEs , vFs . Then for six-phase converter model we can use two conventional three-phase Simulink blocks named “Converter 1” and “Converter 2” controlled by conventional blocks ”Vector control 1” and “Vector control 2”. Converter 1 elaborates voltages shifted by 0, -120, -240 electrical degrees with respect to reference axis. Converter 2 is tuned to produce the other set of voltages , , shifted by -120 electrical degrees apart with phase voltage 0 vDs lagging the voltage by 60 . 82

Figure 1 presents the Simulink model of field orientation control for six-phase motor with fuzzy controllers. The fuzzy controller is used to replace PI or PD controller in field oriented control system. The fuzzy sets are designated by the labels: NL (negative large), NM (negative medium), NS (negative small), ZE (zero), PS (positive small), PM (positive medium), and PL (positive large). 49 rules comprise each fuzzy controller. The simulation results with fuzzy controller presented in Fig. 2–4: torque, developed by the motor (Fig.2), motor speed (Fig. 3) and six phase currents (Fig. 4). At time instant t  0.6 s load torque of 1Nm is applied. With well-designed fuzzy controllers motor speed at this instant have no any change with load, but torque and currents react on increased load.

i , i , i A B C g + + A Rotating to Stacionary - B Eq. 8 Eq. 10 Six-phase DC source C stationary to A, B, C - motor model Converter1

* T e * Torque T e Speed w feedback w Pulses 1 Load Torque Fuzzy Speed w i , i , i controller A B C Vector control 1 Load Speed + g D Speed Rotating to Stacionary iA, iB, iC, stationary reference E Eq. 13 Eq. 15 to D, E, F iD, iE, iF - F Converter 2 Speed  * * iD, iE, iF T e T e feedback w Speed w feedback w PulsesP 2

Fuzzy iD, iE, iF controller Vector control 2 Fig.1. Simulink model of six-phase motor with Fuzzy controllers.

15 80 4

10 60 2

0 5 40

Currents, A -2

Speed, rad/s Torque, Nm 0 20 -4 0 0.5 1 -5 0 Time, s 0 0.5 1 0 0.5 1 Time, s Time, s

Fig. 2. Transients of torque with Fig. 3. Speed transients with Fig. 4. Transients of six-phase fuzzy controller fuzzy controller motor currents with fuzzy controllers REFERENCES

[1] R. Bojoi, F. Farina, F. Profumo, A. Tenconi, “Dual-three phase induction machine drives control” – A survey,” in Proc. IEEE IPEC, pp. 90–99, CD-ROM, 2005. [1] M. Jones and E. Levi, “A literature survey of state-of-the-art in multiphase AC drives,” in Proc. Conf. Rec. UPEC, pp. 505–510, 2002. [2] E. Levi, R. Bojoi, F. Profumo, H. A. Toliyat, S. Williamson, “Multiphase induction drives – a technology status review”, IET Electr. Power Appl., 2007, 1 (4), pp. 489-516. [3] G.K. Singh, “Multiphase induction drive research – a survey”, Electr. Power Syst. Res., No 61, pp.139– 147, 2002. [4] Singh G K., Pant V., Sing Y.P. Voltage source inverter driven multi-phase induction machine. Computers and Electrical Engineering 29 (2003), 813-834. [5] T.A. Lipo. “A d-q model for six-phase induction machines” in Proc. Int. Conf. Electrical machines (ICEM), Athens, Greece, 1980, pp. 860-867. [6] R. Rinkevičienė, B. Kundrotas, S. Lisauskas, “Model of controlled six phase induction motor”, World Academy of Science, Engineering and Technology, vol. 7, No 1, Zurich, pp. 217–221, 2013. [7] R. Rinkevičienė, B. Kundrotas, S. Tolvaišienė, "Model of Six-Phase Induction Motor", Solid State Phenomena, Vols. 220-221, pp. 510-514, 2015.

FAULT DIAGNOSTICS OF ROLLING ELEMENT BEARINGS OF ROTOR SYSTEMS EQUIPPED WITH VIBRATION DAMPERS

Vladas Vekteris1,a, Andrius Trumpa1,b, Vytautas Turla2,c, Vadim Mokšin1,d*, Gintas Viselga1,e 1Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224, Vilnius, Lithuania 2Department of Printing Machines, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: fault diagnostics, centrifugal milk separator, vibration signal analysis, correlation.

ABSTRACT Damped rotor-bearing system of centrifugal milk separator was chosen as an object of experimental investigations. Accelerometer arrangement is shown in Fig. 1. Experimental setup was adapted for both direct and indirect bearing vibration measurements. In the first case, the vibration acceleration of outer bearing ring 2 is measured by accelerometer 1 (Fig. 1). In the second case, housing vibrations are measured by means of accelerometer 3 attached to separator housing. In order to compare results, vibration measurements were performed for both healthy and faulty bearings used in rotor-bearing system of the separator.

Fig. 1. Centrifugal milk separator (bowl shell is not shown): 1, 3 – accelerometer; 2 – outer bearing ring

Vibration velocity frequency spectra obtained for 112.4 Hz rotational frequency of the rotor are presented in Fig. 2. It can be seen from Fig. 2, a that the differences between vibration velocity amplitudes of faulty bearing and healthy bearing occur in the whole frequency range in the case of direct measurements. In the case of indirect measurements, velocities differ at high frequencies only, i. e. in the frequency range from 1000 Hz to 5000 Hz (Fig. 2, b).

a) b) Fig. 2. Vibration velocity spectra: a) – obtained from bearing vibration measurements, b) – obtained from housing vibration measurements, 1 – case when faulty bearing is used in rotor-bearing system, 2 – case when healthy bearing is used in rotor-bearing system

Correlation function plots are presented in Fig. 3. Calculated correlation coefficients show a weak correlation between vibration velocities of healthy and faulty bearings. Pearson correlation coefficient is equal to 0.34166 and Spearman correlation coefficient is equal to 0.04746. So, it can be stated that statistical relationship is weak. It shows that the vibration levels are different and it can indicate bearing fault. However, there is a good correlation between housing vibration velocities in cases when healthy bearing and faulty bearing were used in rotor-bearing system. Pearson correlation coefficient is equal to 0.85954 and Spearman correlation coefficient is equal to 0.72366. In this case, a good correlation shows the significant impact of damping system.

a) b) Fig. 3. Correlation function between vibration velocities of healthy bearing and faulty bearing: a) – bearing vibration measurements, b) – housing vibration measurements

Conclusions Indirect diagnostic vibration measurements (through the housing) in comparison with direct measurements are not informative if rotor-bearing system of centrifugal milk separator is equipped with vibration dampers. It is proposed to use direct rolling element bearing vibration measurement method to improve the reliability of diagnostic measurements. Its application based on information about bearing parameters allows to make a decision about the condition of rotor-bearing system in cases when the decision can’t be made based on the results of indirect vibration measurements. 85

INVESTIGATION OF POLISHING CHARACTERISTICS FOR ASPHERICAL LENSES MANUFACTURING

Nerijus Kadzevičius1,a, Ieva Švagždytė2,b, Justinas Gargasas3,c, Mindaugas Jurevičius4,d, Artūras Kilikevičius5,e 1, 2, 4, 5Department of Mechanical Engineering, Vilnius Gediminas Technical University, J.Basanavičiaus str. 28, LT – 03224, Vilnius, Lithuania 3Department of Materials Science and Welding, Vilnius Gediminas Technical University, J.Basanavičiaus str. 28, LT – 03224, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: aspherical lenses, form deviation, polishing, surface roughness.

ABSTRACT

Long time in industry conventional spherical lenses were used only, but new types of lenses were created during innovation processes. One of lenses of such types are aspherical lenses. Two main parameters describing quality of aspherical lenses are accuracy of the form shape and surface roughness. These parameters can be obtained after last operation – polishing. Technical parameters that give the biggest influence to form shape and surface roughness were investigated in this experiment and optimal technical parameters for polishing process were established. Melted quartz ,,UVFS” used in this research, investigations were carried out according by full factorial design. Five axis CNC machine Schneider SCPA100 was used for polishing and profilometer Nanoscan 855 was used for measuring. After analysis of results it was found out that speed of rotation and penetration depth are the most important factors in polishing process. For getting the best shape it’s necessary to use the smallest chosen values of speed of rotation and penetration depth and for surface roughness polishing parameters changing conversely. The smallest value of surface roughness Rz was 0.06 µm, and shape deviation was 2.6 µm. Analysis of research was made. Optimal polishing parameters for the best quality of aspherical lenses is provided.

REFERENCES [1] N.Belkhir, T.Aliouane, D.Bouzid, Correlation between contact surface and friction during the optical glass polishing. App. Surf. Science 288 (2014) 208–214. [2] N.Belhir, A.Chorfa, D.Bouzid, Compression behavior of polyurethane polishers in optical polishing process. Int. J. Adv. Manuf. Technol. 86 (2016) 2595–2601. [3] D.Bo, Z.Jianwei, L.Yuling, S.Mingbin, Z.Yufeng, Surface roughness of optical quartz substrate by chemical mechanical polishing. J. Semicond. 35 (2014) 116001. [4] D.Bouzid, N.Belkhie, T.Aliouane, Optical glass surfaces polishing by cerium oxide particles. IOP Conf. Series: Mat. Sc. and Eng. 28 (2012) 012007. [5] Y.Feng, H.Cheng, H.Y.Tam, Mapping error correction of large off-axis aspheric surface in null test. Optik 126 (2015) 5825–5829. [6] J.P.Lee, K.P.Hong, M.W.Cho, S.H.Kwon, H.J.Choi, Polishing characteristics of optical glass using PMMA- coated carbonyl-iron-based magnetorheological fluid. Smart Mater. Struct. 24 (2015) 065002. [7] J.W.Lee, Y.K.Cho, M.W.Cho, G.H.Kim, T.J.Je, Optical Transmittance Recovery of Powder Blasted Micro Fluidic Channels on Fused Silica Glass Using MR Polishing. Int. J. of Prec. Eng. And Manu. 13-11 (2012) 1925-1930. [8] Y.Namba, A.T.H.Beaucamp, A.Matsumoto, R.Freeman, Fluid Jet and Bonnet Polishing of Optical Moulds for Application from Visible to X-Ray. Proceedings of SPIE (2011) 8126. [9] R.K.Pal, H.Garg, R.V.Sarepaka, V.Karar, Experimental Investigation of Material Removal and Surface Roughness during Optical Glass Polishing. Mat. and Manu. Proc., 31 (2016)1613–1620.

[10] S.S.Park, C.H.Cho, Y.Ahn, Hydrodynamic analysis of chemical mechanical polishing process. Trib. Int. 33 (2000) 723–730. [11] X.Shi, G.Pan, Y.Zhou, Z.Gu, H.Gong, C.Zou, Characterization of colloidal silica abrasives with different sizes and their chemical–mechanical polishing performance on 4H-SiC (0 0 0 1). Appl. Surf. Sc. 307 (2014) 414–427. [12] H.Y.Tam, H.B.Cheng, Y.W.Wang, Removal rate and surface roughness in the lapping and polishing of RB-SiC optical components. J. of Mat. Proc. Techn. 192–193 (2007) 276–280. [13] C.Wang, Z.Wang, Q.Wang, X.Ke, B.Zhong, Y.Guo, Q.Xu, Improved semirigid bonnet tool for high- efficiency polishing on large aspheric optics. Int. J. Adv. Manuf. Technol. 88 (2017) 1607–1617. [14] C.Wang, X.Yang, B.Zhong, Z.Wang, Y.Guo, Q.Xu, Effect of the inflated-pressure to the tool influence function for polishing using SR bonnet. SPIE Proceedings (2014) 9281. [15] Information on http://www.jmp.com/support/help/Full_Factorial_Designs.shtml

INVESTIGATION OF FLOW GENERATED IN THE EJECTOR

Vladas Vekterisa, Andrius Styrab, Vadim Mokšinc*, Gintas Viselgad, Mindaugas Jurevičiuse, Ina Tetsmanf Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, 03224, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]

Keywords: ejector, flow density, acoustics, coagulation.

ABSTRACT The pulsating flow ejector [1] can be used in water treatment systems, where water is saturated with oxygen before being treated. It also can be used in other industries, such as chemical and biotechnology, where it is necessary to saturate fluids with gases under variable fluid flow rate condition. Scheme of ejector is shown in Fig. 1.

Fig. 1. The pulsating flow ejector [1]

Fluid under pressure is supplied to fluid chamber 5 (Fig. 1) and then tangentially enters the mixing chamber 3 through holes 13 to generate a swirling flow. Due to the inclination of axes of holes 13, rotating flow is directed towards the bottom wall 8 of chamber 3. When the flow reaches the bottom wall 8, additional turbulence is generated by bulges 10. As the bulge height is variable and decreases towards the axis of rotation of the flow 7 (or the axis of cylindrical mixing chamber 3), the turbulence intensity remains constant along the edge of bulge 10 (Fig. 1). Swirling flow bypassing the bulge 10 creates the negative pressure over the holes 12, which connects mixing chamber 3 with ejecting medium (air) chamber 9. Under the action of negative pressure, ejecting medium begins to enter chamber 3 through holes 12 and mix with fluid due to the generated turbulence. As the density of mixture is changed, the dynamic pressure of the flow is changed as well as the ratio of dynamic and static pressures. When the static pressure increases, swirling flow moves towards the diffuser 2 thus closing the access of fluid to mixing chamber 3 through holes 13. The static pressure drops as a result of this movement, the dynamic

pressure increases proportionally and fluid gains access to mixing chamber 3 again. The cycle is repeated with frequency up to 20 kHz depending on the pressure of fluid and dimensions of mixing chamber 3. Numerical simulation of generated flow was carried out using SolidWorks Flow Simulation 2011 software. Water flow pressure in the ejector, mixing chamber volume and distance L (Fig. 1) were varied during the simulation. From the results obtained the case was chosen when the density variations cause the maximum pressure pulses (Fig. 2). The examination of Lighthill’s equation based on dimension theory [2] allows to calculate sound power level of the flow:

 2 8 2   0 v0d  Lw  10lg k0 , (1)  5   W0c  where v0 is the outflow velocity, 0,  are the density of the flow exiting the nozzle and the density of -5 -5 the surrounding medium, k0 is the coefficient which value varies from 3·10 to (1.5–2.5)·10 , c is the -12 speed of sound in water, W0 = 10 W is the basic sound power. After inserting into Eq. (1) numerical simulation results, we obtain the sound power level from 80 to 120 dB which represents sound intensity from 10-4 W/m2 to 1 W/m2. This exceeds the minimum value required for effective acoustic coagulation.

Fig. 2. Flow density distribution map Conclusion Calculations have shown that the sound power level generated by the flow in the ejector is varied from 80 to 120 dB satisfying the acoustic coagulation conditions.

REFERENCES [1] V. Vekteris, A. Styra, V. Striška, A. Kilikevičius, Republic of Lithuania Patent LT6011B (2014). [In Lithuanian]. [2] M.J. Lighthill, On sound generated aerodynamically: I. Turbulence as a source of sound, Proc. R. Soc. A 222 (1954) 1-32.

DESIGNING AND OPTIMISATION OF FIXING SYSTEMS IN A WELDING TOOL OF INDUSTRIAL ROBOT

W. J. Klimasara1, a, M. Pachuta2,b, Z. Pilat3,c *, M. Słowikowski 4, d 1, 2, 3, 4Przemysłowy Instytut Automatyki i Pomiarów PIAP, Al. Jerozolimskie 202, 02-486 Warszawa, Poland E-mail: [email protected], [email protected], [email protected], [email protected]

Keywords: design and optimization of mechanical systems, industrial robot, robotization of welding, robot tool fastening.

ABSTRACT

In the robotized welding applications as a tool for robot is taken a torch. The working point of the tool, called Toll Centre Point (TCP) is generally established on the extension of the welding wire coming from the current nozzle. Fastening of the torch must ensure the invariability of the position of this point with respect to the last element of the robot manipulator, as well as the simplicity tool assembly/exchange with high repeatability. The fixing must be light and at the same time sufficiently rigid. It must ensure possibility to include the collision box, still used frequently.

Typical position of torch relative to the wrist of welding robot 1 - welding torch, 2 - fastening, 3 - collision box, 4 - robot wrist

The paper presents the problems that arise, when the torch is joined with other devices, for example sensor. It also discuss problems for the application of multi-torch welding on example of the of hybrid Plasma-MIG/MAG welding technology. I this case the tool is not the single torch, but integrated welding head, which includes two torches.

REFERENCES

[1] Szulc J., Pilat Z., Wojtczak Ł.: Robotization of hybrid welding. Plasma-MIG/MAG for components with a thickness over 20 mm. Pomiary Automatyka Robotyka PAR (ISSN 1427-9126), No 11/2014, 44-47 (in Polish). [2] Gawrysiuk W., Siennicki M.: Robotization of the hybrid welding process - application example. Przegląd Spawalnictwa - Welding Technology Review (ISSN 0033-2364), No 8/2011, 32-33 (in Polish). [3] I. Karabegović, B. Hrnjica I. Simulation of industrial robots for laser welding of load bearing construction, MECHANIKA (ISSN 1392 – 1207), 2009, No 2(76), 50,54. [4] PN-EN ISO 11593:2001 Manipulating industrial robots -- Automatic end effector exchange systems -- Vocabulary and presentation of characteristics.

MULTI – FREQUENCY PIEZOELECTRIC ENERGY HARVESTER BASED ON RHOMB TYPE CANTILEVER ARRAY

Andrius Čeponis 1, a *, Dalius Mažeika 2,b 1, 2 Vilnius Gediminas Technical University, Sauletekio avn. 11, 10223 Vilnius, Lithuania E-mail: a andrius,[email protected], b [email protected]

Keywords: piezoelectric energy harvesting, multi – frequency, cantilever beam array.

ABSTRACT

Paper focuses on numerical investigation of piezoelectric energy harvester which operates at multi – frequency mode. Employment of such operation principle extends frequency response spectrum and ensures higher efficiency at random excitation frequencies. Multi – frequency energy harvester has rhomb type shape with special design of seismic masses. Isometric view and principle scheme of the harvester are given in Fig.1. Therefore, it consist of eight cantilevers which are connected rigidly to each other and compose an indissoluble system. Seismic masses of the harvester has special design as well. Such design ensures additional lever arm and rotation moment at every corner of the harvester. Thereby, seismic masses have strong influence on strain distribution and it level as well as irregular design of cross section used in the harvester. Target of the proposed design is use first and second bending modes of sections and of whole system. Therefore, such design gives opportunity to generate close first and second bending modes of the cantilevers at a low excitation frequency spectrum and compounds of the cantilevers in a high excitation frequency spectrum. Such operation principle leads to wide frequency response spectrum. In order to perform numerical investigation, FEM (Finite Element Modeling) model was built by employing COMSOL 5.2 software. Modal analysis was fulfilled and it revealed that energy harvester has 11 different bending modes at range from 10 to 1000Hz. Numerical investigation of mechanical and electrical characteristics thru frequency response analysis confirmed results of the modal analysis and showed that harvester has 11 resonant frequencies at analyzed range. Moreover, maximum voltage and electrical energy obtained during numerical investigation reached 22.8V and 28μJ respectively.

Fig. 4 Design of the rhomb type cantilever array; a – Isometric view of the harvester; 1 –bolt for coupling host and harvester; 2 – clamping frame; 3 – bolts for coupling harvester and clamping frame; b – principle scheme of the harvester; 1 – clamping; 2 – 8 seismic masses; 9 – 16 piezoelectric ceramic; 17 – body of the harvester.

ANALYSIS OF INFLUENCE OF TYPE OF SOIL ON LONGITUDINAL MOTION OF LIGHTWEIGHT WHEELED MOBILE ROBOT – SIMULATION RESEARCH

Maciej Trojnackia, Przemysław Dąbekb* Industrial Research Institute for Automation and Measurements (PIAP) Poland, 02-486 Warsaw, Al. Jerozolimskie 202 E-mail: [email protected], [email protected]

ABSTRACT

Problem of influence of soil type on longitudinal motion of a lightweight four-wheeled mobile robot is considered. Kinematic structure, design, parameters of the robot and dynamics model of the wheel-ground system are described. Numerical analysis involving various velocities of robot motion and types of soil is performed. Motion parameters of the robot, ground reaction forces and moments, driving torques, wheel sinkage and longitudinal slip ratios of wheels are determined. Aggregated research results as well as detailed results of selected simulations are shown and discussed. Conclusions regarding influence of soil type on longitudinal motion of the robot are pointed out.

RESEARCH OF MODIFIED ATOMIC FORCE MICROSCOPE SENSOR USING IMPROVED 3D MODEL

Vytautas Bučinskas1,a, Andrius Dzedzickis1,b*, Artūras Ulčinas2,c , Inga Morkvėnaitė-Vilkončienė1,d, Sigitas Petkevičius1,e , Ryszard Jabłoński3,f 1 Faculty of Mechanical Engineering, Department of Mechatronics and Robotics, Vilnius Gediminas Technical University, J.Basanavičiaus str.28, LT-03224 Vilnius, Lithuania. 2 Department of Nanoengeenering, Institute of physics of center for physical sciences and technology, Savanorių str. 231, LT-02300 Vilnius, Lithuania. 3 Faculty of Mechatronics, Warsaw technical university, Bobola 8, 02-525 Warsaw, Poland. E-mail: [email protected], [email protected], [email protected]. dinga.morkvenaite- [email protected], [email protected], [email protected].

Keywords: atomic force microscope, finite element method, cantilever, aerodynamic force, nonlinear stiffness.

ABSTRACT

This paper is intended to present research and results of modification of atomic force microscope sensor. This paper represents part of continuous research, which is focused on increase of scanning speed in contact regime of atomic force microscope (AFM). Purpose of our research is to create method and equipment which will allow increase AFM scanning speed using original cantilevers. Main factor from which depends maximal scanning speed of AFM is cantilever resonance frequency. In case then cantilever excitation frequency created by roughness of scanned sample becomes similar to cantilever resonance frequency contact between probe and sample becomes unstable resulting in inaccurate scanning results [1]. Proposed AFM improvement method is based on the enhancement of dynamic characteristics of AFM sensor. Sensor dynamic characteristics are improved adding to the system additional controllable nonlinear force. This force acts on the cantilever surface and prevents possibility of contact loss between probe and sample surface. Additional force created using stream of various gases, directed to the flat surface of AFM cantilever. Dynamic model of AFM sensor with applied aerodynamic force were presented in [2-3] respectively. Purpose of this paper is to define characteristics of additional aerodynamic force using improved e 3D model of modified sensor as development of initial model. Aerodynamic research of interaction of gas stream to the cantilever body performed using SolidWorks flow simulation. Results of simulation brings us dependencies between pressure of applied compressed air and additional controlled stiffness in AFM sensor. Air duct diameter, shape and distance to cantilever surface influence to aerodynamic borne additional force to AFM sensor properties are defined. Obtained mentioned dependencies complements results presented in [3] and describes characteristics of additional aerodynamic force more precisely. Finally obtained results are presented in graphical form and corresponding conclusions are drawn.

REFERENCES [1] A. Dzedzickis, V. Bučinskas, N. Šešok, I.Iljin, E. Šutinys, Modelling of dynamic system of atomic force microscope. International conference Mechatronics ideas for industrial applications, Gdansk, Poland. (2015), 26. [2] A. Dzedzickis, V. Bučinskas, N. Šešok, I.Iljin, Modelling of mechanical structure, of atomic force microscope. 11th International Conference Mechatronic Systems and Materials, Kaunas Lithuania. (2015), 63-64. [3] V. Bučinskas, A. Dzedzickis, E. Šutinys, T. Lenkutis, Implementation of different gas influence for operation of modified atomic force microscope sensor. 12th international conference Mechatronic Systems and Materials, Bialystok, Poland. (2016), 99. 93

DIRECT MEASUREMENT OF SIX-PHASE INDUCTION DRIVE MAGNETIC FLUX IN THE AIR GAP

Donatas Uznysa*, Dominykas Beištarasb, Aurelijus Pitrėnasc Vilnius Gediminas Technical University, Department of Automation, Naugarduko g. 41, Vilnius LT–03227, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: frequency inverter, induction motor, multi-phase drive, magnetic flux.

ABSTRACT

This paper presents an overall description of the experimental rig of six-phase induction drive. The experimental rig was developed at Vilnius Gediminas technical university for educational and research purposes. Magnetic flux density measurements at maximum stator voltage and at 27% of maximum stator voltage are presented and discussed. Trajectory of magnetic flux density spatial vector is circular when six-phase drive is supplied with nominal stator voltage. When stator voltage is low the trajectory of magnetic flux density spatial vector becomes elliptical and the αβ components of magnetic flux density consist of high magnitude low frequency harmonics.

REFERENCES [1] S. J. Bugenis, J. Vanagas, S. Gečys, Optimal phase number of induction motor with the integrated frequency converter, Elektron. Elektrotech. 88(8) (2008) 67–70. [2] J. Bukšnaitis, Electromagnetical Efficiency of the six-phase winding, Elektron. Elektrotech. 3(119) (2012) 3–6. [3] J. Bukšnaitis, Research of electromagnetic parameters of single-layer three-phase and six-phase chain windings, Elektron. Elektrotech. 19(9) (2013) 11–14. [4] J. Bukšnaitis, Investigation and comparison of three-phase and six-phase cage motor energy parameters, Elektron. Elektrotech. 21(3) (2015) 16–20. [5] A. Pitrėnas, D. Uznys, D. Beištaras, Production of circular stator current trajectory in multi-phase induction drive under open phase fault condition, Balkan journal of electrical & computer engineering. 1(5) (2017) 1-4. [6] M. Duran, I. Gonzalez-Prieto, N. Rios, F. Berrero, A simple, fast and robust open-phase fault detection technique for six-phase induction motor drives, IEEE T. Power Electr. 99 (2017). [7] P. Cascaldi, A. Tilli, Parameter estimations of induction motor at standstill with magnetic flux monitoring, IEEE T. Contr. Syst. T. 3(13) (2005) 386-400. [8] A. Ceban, R. Pusca, R. Romary, Study of rotor faults in induction motors using external magnetic field analysis, IEEE T. Ind. Electron. 59 (2012) 2082-2093. [9] Z. Liu, G. Tian, W. Cao, X. Dai, B Shaw and R. Lambert, Non-invasive load monitoring of induction motor drives using magnetic flux sensors, IET Power Electron. 10 (2017) 189-195.

VEGETABLE HARVEST ASSESSMENT BY ANALYSIS OF VIBRATIONS

1, a 2,b 3,c Eugenijus Jurkonis , Rimantas Stonkus , Andrius Dzedzickis 1VGTU, Department of Printing Machines, Assotiated professor, Basanavicius 28, Vilnius, Lithuania 2VGTU Department of Printing Machines, Assotiated professor, Basanavicius 28, Vilnius, Lithuania 3VGTU Department of Mechatronics and Robotics, Assistant, Basanavicius 28, Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: Vibrations, Natural Frequencies, Finite Element Method, Vegetable harvest assessment.

ABSTRACT

Essential qualitative and quantitative harvest assessment is needed in order to plan and execute timely harvest when growing vining vegetables [1,2]. This is especially true in the harvesting by removing a few or several times during the fruiting season [3]. Usually, evaluation is carried out visually, and this takes time, but is not always successful because of lush foliage (especially in the cultivation of vegetables in the field) [4]. The paper proposes an assessment of harvest quantitative parameters using analysis of mechanical vibrations. Demonstration of the method is shown for the situation where support system in the field helps cucumbers grow vertically. Designed support construction digital model and calculated its natural vibrational frequencies by using FE method are proposed. In addition, analysis was done by modeling the foliage and / or cucumber yield. Most attention was paid to natural vibrational frequencies. The results were verified by laboratory experiment, actually simulating digital model. Measurements were done by taking advantage of the simple vibration recorders to capture oscillations of such a system as induced reaction to shock excitation. Counted and measured oscillation frequencies were recorded in the three test groups: - support model of cucumber vertically growing (numerical and experimental); - growing cucumber vertical support model and lush foliage; - cucumbers growing vertical support model, foliage and various harvest cases (corresponding to poor, medium and rich harvests). The method showed fairly significant changes in the lowest natural frequencies in different situations in the digital modeling and in experimental observation. Summarizing the results, it is possible to propose a use of such method for approximate harvest assessment and to manage best suitable times to collect cucumbers. The method can be adjusted using „machine learning" elements for more accurate interpretation of the values of lowest natural vibration frequency variations.

REFERENCES

[1] P. Butz, C. Hofmann, B. Tauscher, Recent developments in noninvasive techniques for fresh fruit and vegetable internal quality analysis, Journal of food science, 2005, 51-59. [2] Rafael R. Sola-Guirado, Francisco Jimenez-Jimenez, Gregorio L. Blanco-Roldan, Sergio Castro-Garcia, Francisco J. Castillo-Ruiz, Jesus A. Gil-Ribes, Vibration parameters assessment to develop a continuous lateral canopy shaker for mechanical harvesting of traditional olive trees, Spanish Journal of Agricultural Research, 2016, Vol 14, No 2. [3] S. Castro-Garcia, G.L. Blanco-Roldán, L. Ferguson, E.J. Gonzalez-Sanchez, J.A. Gil-Ribes, Frequency response of late-season 'Valencia' orange to selective harvesting by vibration for juice industry, -Biosystems Engineering, 2017, Vol. 155, 77-83. [4] Da Silva, F. C., Da Silva F. M., de Carvalho Alves M., e Silva Ferraz G. A., Sales R.S. Efficiency of coffee mechanical and selective harvesting in different vibration during harvest time. Coffee Science, 2015, Vol. 10.1: 56-64.

DEVELOPMENT OF MULTIFUNCTION ELECTRIC ARC COATINGS OBTAINED BY SPRAYING OF CORED WIRES ON THE BASE OF FECRB- AL AND FE-CR-C-AL

Mykhajlo Student1, Justinas Gargasas2, Irmantas Gedzevičius2, Hanna Pokhmurska3, Oleksandra Student1, Lyudmyla Dzyubyk3, Volodymyr Gvozdeckii1 1Karpenko Physico Mechanical Institute of the National Academy of Saiencies of Ukraine, Lviv, Ukraine, 2Vilnius Gediminas technical university, Vilnius 3National University "Lviv Polytechnic", Ukraine E-mail: [email protected], [email protected]

Keywords: electric arc sprayed coatings, cored wires, structural and phase state of coating, functional properties (adhesion, cohesion, hardness, microhadness, residual stress, wear resistance beyond boundary friction, abrasive and gasoabrasive wear at higher temperature), basic principles of composition cored wires.

ABSTRACT Spraying of a special electrode - powder cored wires (PCW) - the electric arc coatings with operational characteristics at the level of the best plasma coatings can be obtained. The choice of PCW composition is based on the obtained experimental dependences between the cohesive-adhesion characteristics of coatings, the level of residual stresses in them and their structural-phase state. To determine the phase state of coatings from PCW a known structural diagram for continuous materials was modified taking into account the microheterogeneity (MH) of the coatings, the amount of alloying elements dissolved in the solid solution and in an oxide phase. It was shown that structure of the coatings (their microstructure, phase composition, and MH) is determined by the completeness of the fusion components for filling of the PCW cores and its shells. It was proposed to evaluate the MH of the coatings using the entered KMH ratio. It characterize the deviation of the components content in individual lamellas of coatings from their average content in the coating in general. Generally the KMH ratio of coatings lowers as the powder particle size of the PCW decreases. However, an opposite tendency was revealed for the aluminum and magnesium particles. This is explained by the blocking of PCW components fusion because of the refractory Al2O3 and MgO oxide films on their surface. The choice criterion of the optimal composition of PCW charge for renovation coatings is to ensure the formation the minimum amount of oxide phase in the coating by alloying of a ferritic matrix with sufficient amount of aluminum and carbon. To ensure high workability of coatings under abrasive wear the PCW charge composition should provide a high hardness and low residual stresses of the coating. The stress level should be lower, leading to the appearance of a cracks grid on the surface of the coating during its grinding. The criterion of the optimal composition of PCW charge for spraying of renovation coatings for operation under boundary friction is to form the coatings with three-phase structure consisting of martensite, austenite and ferrite. The necessary workability of coatings during service at elevated temperatures in the conditions of gas-abrasive wear is achieved by forming a two-layer coating. Its inner layer provides the adhesion of the spraying coating to the substrate, and the outer one ensures the wear resistance of the coating. An austenite-martensitic structure is formed in the inner coating layer due to the high MH of aluminum content. The tensile stresses in this layer are transformed into compressive ones in the temperature range of operation 500...700 оС because of the residual austenite to martensite transformation. In addition the coating MH creates the favorable conditions for diffusion welding of the coating with the substrate and lamellas together. The conditions for dispersion hardening are created in the outer coating layer sprayed by the PCW of the system Fe-Cr-B with the addition of

aluminum, magnesium, nickel and tungsten. The structure of the coatings is formed from disperse phases due to possible of the diffusion processes at operating temperatures (500…700ОС). In coatings of Fe– Cr–B–Al system additionally are formed Fe2B borides and Fe3Al type intermetallic particles. These nanodispersed particles provide high wear resistance to the spraying coating. Adding of Ni to previous PCW composition leads to formation of Ni3Al phase in the coating structure and to the improving of hardening effect. Adding of W to core wire’s mixture causes formation of Fe7W6 intermetallics particles in structure of coatings, which provides the maximum effect of disperse hardening (coating’s hardness increases more than 15 percent). These PCW compositions have been introduced into the technological process of protecting and renovation of the different elements automobiles, printing, agricultural and heat power plants equipments etc.

BUSHING SHAFT ASSEMBLY WEAR CALCULATION PRINCIPLES

Karlis Berzins1,a*, Janis Rudzitis1,b Institute of Mechanical Engineering, Riga Technical university, Viskalu street 36A, Riga, LV - 1006, Latvia E-mail: [email protected], [email protected]

Keywords: Bushing wear, wear calculation principles, veneer transportation, bushing shaft assembly.

ABSTRACT

Wear existed it exists now and it will be present in the future. To calculate wear means to prevent unplanned machinery breakdown by predicting the necessary moment for special wear off part like bushing replacement. Current studies[1] are designed for surfaces with constant nominal contact area for example piston and cylinder. Bushing shaft assembly differs from piston/cylinder example because the nominal contact area changes depending of wear. The bigger wear the larger nominal contact area. Schematic drawing of bushing and shaft assembly can be seen in figure 1, where 푥, 푦, 푧 are ordinate axles, 푂푣, 푂 centre points, 푅 is bushing inner radius, 푟 is shaft radius, 푢 is wear, 퐿 is contact arc length and 푙 is bushings length.

Figure 1: Bushing shaft assembly schematic

Nominal contact area which is determined by part geometrical dimensions 푙휋푟 푅2 − (∆ + 푢)2 − 푟2 퐴 = ∗ 2 ∗ 푎푟푐푐표푠 ( ) 푎 180 2(∆ + 푢)푟 Is calculated based on circle-circle intersection [2] where ∆ is clearance fit. Starting nominal contact area 푙 ∗ 휋 ∗ 푟 푏 퐴 = arccosin ( ) 푎푠 180 푟 calculations are based on Hertz contact stresses[3], where 푏 is arc length projections half. Wear calculation are based on experimental theoretical principles. Experimental theoretical method is based on fatigue theory where two surface asperities moving against each other create tension field and after few cycles break. Wear is calculated with formula [1] 2 푞 3 푆푎 퐸{푈푛} ≈ 푘푒−푚 ∗ 푘푟 ∗ 푘푓−푚 ∗ ( ) ∗ 푎 ∗ 푣푡, 퐸 푆푚2 where 푘푒−푚 is surface anisotropy and fatigue parameter coefficient, 푘푟 is surface roughness parameter complex, 푘푓−푚 is physical and mechanical parameter complex, q is load (includes previously 98

푎 mentioned nominal contact area), E is Young’s modulus, 푆푎, 푆푚2 are surface roughness parameters, 푣 is velocity and 푡 is duration. This method is experimental theoretical because currently run-in process cannot be calculated and some parameters should be measured after run-in process. Methodology is carried out in sequence[1]:  Starting data determination: Kinematic properties (푞,푣,퐿푏,푡) Material physical properties (푚, 휎0, 푁0) Material mechanical properties (퐸, 휇))  Parameter determination after run-in: 푎 Surface roughness parameters (푆푎,푅푠푚1, 푅푆푚2 푆푚2 ); Run-in wear (푈푝) and its duration (푇푝)

REFERENCES

[1] G. Springis, J. Rudzitis, A. Avisane, and A. Leitans, “Wear calculation for sliding friction pairs,” Latv. J. Phys. Tech. Sci., pp. 41–54, 2014. [2] E. W. Weisstein, “Circle-Circle Intersection.,”From MathWorld A Wolfram Web. [Online]. Available: http://mathworld.wolfram.com/Circle-CircleIntersection.html. [3] R. G. Budynas and J. K. Nisbett, Shigley’s Mechanical Engineering Design, 10th ed. 2015.

THE CRACK SURFACE TOPOGRAPHY OF STRUCTURAL MATERIALS

Wojciech Macek1, a *, Tomasz Wołczański1, b, Krystyna Rajczyk2, c, Zbigniew Marciniak3, d, Grzegorz Garbacz4, e 1 Opole University of Technology, Faculty of Production Engineering and Logistics, Department of Engineering and Work Safety, 31 Sosnkowskiego Street, 45-272 Opole, Poland 2 Institute of Ceramics and Building Materials, Building Materials Engineering Division in Opole, 21 Oświęcimska Street, 45-641 Opole, Poland 3 Opole University of Technology, Faculty of Mechanical Engineering, Department of Mechanics and Machine Design, 5 Mikołajczyka Street, 45-271 Opole, Poland 4 Opole University of Technology, Faculty of Production Engineering and Logistics, Department of Knowledge Engineering, 75 Ozimska Street, 45-370 Opole, Poland E-mail: a [email protected], b [email protected], c [email protected], d [email protected], e [email protected] * the corresponding author

Keywords: surface metrology; focus variation method; fatigue of materials; steel; fly ash binder; composite materials.

ABSTRACT This paper shows experimental investigations of the topography of the surface which was carried out using the focus variation microscope Alicona Infinite Focus, an optical 3D measurement device, which allows the acquisition of data sets with large depth of focus. Selected results of measured crack surfaces for such materials as steel, fly ash binder and composite, was analyzed according to e.g. surface texture standards ISO 25178 and ASME B46.1. Fracture surface topography is one of the basic macroscopic investigations aimed at determining the cause of the damage [1]. It allows to determine what kind of the loading (static or fatigue) material was subjected. Several of typical macroscopic patterns of fatigue damage can be distinguished, as functions of type and magnitude od loading. The surface analysis reveal localization of initiation and crack path propagation as well as identifying the areas for further microscopic analysis. The fracture surfaces analysis was made on steel specimens subjected to fatigue random loading bending and combination bending with torsion loadings [2, 3]. The analysis was performed using the focus variation microscope Alicona Infinite Focus, an optical 3D measurement device, which allows the acquisition of data sets with large depth of focus. The measurement device was equipped with a motorized nosepiece using a set of five dedicated microscopic objective lenses 2.5×; 5×; 10×; 20×; 50×; and 100× magnification. In fatigue fracture cases, for bending and torsion loadings [4, 5], authors studied total area with magnification 10x. Crack initiation and rupture area was scaned with magnification 100x, as shown in figure 1.

100

c) Fig. 1. Steel S355 specimen subjected to combined bending-torsion loading a) with marked crack initiation and rupture areas, b) Crack initiation area with parameters of roughness profile, c) rupture area with parameters of roughness profile Specimens of fly ash binder [6] (fig. 2) and composite materials (fig.3) were also analyzed.

a) b)

c) Fig. 2. Fly ash binder specimen a) isometric view, b) front view with line of profile maesurment, c) 3d view with detail of crack 101

Fig. 3. The element of composite specimen for tensile testing

REFERENCES

[1] R.I. Stephens, A. Fatemi, R.R. Stephens, H.O. Fuchs, Metal fatigue in engineering, John Wiley and Sons, Inc. (2001). [2] Z. Marciniak, D. Rozumek, E. Macha, Fatigue lives of 18G2A and 10HNAP steels under variable amplitude and random non-proportional bending with torsion loading, Int. J. of Fatigue, 30(5) (2008) 800- 813, doi.org/10.1016/j.ijfatigue.2007.07.001. [3] Z. Marciniak, D. Rozumek, E. Macha, Verification of fatigue critical plane position according to variance and damage accumulation methods under multiaxial loading, Int. J. of Fatigue, 58 (2014) 84-93, doi.org/10.1016/j.ijfatigue.2013.02.021. [4] W. Macek, E. Macha, The Control System Based on FPGA Technology For Fatigue Test Stand MZGS- 100 PL, Arch. Mech. Eng., 62(1) (2015) 85-100, doi:10.1515/meceng-2015-0006. [5] W. Macek, E. Macha, Energy-Saving Mechatronic System for Fatigue Tests of Materials under Variable- Amplitude Proportional Bending and Torsion, Solid State Phenomena, 164 (2010) 67-72, doi:10.4028/www.scientific.net/SSP.164.67. [6] K. Rajczyk, Popioły lotne z kotłów fluidalnych i możliwości ich uszlachetniania, Monografia, Wydawnictwo Instytut Śląski Sp. z o.o., Opole 2012 [in Polish].

102

STUDIES ON THE EFFECTS OF THE GAS COMPOSITION DURING DEPOSITION OF DLC-FILMS BY PACVD

Gerda Vaitkūnaitė1, Daniel Heim2, Christian Forsich3, Irmantas Gedzevicius4, Justinas Gargasas5 1,4,5 Vilniaus Gediminas Technical University 2,3 University of Applied Sciences Upper Austria E-mail: [email protected];[email protected]; [email protected]; [email protected]

Keywords: Diamond-Like coatings, DLC, Plasma assisted chemical vapor deposition, tribology, adhesion, hardness, wear resistance, coefficient of friction.

ABSTRACT

Scope of the work was to analyze how different gas compositions – acetylene (C2H2), acetylene and nitrogen (C2H2+N2), acetylene and hydrogen (C2H2+H2) influence on Diamond-Like coatings (DLC) properties during plasma assisted chemical vapor deposition process (PACVD) with MICROPULS® system and integrated HMDSO silicone precursor. These comparisons where made with three different process temperatures - 400°C, 500°C, 575°C on two substrates: 1.7225 (ISO 10083- 1:2006) and 1.3343 (ISO 4957:2003 ). Spherical-abrasive, tribological, wear, local contact damage and Vickers microhardness (HV microindenation) tests were carried out. Afterwards, analysis with contact Confocal Scanning Laser Microscopy (CLSM) and optical microscopy were performed. The characterization of the film was made in regards of tribology, adhesion, hardness and wear resistance. The results showed, that coatings sprayed in higher temperature conditions were able to build more sp3 carbon structure, which resulted in improved tribological and adhesive properties.

103

THE POWER OF ARTIFICIAL INTELLIGENCE IN MEDICAL IMAGE ANALYSIS

Prof. Aliaa Youssif Faculty of computers and information, Helwan University, Cairo, Egypt

ABSTRACT

Nowadays, artificial intelligence (AI) has a great potential in our life. It encompasses almost everything in our civilized life starting from mobile’s app to self-driving cars, to gaming, to medical diagnosis, to even autonomous weapons. Recent researches in AI focus on the development and analysis of algorithms to create plenty of new software that will be running those huge AI applications. Medical image processing can be considered recently as one the most attractive research areas due to the considerable achievements that significantly improved the type of medical care available to patients. It’s a multidisciplinary that requires comprehensive knowledge in many areas such as medicine, pattern recognition, artificial intelligence, and image processing. This presentation outlines the power of artificial intelligence current trends in medical image analysis. This can highly assist physicians in diagnosing, treating, and monitoring changes of various diseases. Applying Artificial intelligence in medical image analysis offers humans a power chance at better healthcare, with more efficiency and precision.

104

IMPEDANCE CONTROL METHOD FOR EXPERIMENTAL SIMULATION OF TRAFFIC VIBRATIONS IN MONOLITHIC BRIDGE WIDENING

Pui-Lam Ng1,2 a *, Albert Kwok-Hung Kwan2,b 1Faculty of Civil Engineering, Vilnius Gediminas Technical University, Sauletekio Al.11, Vilnius LT-102223, Lithuania 2Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China E-mail: [email protected], [email protected] *corresponding author

Keywords: Bridge widening, concrete stitch, impedance control, traffic vibration.

ABSTRACT

In monolithic bridge widening, a new deck is constructed alongside the existing deck and a concrete stitch is cast to connect both decks. Due to practical reasons it is often required to maintain traffic flow during casting of the concrete stitch [1,2]. As a result, the curing concrete stitch would be subjected to traffic vibration, whose amplitude decreases as the concrete stitch gains strength [3,4]. There had been a lack of proper control algorithm to simulate such loading condition, and thus widely different results of vibration resistance of concrete stitches had been reported [4,5]. To address this gap, an impedance control method for experimental simulation of traffic vibrations has been developed by the authors. At any vibration cycle during testing, the load applied by the hydraulic actuator to the concrete stitch specimen is automatically determined from the force and displacement feedback signals in the previous vibration cycles. The actuation system is real-time computer controlled by a bespoke impedance-dependent control programme. With the use of this new test method, a series of concrete stitch specimens have been tested by subjecting to different vibration amplitudes for establishing reliably traffic vibration limits in bridge widening projects.

REFERENCES [1] D.G. Manning, Effects of Traffic-Induced Vibrations on Bridge-Deck Repairs, National Cooperative Highway Research Program Synthesis of Highway Practice 86, Transportation Research Board, National Academy of Sciences, Washington DC, USA, 1981, 40pp. [2] H.L. Furr, F.H. Fouad, Effect of moving traffic on fresh concrete during bridge-deck widening, Transportation Research Record No. 860 (1982) 28-36. [3] P.L. Ng, A.K.H. Kwan, Structural failure of concrete stitch in bridge widening and its mitigation, in: C.M. Wang, K. Murugappan (Eds.), Proceedings of International Conference on Structural and Foundation Failures, Singapore, 2004, pp. 113-122. [4] P.L. Ng, J.S. Du, X.R. Hui, G. Kaklauskas, Evaluation of traffic vibration mitigation measures for curing concrete stitch in bridge widening project, in: C.K. Choi (Ed.), Proceedings of the 2011 World Congress on Advances in Structural Engineering and Mechanics, Seoul, Korea, 2011, pp. 1573-1590. [5] J.S. Du, P.L. Ng, F.T.K. Au, Highway bridge widening: Structural considerations and research needs, in: J.J. Gao, J. Lee, J. Ni, L. Ma, J. Mathew (Eds.), Proceedings of the 3rd World Congress on Engineering Asset Management and Intelligent Maintenance Systems, Beijing, China, 2008, Springer-Verlag, pp. 436-441.

105

QUANTITATIVE ASSESSMENT OF DANCE THERAPY INFLUENCE ON UPPER LIMB BIOMECHANICS FOR A PEOPLE WITH PARKINSON’S DISEASE

Donatas Lukšys1, a *, Dalius Jatužis2, b, Rūta Kaladytė – Lokominienė3, c, Ramunė Bunevičiūtė4, d, Gabrielė Mickutė5, e, Alvydas Juocevičius6, f, Julius Griškevičius7, g 1, 7 Department of Biomechanics, Vilnius Gediminas Technical University, Vilnius, Lithuania 2, 3, 4 Clinics of Neurology and Neurosurgery, Vilnius University Faculty of Medicine, Vilnius University Santaros Klinikos Hospital, Vilnius, Lithuania 5, 6 Centre of rehabilitation, physical and sports medicine, Vilnius University Santaros Klinikos Hospital, Vilnius, Lithuania E-mail: a [email protected], b [email protected], c [email protected], d [email protected], [email protected], f [email protected], [email protected]

Keywords: inertial sensor, upper limb, Parkinson disease, dance therapy, the unified Parkinson’s disease rating scale (UPDRS)

ABSTRACT

Parkinson's disease is one of the neurodegenerative disorders that affect peoples’ voluntary movements, and can be described by the motor symptoms. The most common PD motor symptoms are bradykinesia (slowness of movement), rigidity (stiffness in the limbs), tremor and shuffling gait [1]. Meanwhile PD almost for all patients is diagnosed in later stages of the disease, and the diagnosis is based on clinical symptoms. For PD diagnosis and evaluation of the severity Unified Parkinson’s disease rating scale (UPDRS) is used. For a quantitative assessment of the movements various motion capture techniques can be used. These techniques ranges from video cameras for measuring the gross motion of human body to application for tremor detection using single accelerometers [2]. During the last decade Inertial Measurement Unit (IMU) became popular. IMU allows capturing the human movements and compare with the data of an image capture cameras. Researchers for detection of bradykinesia used IMU mounted on the wrist [3], others used two IMU, which were attached to the subject's upper arm and forearm [4]. Various physical rehabilitation programs are used to reduce certain motor symptoms for the patients with PD. Lately, more often for PD therapy are applied various dance therapy, such as Argentinean tango [5]. Experimental data from 20 participles was obtained in cooperation with the Vilnius University Hospital Santaros Klinikos neurology and rehabilitation, physical and sport centres. Total 20 subjects diagnosed with Parkinson’s disease were recruited for the study and were divided into two groups: PD and CO groups. During the motor tasks focused on the performance of upper limbs, the kinematics of the movement were recorded using wireless IMU sensors (Shimmer Research, Dublin, Ireland). In this study, we selected the elbow joint flexion – extension movement in the sagittal plane and for the quantitative assessment of the upper limb of 12 kinematic parameters were calculated. MATLAB software was used to process the raw measurement data and calculate the above mentioned metrics.

106

REFERENCES [1] J. S. Perlmutter. Assessment of Parkinson Disease Manifestations. Curr Protoc Neurosci. 2009 Oct [2] A. Yu Meigal, S.M. Rissanen, M.P. Tarvainen, S.D. Georgiadis, P. A Karjalainen, O. Airaksinenand, M. Kankaanpää. Linear and nonlinear tremor acceleration characteristics in patients with Parkinson's disease. Physiol Meas. Mar. 33 3 2012 395-412 [3] A. Salarian, H. Russmann, C. Wider, P.R. Burkhard, F.J. Vingerhoets, K. Aminian. Quantification of Tremor and Bradykinesia in Parkinson’s disease Using a Novel Ambulatory Monitoring System. IEEE Trans Biomed Eng. Feb; 54 2 2007 313 – 22. [4] T.Q. Mentzel, R.Lieverse, A.Levens, C.L. Mentzel, D.E. Tenback, P.R. Bakker, H.A.M. Daanen, P.N. van Harten. Reliability and validity of an instrument for the assessment of bradykinesia. Psychiatry Research. Volume 238 2016 189 – 195. [5] D. Lötzke, T. Ostermann, A. Büssing. Argentine tango in Parkinson disease – a systematic review and meta- analysis. BMC Neurol. Nov 5 2015 15:226

107

METHODS FOR MEASURING THE FRICTION COEFFICIENT OF THE ROAD SURFACE

Elena Perova1, a, Evgeniya Ugnenko1, b, Olga Gubareva1, c, Gintas Viselga2, d* 1Kharkiv National Automobile and Highway University, Department of Researches and Designing of Highways and Airports, Ukraine 2Vilnius Gediminas Technical University, Department of Mechanical and Materials Engineering, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected]

Keywords: coefficient of friction, runway, aerodrome, method for measuring the friction coefficient, measuring wheel, decelerometer, aircraft, surface roughness, microprofile.

ABSTRACT

The most popular methods of determining the coefficient of friction are analyzed in this article. Their advantages and disadvantages are given. A comparison of instruments for measuring the frictional properties of airfields is shown. The methods of determining the coefficient of friction of the road surface are considered. Implementation of these methods makes it possible to determine the coefficient of friction at any speed, which allows measuring the coefficient of friction on the runway, on the aircraft parking place, when taxiing, in hangars, on the highways in use at any time (observing all the traffic rules), while maintaining or commissioning new highways, in all turns and a small extension of the coating surface.

108

INVESTIGATION OF PARTICLES COAGULATION WITH TWO METHODS INFLUENCING THE ACOUSTIC FIELD

Audrius Čereška1,a*, Irina Grinbergienė2,b 1, 2 Vilnius Gediminas Technical University, Department of mechanical Engineering, Basanavičiaus str. 28, LT- 03224, Vilnius, Lithuania E-mail:[email protected], [email protected]

Keywords: acoustic field, frequency of sound, particles, coagulation.

ABSTRACT

Reduction of the dispersion of various pollutants is the basic problem addressed in environment protection. Metal processing industry, solid fuel burning and diesel engine emissions account for the bulk of the ejections into the atmosphere. Due to their extremely small sizes the particles can travel long distances through the atmosphere. Collection of pollution particles measuring less than 10 µm in diameter by conventional cleaning devices (cyclones, scrubbers, etc.) is a complex task. Purification of air from extremely small particles requires the application of complex, multi-step air cleaning systems. New methods facilitating effective reduction of solid particle pollution are sought for perpetually. This article describes our investigation into the reduction of environment pollution with solid particles (aerosol) by means of coagulation. For our experimental research special stands of two structures containing measuring equipment were used. The principles of operation of the experimental stands and the methodologies of running the experiments are provided. Experimental investigation into the effectiveness of coagulation of small-diameter solid particles depending on the acoustic field impact angle was performed. For exciting the acoustic field one or two acoustic generators were used depending on the stand structure. With two acoustic generators switched on the particle impact angle was changed. The findings show the dependence of particle coagulation on the frequency, amplitude and impact angle of acoustic signal. Comparison and analysis of research findings is provided.

REFERENCES

[1] Z. Yun., Z. Xinwu, G. Changchao, Experimental research on acoustic agglomeration of fine aerosol particles in the standing – wave tube with abrupt section, J. Acoust. Soc. (2014) 2375. [2] J. Liu, G. Zhang, J. Zhou, J. Wang, W. Zhao, K. Cen, Experimental study of acoustic agglomeration of coal – fired fly ash particles at low frequencies. Powd. Techn. 193 (2009) 20-25. [3] D. Markauskas, R. Kačianauskas, A. Maknickas, Numerical particle – based analysis of the effects responsible for acoustic particle agglomeration, Adv. Powd. Techn. 26 (2014) 698-704. [4] A. Shalunov, V. Khmeliov, K. Shalunova, Acoustic Coagulation of Aerosol, Lambert Academic Publishing (2012) [5] V. Vekteris, V. Strishka, D. Ozarovskis., V. Mokshin, Experimental investigation of processes in acoustic cyclone separator, Adv. Powd. Techn. 25 (2014) 1118-1123. [6] N.N. Chernov, Hydrodynamic interaction of an ensemble of weighted particles in a sound field, Materials of the Third All – Russian Scientific Conference with International Participation, Taganrog, News of TRTU 5 (2004) 115-117 (in Russian). [7] E.P. Mednikov, Acoustic Coagulation and Precipitation of Aerosols. Consultant, New-York, 1963. [8] L. Song, G. H. Koopmann, T. L. Hoffmann, An improved theoretical model of acoustic agglomeration, J. Vibr. Acoust. 116 (1994) 208-214. [9] T.L. Hoffmann, Environmental implication of acoustic aerosol agglomeration, Ultrasonic 38 (2000) 353- 357. [10] O.A. Ezekoye, Y.W. Wibowo, Simulation of acoustic agglomeration processes using a sectional algorithm, J. Aero. Sci. 30 (1999) 1117-1138. 109

[11] T.L. Hoffman, An extended kernel for acoustic agglomeration simulation based on the acoustic wake effect, J. Aero. Sci. 28 (2006) 919-936. [12] Ch. Sheng, X .Shen, Modelling of acoustic agglomeration processes using the direct simulation Monte Carlo method, J. Aero. Sci. 37 (2006) 16-36. [13] S. Dong, B. Lipkens, T.M.M. Cameron, The effects of orthokinetic collision, acoustic wake, and gravity on acoustic agglomeration of polydisperse aerosols, J. Aero. Sci. 37 (2006) 540-553. [14] A.E. Kabeel, M. Elkelawy, H. Bastawissi, A.M. Elbanna, A. M. 2016. Solid particles injection in gas turbulent channel flow, En. Pow. Eng. 8 (2006) 367 – 388. [15] A.R. Noorpoor, A. Sadighzadeh, H. Habibnajed, Experimental Study on Diesel Exhaust Particles Agglomeration using Acoustic Waves, Int. J. Auto. Eng. 2 (2012) 252-260. [16] Y. Wang, J. Hu, Ultrasonic removal of coarse and fine droplets in air, Sep. Purif. Techn. 153 (2016) 156- 161. [17] J. Yan, L. Chen, L. Yang, Combined effect of acoustic agglomeration and vapor condensation on fine particles removal, Chem. Eng. J. 290 (2016) 319-327 [18] D. Zhou, Z. Luo, M. Fang, M. Lu, J. Jiang, H. Chen, M. He, Numerical calculation of particle movement in sound wave fields and experimental verification through high-speed photography, Appl. Ener. 185 (2016) 2245 -2250. [19] D. Markauskas, R. Kacianauskas, A. Maknickas, Numerical particle-based analysis of the effects responsible for acoustic particle agglomeration. Adv. Powd. Techn. 26 (2014) 698-704. [20] D. Sun, X. Zhang, L. Fang, Coupling effect of gas jet and acoustic wave on inhalable particles agglomeration, J. Aero. Sci. 66 (2013) 12-23. [21] H. Chen, H.Z. Luo, J. Jiang, D. Zhou, M. Lu, M. Fang, K. Cen, Effects of simultaneous acoustic and electric fields on removal of fine particles emitted from coal combustion, Powd. Techn. 281 (2015) 12-19. [22] C. Sheng, X. Shen, Modelling of acoustic agglomeration processes using the direct simulation Mote Carlo method, J. Aero. Sci. 37 (2006) 16–36. [23] E. Riera, I. Gonzalez-Gomez, G. Rodrigue, J.A. Gallego-Juarez, Ultrasonic agglomeration and preconditioning of aerosol particles and other applications, Powd. Ultrason. 38 (2015)1023–58. [24] Q. Guo, Q. Z. Yang, J. Zhang, Influence of a combined external field on the agglomeration of inhalable particles from a coal combustion plant, Powd. Techn. 227 (2012) 67-73. [25] D. Pui, Sh. Chen, Z. Zuo, PM2,5 in China: Measurments, sources, visibility and health effects, and mitigation. Particuology 13 (2014) 1-26.

110

ANALYSIS OF VIBRATION EFFECTS ON THE COMFORT OF LOW FLOOR BUS USERS BY OSCILLATORY MODEL

Artūras Kilikevičius1, a *, Antanas Fursenko2, b, Kristina Kilikevičienė3, c, Nikolaj Šešok 4, d, Igor Iljin 4, e 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania 2 Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 3 Department of Automobile Transport, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 4 Department of Printing Machines, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected] , [email protected], [email protected] * corresponding author

Keywords: low floor bus, vibration, dynamic characteristics.

ABSTRACT

The paper analyzes the effects of vibrations on the comfort of low floor bus users. Evaluation of vibration effects was carried out according to the criteria set out in the 1997 ISO 2631-1 standard for comfort in public means of transport. Comfort is determined for the space of a driver, passenger in the middle part of the bus and passenger in the rear overhang. Also, the allowable exposure time to vibrations in drivers for the reduced comfort criterion was determined according to the 1978 ISO 2631-1 standard. The bus spatial oscillatory model was developed for the needs of the analysis. Simulation was performed using the MATLAB software.

REFERENCES [1] O.O. Okunribido, S.J. Shimbles, M. Magnusson, M. Pope, City bus driving and low back pain: a study of the exposures to posture demands, manual materials handling and whole-body vibration, Appl. Ergon. 38 (1) (2007) 29–38. [2] Azad, N. L.; Khajepour, A.; McPhee, J. 2007. Effects of locking differentials on the snaking behaviour of articulated steer vehicles, Int. J. Vehicle Systems Modelling and Testing, 2 (2): 101–127. [3] Alperovitch-Najenson, Y. Santo, Y. Masharawi, M. Katz-Leurer, D. Ushvaev, L. Kalichman, Low back pain among professional bus drivers: ergonomic and occupational-psychosocial risk factors, IMAJ 12 (2010) 26–31. [4] Bodin, D.; Merbouh, M.; Balay, J. M.; Breysse, D.; Moriceau, L. 2009. Experimental study of the waveform shape effect on asphalt mixes fatigue, In: Proceeding of the 7th international RILEM symposium on advanced testing and characterization of bituminous materials, (ATCBM09), 2: 725–734. [5] Chen, J. P.; Chen, W. W.; Zhu, H.; Zhu, M. F. 2010. Modelling and simulation on stochastic road surface irregularity based on Matlab/Simulink, Transactions of the Chinese Society of Agricultural Machinery, vol. 41, no. 3, p. 11–15. [6] Davis, L.; Bunker, J. 2011. Altering heavy vehicle air suspension dynamic forces by modifying air lines, Int. J. Heavy Vehicle Systems, vol. 18, no. 1, p. 1–17, Jan. 2011.

111

EXPERIMENTAL RESEARCH OF LOW FLOOR BUS

Keywords: low floor bus, vibration, dynamic characteristics.

ABSTRACT

The article describes the dynamics researches of low floor bus. The goal of research is to determine the stability of mechanical system of low floor bus. The article accomplishes experimental research of an urban bus: the oscillatory measurements of significant points of the bus structure and the experimental modal analysis of the body have been performed.

REFERENCES [1] Alem, N. 2005. Application of the new ISO 2631-5 to health hazard assessment of repeated shocks in U.S, Army vehicles, Industrial Health. 43:403–412. [2] Azad, N. L.; Khajepour, A.; McPhee, J. 2007. Effects of locking differentials on the snaking behaviour of articulated steer vehicles, Int. J. Vehicle Systems Modelling and Testing, 2 (2): 101–127. [3] Balsarotti, S.; Bradley, W. 2000.Experimental evaluation of a non-intrusive automotive suspension testing apparatus, in: SAE 2000 World Congress, no. 2000-01-1329. [4] Bodin, D.; Merbouh, M.; Balay, J. M.; Breysse, D.; Moriceau, L. 2009. Experimental study of the waveform shape effect on asphalt mixes fatigue, In: Proceeding of the 7th international RILEM symposium on advanced testing and characterization of bituminous materials, (ATCBM09), 2: 725–734. [5] Chen, J. P.; Chen, W. W.; Zhu, H.; Zhu, M. F. 2010. Modelling and simulation on stochastic road surface irregularity based on Matlab/Simulink, Transactions of the Chinese Society of Agricultural Machinery, vol. 41, no. 3, p. 11–15. [6] Davis, L.; Bunker, J. 2011. Altering heavy vehicle air suspension dynamic forces by modifying air lines, Int. J. Heavy Vehicle Systems, vol. 18, no. 1, p. 1–17, Jan. 2011.

112

RESEARCH OF WASTEWATER TREATMENT WITH USED TIRES SHREDS

Ina Tetsman1, a *, Kristina Baziene2,b , Justinas Gargasas3,c, Gintas Viselga4,d 1,2,3,4 Basanavicius str. 28, Vilnius , Lithuania E-mail: a [email protected], b [email protected], c [email protected], d [email protected]

Keywords: cleaning, secondary raw materials, tyres shreds.

ABSTRACT

One of the biggest wastewater pollutants are petroleum products. The petroleum products are very dangerous pollutants in the environment. There are a lot of different ways of treating waste water from oil products. There are a lot of research done with different origin and structure sorbents are being used for effluent treatment. Producing adsorbents from secondary raw materials (used tires) is reducing the amount of waste and also protecting nature of dangerous materials. During cleaning of waste water the main side oil components are being absorbed. The processes are based on adsorption method, in which a liquid phase of a substance is accumulated on particulate material surface. The study evaluated three different sizes of tyres particles. (0.63–1.00mm; 1.00–1.5 mm and 1.5–3.00 mm). The fractions of 1.00– 1.5 mm and 1.5–3.00 mm have shown the better cleaning effectiveness. The effectiveness was 94,6 % of wastewater cleaning with used tired shreds.

REFERENCES [1] Baltrenas, P.; Vaišis, V. 2007. Naftos produktų sorbentai aplinkosaugoje. Vilnius: Technika. 162 pp. [2] Bao, M.; Wang, L.; Sun, P.; Cao, L.; Zou, J.; Li, Y. 2012. Biodegradation of Crude Oil Using an Efficient Mi-crobial Consortium in a Simulated Marine Environment. Marine Pollution Bulletin. 349–359. [3] Barkauskas, V. J. 2007. Naftos perdirbimo technologija 1. Kaunas: Technologija. 78 pp. [4] Heavy metal adsorbents for storm water pollution prevention. Eduction and training the national shipbuild- ing research program. California: San Diego, 1997, 20 pp. [5] Staniskis, J. 2005. Integrated Waste Management: Concept and Implementation. 33(3): 40–46. [6] Stone, R. W.; Fenske, M. R.; White, G. C. 1994. Bacteria Attacking Petroleum and Oil Fractions, 169– 178. [7] Severin Е.S., Aleinikova Т.L., Osipov Е.V. 2000. Biologicheskaya ochistka. Woskow: High School, 210 pp.

113

EXPERIMENTAL RESEARCH OF GRAVIMETRIC SYSTEM

Artūras Kilikevičius1, a *, Antanas Fursenko2, b, Kristina Kilikevičienė3, c, Romuald Obuchovski 1, d, 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania 2 Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 3 Department of Geodesy and Cadastre, Vilnius Gediminas Technical University, Saulėtekio al. 11, LT-10223 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected], * corresponding author

Keywords: gravimeter, gyroscope, gravimetric system.

ABSTRACT

The gravimeter is an instrument used for measurements of local variations in Earth’s gravitational field. The constant downward gravitational acceleration varies by about 0.5% on the surface of the Earth, due to the planet internal structure, land masses, metallic ores deposits, surface shape etc. In this paper, a description of the design and operation principle of the dynamically gravimeter is given. This design allows for the gravimeter signal separation from the noise, which makes it possible to increase the measurement accuracy of Earth’s gravitational field.

REFERENCES [1] Huang Y., et al., “SGA-WZ: A New Strapdown Airborne Gravimeter”, Sensors, vol. 12, no.7, 2012, 9336- 9348. DOI: 10.3390/s120709336. [2] Zhai Z., et al., The accuracy evaluation and analysis of airborne gravimetry in coastal area, Cehui Xuebao/Acta Geodaetica et Cartographica Sinica, vol. 44, issue 1, 2015, 1–5. [3] Bezvesilna О., “Autocompensation of the gyroscopic gravimeter measurement errors”. In: Proceedings of the International Scientific Conference Mechanics 2004, Rzeszow University of Technology, Poland, 2004, 21–28. [4] Bezvesilnaya, E., Tkachuk, А., and Kozko, K. (2013) Gravimeter Output Filtering, XV International PhD Workshop OWD 2013, (33), pp. 306-309. [5] Bezvesilnaya, E., Tkachuk, А. and Kozko, K. (2013) System for airborne gravimetry, European Applied Sciences, 5(2), pp. 37-39.

114

INVESTIGATION OF ROLLER INTERACTIONS WITH STEEL TAPE

Artūras Kilikevičius1, a *, Antanas Fursenko2, b, Kristina Kilikevičienė3, c, Sergejus Borodinas 1, d 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania 2 Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 3 Department of Automobile Transport, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected], [email protected] * corresponding author

Keywords: steel tape; tape transport, roller interactions.

ABSTRACT

In commercial tape drives, a tape is transported between the supply and take-up packs at a fixed axial tension and transport speed and over edge and surface guides. The tape decks must assure accurate guiding and transport of the tape while it accelerates and decelerates by holding the axial tension constant. During transport, lateral in-plane vibration of tape’s narrow edge causes misalignment between tape and roller. This article is motivated by the need to conduct a detailed investigation into the frictional interaction between roller surface and tape.

REFERENCES [1] Richards DB, Sharrock MP. Key issues in the design of magnetic tapes for linear systems of high track density. IEEE Trans Magn 1998; 34(4). [2] Taylor R, Talke F. High frequency lateral tape motion and the dynamics of tape edge contact. J Micromech Inf Precision Equip 2003. [3] Richter W, Talke F. Nonrepeatable radial and axial runout of 5 disk drive spindles. IEEE Trans Magn 1988;24(6). [4] Ono K. Lateral motion of an axially moving string on a cylindrical guide surface. J Appl Mech 1979;46:905–12. [5] Ono K. Transversal motion transfer characteristics of axially moving tape over guide post with coulomb friction. Jpn J Tribol 1997;42(5). [6] Eaton J. Behavior of a tape path with imperfect components. Adv Inf Storage Syst 1998;8. [7] Taylor R, Strahle P, Stahl J, Talke F. Measurement of cross-track motion of magnetic tapes. J Inf Storage Process Syst 2000;2(4).

115

EXPERIMENTAL INVESTIGATION OF FRICTION TRANSITION ON LATERAL VIBRATION OF STEEL TAPES

ABSTRACT

Lateral tape displacement and roller axial runout are measured on an experimental tape transport. The effect of roller axial runout on lateral displacement of tape is investigated. Tape lateral displacement is found to be generated at the roller surface, and is observed to be correlated to roller axial runout. A number of typical roller types are investigated to determine the mechanism causing lateral tape displacement. Edge contact and friction are each shown to play a role in the creation of lateral tape displacement in the tape path.

REFERENCES [1] V. Kartik, J.A. Wickert, Vibration and guiding of moving media with edge weave imperfections, Journal of Sound and Vibration 291 (2006) 419–436 [2] V. Kartik, J.A. Wickert, Surface friction guiding for reduced high frequency lateral vibration of moving media, ASME Journal of Vibration and Acoustics 129 (2007) 371-379 [3] M.R. Brake, J.A. Wickert, Frictional vibration transmissions from a laterally moving surface to a traveling beam, Journal of Sound and Vibration 310 (2008) 663-675 [4] Ryan J. Taylor, Frank E. Talke, Investigation of roller interactions with flexible tape medium, Tribology International 38 (2005) 599-605 [5] Bart Raeymaekers, Frank E. Talke, Lateral Motion of an axially moving tape on a cylindrical guide surface, Journal of Applied Mechanics 74 (2007) 1053-1056 [6] Mark Denny, Stick-slip motion: an important example of self-excited oscillation, European Journal of Physics 25 (2005) 311-322

116

INFLUENCE OF HEAT TREATMENT ON MICROSTRUCTURAL EVOLUTION AND MECHANICAL CHARACTERISTICS OF THE AL-6061 ALLOY

Hanae Chabba1, a *, Irmantas Gedzevičius2, b, Justinas Gargasas2, c, Driss Dafir1, d 1sciences & techniques faculty, P. O. Box 2427 Imouzzer road Fez, 30000, Morocco. 2 VGTU Faculty of Mechanical Engineering, J. Basanavičiaus g. 28, Vilnius, Lithuania E-mail: a [email protected], b [email protected], c [email protected] d [email protected]

Keywords: Aluminum alloy 6061-T6, heat treatment, mechanical properties, microstructural characterization.

ABSTRACT

Mechanical properties of a material depend mainly on their chemical composition, parameters of precipitation process, and heat treatment. Aluminum alloys have attracted attention of many researchers, engineers and designers and had been used in different fields like industry, aeronautics, automobile sector. Especially, Aluminum-Magnesium-Silicon (Al-Mg-Si) series, denoted as 6xxx series, containing magnesium and silicon as its major alloying elements, and it’s one of many commercial aluminum alloys that can be significantly hardened by heat treatment. The aim of the work presented is to evaluate the influence of heat treatment on the mechanical properties and microstructural evolution in Al-6061-T6 alloys containing additives of Copper. Heat treatment is the most important controlling factors used to enhance the mechanical properties of aluminum alloys. Heat treatment process can be classified into two processes, including homogenization and quenching. The microstructural evolution of an Al-6061 alloy with an excess of copper was examined using Scanning Electron Microscopy SEM, X-ray diffraction and measuring the mechanical properties of this alloy, as hardness, micro-hardness and tensile, during heat treatment for two different temperature of homogenization and quenching.

REFERENCES

[1] Sharma, s.c., girish, b., kamath, r., and sathish, b.m., fractography, fluidity and tensile properties of aluminium/hematile particle composite, J. Mater Eng. performance, (1999), 8(3): 309-314. [2] Mondolfo L. F., Aluminum Alloys Structures and Properties, Butterworth, London, 12, p. 1-3, (1976). [3] Seah k.h.w., sharma, s.c., and krishna, m., damping behavior of al 6061/albite mmcs, J. ASTM Int., (2006), 3(3) paper id 5a1 12394 [4] Murtha sj. new 6xxx aluminum alloy for automotive body sheet applications sae, Int. J. mater Manuf, (1995);104:657–66. [5] Buha j, lumley rn, crosky ag. microstructural development and mechanical properties of interrupted aged Al–Mg–Si–Cu alloy. J. Metall. Mater Transa (2006);37a:3119–30. [6] Ozturk f., sisman a., toros s., kilic s., et picu r.c., influence of aging treatment on mechanical properties of 6061 aluminum alloy, J. Mat. and Design, 2010, 31, 972-975. [7] Randolph Kissell J. Robert L. Ferry, Aluminum structures a guide to their specifications and design second edition, John wiley & sons, New York, (1996), 18.

117

INVESTIGATION OF DYNAMIC IMPACT OF FIREARM WITH SUPPRESSOR

Keywords: firearm suppressor; dynamic, ballistics, firearm ergonomic.

ABSTRACT

The internal ballistics processes occur in the tube during firearm firing. They cause tremendous vibratory shock forces and robust sounds. The determination of these dynamic parameters is relevant in order to reasonably estimate the firearm ergonomic and noise reduction features. The objective of this study is to improve the reliability of the results of measuring a firearm suppressor’s dynamic parameters.

REFERENCES [1] Borzino AMCR, Apolinario, JA, de Campos, MLR. Estimating direction of arrival of long-range gunshot signals. Telecommunications Symposium (ITS), 2014 International. 17-20 August 2014, Sao Paulo. p.1-5. [2] Branch M. P. Comparison of suppression and ear-level hearing protection in firearm use. Otolaryngology Head Neck Surgery. 2011. Vol. 144 (6): 950-953. [3] Wilson K, Head J, Helton WS. Friendly fire in a simulated firearms task. Proceedings of the Human Factors and Ergonomics Society Annual Meeting. September 2013. Vol. 57. No. 1: 1244-1248 [4] Kilikevicienė K, Skeivalas J, Kilikevicius, A, Peceliūnas R; Bureika G. The analysis of bus air spring condition influence upon the vibration signals at bus frame // Maintenance and reliability = Eksploatacja i niezawodność. Warsaw : Polish Maintenance Society. ISSN 1507-2711. Vol. 17, iss. 3 (2015), p. 463-469. [5] Zheng X, Soons J, Vorburger TV, Song J, Renegar T, Thompson R. Applications of surface metrology in firearm identification. Surface Topography: Metrology and Properties. 2014. 2 (1):1-10.

118

MIXED MODE I/II FRACTURE UNDER DYNAMIC LOADING FRACTURE

Algis Pakalnis*,Petras Šadreika**, Antanas Žiliukas*** * SE Road and Transport Research institute, I. Kanto Street 25, Kaunas 2082, Lithuania, E-mail: [email protected] ** Kaunas University of Technology, Kęstučio 27, 44025 Kaunas, Lithuania, E-mail: [email protected] *** Kaunas University of Technology, Kęstučio 27, 44025 Kaunas, Lithuania, E-mail: [email protected]

Keywords: pure mode fracture, mixed mode fracture, dynamic impact testing

ABSTRACT In this investigation, a finite element modeling approach is used to investigate stabile crack propagation under opening mode (I-mode) and in-plane-shear mode (II-mode) and mixed I/II-mode loading conditions. Finite element modeling study consists of three-point bending beam pre-cracked specimens with initial crack orientation angles 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45° with applied force. The specimens were made from various construction steel S235, 11SMn30, 11SMnPb30 and C45. Specific attention is given to force-displacement curves. Finite element modeling was implemented with Johnson-Cook material model and Johnson-Cook fracture model.

REFERENCES

[1] G. C. Sih. 1974. Strain-energy-density factor applied to mixed mode crack problems. International Journal of Fracture; 10(3): 305-321. [2] M. R. Ayatollahi, M. R. M. Aliha, H. Saghafi. 2011. An improved semi-circular bend specimen for investigating mixed mode brittle fracture. Engineering Fracture Mechanics 78:110-123. [3] M. R. Ayatollahi, A. R. Torabi. 2009. A criterion for brittle fracture in U-notched components under mixed mode loading. Engineering Fracture Mechanics 76:1883-1896. [4] D. Rittel, A. Pineau, J. Clisson, L. Rota. 2002. On testing of Charpy specimens using the one-point bend impact technique. Experimental Mechanics 42(3): 247-252. [5] L. Toth, H. P. Rossmanith, T. A. Siewert. 2002. Historical background and development of the Charpy test. European Structural Integrity Society 30: 3-19. [6] R. O. Ritchie, J. F. Knott, J. R. Rice. 1973. On the relationship between critical tensile stress and fracture toughness in mild steel. Journal of the Mechanics and Physics of Solids 21: 395-410. [7] M. Gintalas, K. Kalnins, A. Pakalniš, P. Šadreika, A. Žiliukas. 2015. Evaluation of static and dynamic stress intensity factors under pure mode I and mixed mode I/II fracture. Solid State Phenomena 220-221: 667-672. [8] A. Žiliukas. 2008. Irimo Mechanika. Kaunas, Technologija 184 p.

119

EXPERIMENTAL ANALYSIS OF NOISE AND VIBRATION OF A DIESEL ENGINE

Artūras Kilikevičius1, a *, Antanas Fursenko2, b, Kristina Kilikevičienė3, c, Darius Vainorius1, d, Jonas Matijošius3, e, Alfredas Rimkus3, f, Akos Bereczky 4, g 1 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania 2 Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 3 Department of Automobile Transport, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 4 Department of Energy Engineering, Budapest University of Technology and Economics, Milegyetem rkp. 3-9, H-1111 Budapest, Hungary E-mail: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected] * corresponding author

Keywords: biodiesel; compression ignition engine, engine vibration, sound pressure level.

ABSTRACT

REFERENCES [1] Atalay M, Anafarta N, Sarvan F. The relationship between innovation and firm performance: an empirical evidence from Turkish automotive supplier industry. Proc - Soc Behav Sci 2013;75:226-35. [2] Holm M, Garcia AC, Adamson G, Wang L. Adaptive decision support for shop- floor operators in automotive industry. Proc CIRP 2014;17:440-5. [3] Ganapathy T, Gakkhar RP, Murugesan K. Influence of injection timing on performance, combustion and emission characteristics of Jatropha biodiesel engine. Appl Energy 2011;88:4376-86. [4] Ong HC, Mahlia TMI, Masjuki HH, Honnery D. Life cycle cost and sensitivity analysis of palm biodiesel production. Fuel 2012;98:131-9. [5] Alptekin E, Canakci M, Ozsezen AN, Turkcan A, Sanli H. Using waste animal fat based biodiesels- bioethanol-diesel fuel blends in a DI diesel engine. Fuel 2015;157:245-54. [6] Arbab MI, Masjuki HH, Varman M, Kalam MA, Imtenan S, Sajjad H. Fuel properties, engine performance and emission characteristic of common biodiesels as a renewable and sustainable source of fuel. Renew Sustain Energy Rev 2013;22:133-47. [7] Zhang H, Zhou Q, Chang F, Pan H, Liu X-F, Li H, et al. Production and fuel properties of biodiesel from Firmiana platanifolia L.f. as a potential non-food oil source. Ind Crops Prod 2015;76:768-71.

120

DETERMINING SNOW CAPACITY OF SNOW PROTECTION FACILITIES ON ROADS IN THE MOUNTAINOUS AREA

Оlga Тymchenko1, a, Gintas Viselga2, b* 1Kharkiv National Automobile and Highway University, Department of Researches and Designing of Highways and Airports, Ukraine 2Vilnius Gediminas Technical University, Department of Mechanical and Materials Engineering, Lithuania E-mail: [email protected], [email protected]

Keywords: snow capacity, snow-retaining capacity, snow protection facility, snow sediment, road in the mountainous area.

ABSTRACT

The article deals with the snow capacity of snow protection facilities. The purpose of the given work is to determine the snow capacity of snow protection facilities on roads in the mountainous area. To carry out theoretical studies there were applied analytical methods. The article presents a general form of formulas for determining the snow-retaining capacity and the snow capacity of snow protection facilities through well-known geometrical parameters and there were offered protective means against snowdrift. We will adopt the following protective measures against snowdrift: placement of walls and other structures to prevent blowing of snow from the surrounding areas into basins that prevents the accumulation of snow on the slopes and in ravines; afforestation of snow retention pools, placing ditches, walls, retaining walls along the movement of snow to prevent its replacement; snow mass removal by guide walls sideward away from the structure to be protected.

121

STATISTICAL ANALYSIS OF COMPRESSION IGNITION ENGINE PARAMETERS FUELLED WITH VARIOUS BIODIESELS

Keywords: biodiesel; compression ignition engine, engine vibration, sound pressure level

ABSTRACT

Noise and vibration of ignition compression engine is one of the most complicated field to cope with since every mechanism that compose of the engine affect them separately. In this study, effect of various biodiesel on engine noise and vibration has been studied on an unmodified compression ignition engine. The results revealed that noise and vibration of the engine decreased with increasing biodiesel ratio until pure biodiesel usage and in linear regression analysis.

REFERENCES [1] Gopal K Nantha, Karupparaj R Thundil. Effect of pongamia biodiesel on emission and combustion characteristics of di compression ignition engine. Ain Shams EngJ 2015;6:297-305. [2] Mohsin R, Majid ZA, Shihnan AH, Nasri NS, Sharer Z. Effect of biodiesel blends on engine performance and exhaust emission for diesel dual fuel engine. Energy Convers Manage 2014;88:821-8. [3] Cheung CS, Man XJ, Fong KW, Tsang OK. Effect of waste cooking oil biodiesel on the emissions of a diesel engine. Energy Proc 2015;66:93-6. [4] Habibullah M, Masjuki HH, Kalam MA, Rizwanul Fattah IM, Ashraful AM, Mobarak HM. Biodiesel production and performance evaluation of coconut, palm and their combined blend with diesel in a single- cylinder diesel engine. Energy Convers Manage 2014;87:250-7. [5] Tuccar G, Tosun E, Ozgur T, Aydm K. Diesel engine emissions and performance from blends of citrus sinensis biodiesel and diesel fuel. Fuel 2014;132:7-11. [6] Ozener O, Yuksek L, Ergeng AT, Ozkan M. Effects of soybean biodiesel on a DI diesel engine performance, emission and combustion characteristics. Fuel 2014;115:875-83. [7] Sayin C, Gumus M, Canakci M. Influence of injector hole number on the performance and emissions of a DI diesel engine fueled with biodiesel-diesel fuel blends. Appl Therm Eng 2013;61:121-8.

122

PROVIDING A GIVEN POSITION MULTIPLE SUPPORTED STRUCTURES STRUCTURES BEAM

Lyudmyla Dzyubyk1, Hanna Pokhmurska2, Andriy Dzyubyk3 1,2,3 National University "Lviv Polytechnic", Ukraine E-mail: [email protected]

Keywords: optimal design, beam structures, supports regulation, supports elastic deformation optimization axis of rotation.

ABSTRACT

Extended structures placed on separate supports are widely used in industry: above-ground pipeline; welded bridge elements; rotating-type cement kilns machine, drying drums etc. Deflection of linear structures from a given vertical position leads to excess stresses and strains. The result may cause local destruction in the form of cracks, especially in areas of stress concentration process. Typical causes of pillars displacement are elastic deformation with significant operational loads or locations in areas with unstable soil or in mountainous areas. It is therefore necessary to make additional adjustment of the poles in a production environment. It is important to know the value displacement of supports taking into account possible external influences.

Analysis of existing sources: It is now widely used computational methods based on the theory of elasticity and using computer modeling. In the last case, the most characteristic, finite element method, which provides visibility of results and the possibility of accounting features geometry. However, in the case of multiple supported structures is difficult to perform a unified modeling and computation. More applicable in this case is to present designs as a continuous beam model. The most studied case are hard supported beams with stable and variable cross-section. Separately studied the characteristics of strength beam on elastic supports. However, the strength of the beam by vertical displacement im case of supports elastic deformation not been studied sufficiently. Therefore, relevant and important to study the model of static balance variable stiffness beam on elastic supports with known displacement. We consider piecewise constant beam bending stiffness, which is free on NR resilient supports under concentrated and distributed piecewise constant stress. The method of Cauchy functions for constructing general solutions of differential equations. These equations have variable coefficients for solving equations beam deflection. The system of equations describing this structure: Next, using the ratio between full, elastic and adjusting can determine the displacements of the last. The algorithm for calculating, adjusting movements: 1) Measure the initial full movement supports 0 0 wi , i  1, NR . Solving the system of equations we find reactions R i , i  1, NR ; 2) Use new needed 1 0 movement of supports wi , i  1, NR . Solving the system again of equations we find new reactions R i 1 0 1 0 zi  wi  wi  i (Ri  Ri ) , i  1, NR ; 3) Calculate the desired adjustment by formula . Adjusted beam algorithm implemented in the environment Delphi. To test the accuracy of problem results, use known in the literature example of calculation casing cement kiln, which is set on eight pillars. Found that the case accepted values compliances observed displacement of shell is in the range of 2 to 6 mm. Conclusions. On the basis of problem solving of static balance beam a continuous piecewise constant bending stiffness placed on resilient supports with the possibility of adjusting movements obtained system of linear algebraic equations to determine the reactions of the supports beams. The calculation of rotating unit on eight supports of continuous action were done and necessary movement of to ensure the straightness of the axis of rotation were found.

123

SOME FEATURES OF THE RHEOLOGICAL PROPERTIES OF COMPOSITE MATERIALS WITH FUNCTIONALIZED CARBON NANOADDITIVES

Zhanna S. Shashok1,a, Konstantin V. Vishnevskii1,b, Nikolay R. Prokopchuk1, c 1Belarusian State University of Technology, Sverdlov st., 13 a, 220006, Minsk, Republic of Belarus E-mail: [email protected], [email protected], [email protected]

Keywords: rubber, nanoadditives, nanotubes, nanofiber, functional groups, service characteristics, cyclic deformation, heat resistance.

ABSTRACT

Question of the hour related to the use of highly disperse carbon additives in rubber compounds are the problem of their homogeneous distribution, as well as the determination of the mechanism of the modifying effect of these components. The use of carbon nanomaterials makes it possible to influence both the rheological and performance characteristics of elastomeric compositions [1-3]. Filled elastomeric compositions based on special-purpose rubbers BNKS-18 and combinations of BNKS-18 + BNKS-28 (in the ratio of 50:50) were used as research objects. The compositions differ in the proportion of ingredients of the vulcanizing system and fillers, besides they contain different mark of carbon black. The influence of three type of nanomaterials: non-specialized and functionalized with amino- and oxygen-containing groups was investigated in the work. In order to determine the effect of highly dispersed carbon additives on the properties of elastomeric compositions, the basic rheological characteristics of rubber compounds were determined. Based on data on the definition of the Payne effect, it has been determinate that the introduction of highly dispersed carbon additives into rubber mixtures based on butadiene-nitrile rubbers increases the uniformity of the distribution of carbon black in the volume of the elastomeric matrix. The improvement of the macro- and microatomization parameters of fillers in rubber mixtures with the nanoadditives may be due to the increase in the interaction at the rubber-carbon black border through the transformation of the network structure of the filler and the improvement of wetting of the filler surface by the polymer. It should be noted that the functionalization of the surface of the carbon nanomaterial does not always have a positive effect on the dispersion of carbon black. The use of highly disperse carbon additives in the composition of elastomeric compositions leads to a decrease in the Mooney viscosity of rubber compounds. Which, may be, caused by both the decrease in the number of defects in the volume of the elastomeric composition due to better dispersion of the filler, and the decrease in the elastic deformation of the filler network structure with highly dispersed additives. In this case, a decrease in the initial viscosity and Mooney viscosity of rubber compounds will help reduce energy costs in the production of rubber products.

REFERENCES

[1] Likozar Blaž, Major Zoltan Morphology, mechanical, cross-linking, thermal, and tribological properties of nitrile and hydrogenated nitrile rubber/multi-walled carbon nanotubes composites prepared by melt compounding: the effect of acrylonitrile content and hydrogenation // Appl. Surf. Sci. 2010. Vol. 257, No 2. – Pp. 565–573. [2] Vishnevskii K.V., Shashok Zh.S., Prokopchuk N.R., Krauklis A.V., Zhdanok S.A. Improvement of the service properties of elastomer compositions by introduction of carbon nanomaterials Journal of engineering physic and thermophysics. 2012. Vol. 85, No 5. – Pp. 1086–1091. [3] Wang T., Alan B. Dalton, Joseph L. Keddie Importance of molecular friction in a soft polymer−nanotube nanocomposite // Macromolecules. 2008. No 41 (20). Рp. 7656–7661.

124

DINAMICAL RESEARCH OF PHOTOVOLTIC SYSTEM

Vytautas Makarskas1, a, Mindaugas Jurevičius2, b, Artūras Kilikevičius3, c 1 Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 2 Department of Mechanical Engineering, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT- 03224 Vilnius, Lithuania 3 Institute of Mechanical science, Vilnius Gediminas Technical University, J. Basanavičiaus str. 28, LT-03224 Vilnius, Lithuania E-mail: [email protected], [email protected], [email protected]

Keywords: photovoltaic module, degradation, mechanical stress, climatic stress simulation, failure.

ABSTRACT

Efficiency of modern photovoltaic (PV) systems decreases significantly when the crystalline structure of PV modules is damaged due to climatic factors, such as wind and mechanically similar dynamic effects. Nowadays PV modules are used in different dynamic objects like cars, boats etc., where dominant loads are of dynamic environment. This paper presents theoretic and experimental studies. For the investigation of dynamic loads acting on PV modules, a testing stand has been designed. PV modules were loaded with cyclic dynamic loads. During the experiment, the PV modules were loaded with external excitation, the excitation amplitude is not exceeding more than 7 mm. During the experiment, the PV modules were excited, in the frequency range of 0 to 40 Hz and the sweep generating mode was used. The aim of this excitation to simulate different weather conditions. Experimental and theoretical results showed the reaction of PV modules in different weather conditions (which means that the effect of different wind speeds is evaluated). The proposed assessment methodology can be applied successfully when designing PV modules and accounting for mechanical dynamic effects.

REFERENCES

[1] D. Reiche, M. Bechberger., Policy differences in the promotion of renewable energies in the EUmember states, Energ Policy 32 (7) (2004) 843–849, http://dx.doi.org/10.1016/S0301-4215(02)00343-9. [2] G. Li, R. Zhu, Y. Yang, Polymer solar cells, Nat. Photonics 6 (2012) 153–161, http://dx.doi.org/10.1038/nphoton.2012.11. [3] B. Parida, S. Iniyan, R. Goic, A review of solar photovoltaic technologies, Renew. Sust. Energ. Rev. 15 (3) (2011) 1625–1636, http://dx.doi.org/10.1016/j.rser.2010.11.032. [4] A. Hinsch, H. Brandt, W. Veurman, S. Hemming, M. Nittel, U. Würfel, P. Putyra, C. Lang-Koetz, M. Stabe, S. Beucker, K. Fichter, Dye solar modules for façade applications: recent results from project ColorSol, Sol. Energy Mater. Sol. Cells 93 (6–7) (2009) 820–824, http://dx.doi.org/10.1016/j.solmat.2008.09.049. [5] S. Yoon, S. Tak, J. Kim, Y. Jun, K. Kang, J. Park, Application of transparent dye-sensitized solar cells to building integrated photovoltaic systems, Build. Environ. 46 (10) (2011) 1899–1904, http://dx.doi.org/10.1016/j.buildenv.2011.03.010. [6] D. Chemisana, Building integrated concentrating photovoltaics: a review, Renew. Sust. Energ. Rev. 15 (1) (2011) 603–611, http://dx.doi.org/10.1016/j.rser.2010.07.017. [7] R. Singh, R. Banerjee, Estimation of rooftop solar photovoltaic potential of a city, Sol. Energy 115 (2015) 589–602, http://dx.doi.org/10.1016/j.solener.2015.03.016. [8] L.R. Ren, J. Qiu, S.Wang, Photovoltaic properties of graphene nanodisk-integrated polymer composites, Compos. Part B 55 (2013) 548–557, http://dx.doi.org/10.1016/j.compositesb.2013.07.017. [9] R. Haselhuhn, C. Hemmerle, U. Hartmann, et al., Leitfaden Photovoltaische Anlagen, 3. Auflage DGS – Deutsche Gesellschaft für Sonnenenergie e.V, Berlin, 2008.

125