Fundamentals of Design Topic 9 Structural Connections & Interfaces
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The Tinkerer's Pendulum for Machine System's Education
Session 2566 The Tinkerer’s Pendulum for Machine System’s Education: Creating a Basic Hands-On Environment with Mechanical “Breadboards” John J. Wood*, Kristin L. Wood** *Department of Mechanical Engineering, Colorado State University **Department of Mechanical Engineering, The University of Texas at Austin Abstract The pendulum of engineering education is swinging from an emphasis of theoretical material to a balance between theory and hands-on activities. This transformation is motivated, in part, by the changing students entering engineering programs. Instead of a tinkering background with the dissection of machines and use of tools, students are now entering with computer, video games, and other “virtual” experiences. This focus has left a void in the ability to relate engineering principles to real-world devices and applications. In this paper, we introduce a new approach for filling this void in a mechanical engineering curriculum. In particular, we describe modifications and extensions to machine design courses to include hands-on exercises. Through the application of “mechanical breadboards,” clear relationships between machine design principles and the reality of machine components are established. These relationships reduce the number of topics covered in the courses, but greatly increase the interest of the students and their potential retention of the material. 1. OVERTURE: INTRODUCTION 1.1 Motivation: Engineering education is transforming from a theoretical emphasis to a balance between applied mathematics and science material and hands-on activities. Design components in courses are helping to provide this balance. Instead of relegating design courses to the last two semesters of an engineering program, many universities are spreading the experiences across the entire 4-5 year curriculum. -
[email protected]
BOLTING Basics, Tips & Best Practices g... urin Feat SmartBolts® Direct Tension Indicating Fasteners™ Address: 202 Perry Parkway, Suite 7 Gaithersburg, MD 20877 United States Phone: +1 (240) 631-7246 Fax: +1 (240) 750-6025 Email: [email protected] URL: www.smartbolts.com www.stressindicators.com Stress Indicators Incorporated is a solutions-driven engineering and manufacturing firm based in Maryland, USA. Formed in 1992, we provide innovative Visual Indication Systems™ solutions for customers worldwide. Stress Indicators Incorporated invented and developed SmartBolts® technology and commercialized the products to enable broad industry acceptance. All SmartBolts® are manufactured from quality fasteners at our USA facility. Disclaimer While we try to make sure that all data/information posted in this report is accurate at all times, we are not responsible for typographical and other errors that may appear. Data/Information is subject to change without notice. Stress Indicators assumes no responsibility or liability for any damages incurred directly or indirectly as a result of any data errors, omissions, or discrepancies. BOLTING Basics, Tips & Best Practices Table of Contents Introduction ................................................................................................................................................. 4 Part One: Basics of Specifying a Bolt Step One: Specifying the Basics of a Fastener .......................................................................................... 6 Selecting a Head Type ............................................................................................................................. -
Design of Eccentric Load Carrying Lead Screw Mechanism: an Application of Auxiliary Rolling Shutter System Ajay N
International Journal of Management, Technology And Engineering ISSN NO : 2249-7455 Design of Eccentric Load Carrying Lead Screw Mechanism: An Application of Auxiliary Rolling Shutter System Ajay N. Patil1, Abhinav B. Patil2, Sumesh S. Narkhede3, Pandurang D. Mane4. 1-4Students, Mechanical Engineering Department, Dr. D. Y. Patil School of Engineering, Pune, (India) Abstract Now days, we see rolling shutters near about in every Shop, Garage, Workshops, etc. Some of them are Automatic, some are opened by Mechanical arrangements, & most of this are manually opened. Small scale industries & shops owners can’t afford the automatic shutters because of the high installation cost. Manual operation requires more manpower & more time. In this project we are going to design the auxiliary system for the opening of shutters. We providing more typeof openings in one system. In this system the shutter can be open by using mechanical arrangement, by using switches, & by using the remote control, & manual opening is also provided. This mechanism consists Lead screw, Bearing, Lead screw nut and assembly, Lead screw driving mechanism, Motor, Supporting structure, Lead screw selection. Lead screw for this application is placed on side due to this lead screw contains eccentric load. So in this research paper we design and analyse the lead screw against eccentric load. Keywords: Automatic Shutter, Auxiliary System, Eccentric Load, Lead Screw, Rolling Shutter. Nomenclature A = Cross-sectional area (mm2) dc = Core diameter e = Eccentricity = 400 mm = Factor of safety I = moment of inertia of the cross-section about the neutral axis (mm4) l = lead M= Applied bending moment (N-mm) =Torque required to raise the load (N-mm) W = Load required to raise the shutter= 34.11 Kg 335N p = pitch P = effort required to raise the load. -
Chain & Pulley Tensioners
CHAIN & PULLEY TENSIONERS Engineering Data Tensioner Arms idler Sprocket Sets Idler Roller Pulley Sets ENGINEERING DATA TENSIONING TECHNOLOGY Chain & V-Belt Tensioning Roller chains are power transmission components with positive transmission which, by virtue of their design are subject, depending on quality, to elongation as a result of wear of 1 to 3% of their total length. Inspite of this elongation, due to aging, a roller chain transmits the occurring torques effectively providing it is periodically retensioned. Without tension adjustment, the slack side of the chain becomes steadiliy longer, ascillates and reduces the force transmitting wrap angle of the chain on the sprockets. The chain no longer runs smoothly off the teeth of the sprockets, producing uneven running of the entire drive and supporting wear. The service life of the chain drive can be extended considerably by the use of an automatic chain tension adjuster. The tensioning element prevents the slack side of the chain from 'sagging' or 'slapping' by its automatic operation and very wide tensioning range for compensating this given elongation. The DUNLOP tensioning element is based on the rubber spring principle. According to application it is supplemented with the appropriate idler sprocket for chain drives or with a belt roller pulley in belt tensioner applications. Pretensioning With the tensioning element the necessary travel and simultaneously the corresponding initial tension force can be accurately adjusted by a torsion angle scale and indicating arrow. Excessive initial pretensioning of the chain should be avoided in order to reduce the tensile force and surface pressure on the links. Vibration Damping The DUNLOP tensioning element, based on a system of rubber springs, absorbs considerably the chain vibration due to internal molecular friction in the rubber inserts. -
Threaded Fasteners
Threaded Fasteners Introduction If you are designing and building a Formula SAE vehicle, threaded fasteners will likely be used to join the various components and systems together and allow the vehicle to function as a unified machine. The reliability of your vehicle is key to realize your potential at the competition. Even though threaded fasteners have been in use for hundreds of years and are in products that we use every day, their performance is dependent on a wide range of factors. This chapter covers some of the main factors that can influence reliability and is intended as an aid in joint design, fastener selection, and installation. The first portion of this chapter covers several design and installation factors that can work together to improve the reliability of your vehicle’s bolted joints. These topics include, the importance of generating and maintaining clamp load, and how clamp load, along with joint stiffness, can work together to prevent self-loosening and improve fatigue performance. The second portion of this chapter reviews how installation method and torque are related to clamp load, and also includes a comparison between common fastener types to aid in selection. The chapter concludes with a short tutorial showing how to obtain Mil Spec information on fasteners and similar hardware. Disclaimer – Multiple factors on each component in a bolted joint affect its performance. Additionally, service requirements for every joint differ. Each joint must be evaluated and tested for its ability to perform the desired function. The information in this chapter provides general background and does not represent how a specific design or piece of hardware will perform. -
Design and Analysis of Chain Drive Power Transmission from Stationary to Oscillating Devices
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 03 | Mar 2019 www.irjet.net p-ISSN: 2395-0072 DESIGN AND ANALYSIS OF CHAIN DRIVE POWER TRANSMISSION FROM STATIONARY TO OSCILLATING DEVICES P. Ramesh1, T. Abinesh2, R. Aravind Babu2, P.R. Jagadeesh Babu2 1Asst Professor, R.M.K. Engineering College, Chennai, Tamil Nadu, India 2UG Student, R.M.K. Engineering College, Chennai, Tamil Nadu, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - A conventional transmission system consists of situations, the second gear is placed and the power is the driver and driven in same axis. If driver axis is changed to recovered by attaching the shafts or hubs to this gear. Though 15° the axis of driven also must be changed to 15° or else drive chains are often being a simple oval loops, they can also failure of the machine element will take place. This work be going around the corners by placing more than two gears modifies the chain so which the driver can be placed along the chain; gears that does not gives power into the stationary and driven can be oscillated by -45° to +45°. Here, system or transmit it out are generally known as the idler- the power can be transmitted from a stationary source to wheels. By varying the diameter of input and output gears some of the oscillating devices like steering. This has a wide with respect to each other, the gear ratio can be altered. For range of application where machine containing multi drives example, the pedals of a normal bicycle can spin all the way can be replaced with the single drive. -
Fastener Design Manual
. _- NASA 'Reference Publication 1228 March 1990 Fastener Design Manual Richard T. Barrett . , :. ? . ,' - ' ' - "'".'-*'" _,'" ' "l ......... ' " • ' ¢ ",;L, NASA Reference Publication 1228 1990 Fastener Design Manual Richard T. Barrett Lewis Research Center Cleveland, Ohio National Aeronautics and Space Administration Office of Management Scientific and Technical Information Division ERRATA NASA Reference Publication 1228 Fastener Design Manual Richard T. Barrett March 1990 The manual describes various platings that may be used for corrosion control including cadmium and zinc plating. It does not mention outgassing problems caused by the relatively high vapor pressure of these metals. The fastener manual was intended primarily for aeronautical applica- tions, where outgassing is typically not a concern. Issued June 17, 2008 Summary ........... ..... ............. ..... ..... ..... ................................ ..... ....... ....... ............. 1 Introduction ... .................. .......... ..... ..... ..... ..... ..... .......... ............ ..... ....... ............... 1 General Design Information Fastener Materials .... ........ ..... ..... ..... ..... ...................... .......... ............ ............ ..... .. 1 Platings and Coatings ... ..... ..... .......... ..... ..... ..... ..... ................. ..... ............ .............. 1 Thread Lubricants ... ....................... ...................... .......... ................. ....... ..... ..... .... 4 Corrosion ........ ..... .................. ..... .... -
Machine Elements: Connecting Elements Gunt
Engineering design 5 Machine elements: connecting elements gunt Machine elements Components of a technical application that fulfi l certain func- Simple machine elements such as screws, cylinder pins, This section presents the following machine elements: tions in structures are known as machine elements. Machine feather keys or seals are defi ned according to standards and • various connecting elements elements can be both single components and assemblies: therefore can be exchanged without diffi culty. More complex • roller bearings machine elements such as bearings, couplings, gears or shafts • various types of gears • individual parts such as screws, bolts or gears are standardised in only certain important properties, such as • assemblies consisting of individual machine elements, such main dimensions or fl anges, and as such are not fully inter- Connecting elements as couplings, ball bearings, transmissions or valves changeable. An individual machine element always performs the same func- Connecting elements are used when the components in the machine are intended to tion, even though it is used in very different structures. be fi xed fi rmly to each other. Fixing screws, rivets and studs are discrete elements that are usually detachable and can be reused. Screws are the most commonly used machine elements and are classifi ed according to Classifi cation of machine elements their function: fastening screws connect two or more parts fi rmly to each other and can be detached. Motion screws convert rotary motion into linear motion and are used Some machine elements can perform different tasks. For example, couplings can be used as linking and/or transmission elements under load following assembly. -
1.0 Simple Mechanism 1.1 Link ,Kinematic Chain
SYLLABUS 1.0 Simple mechanism 1.1 Link ,kinematic chain, mechanism, machine 1.2 Inversion, four bar link mechanism and its inversion 1.3 Lower pair and higher pair 1.4 Cam and followers 2.0 Friction 2.1 Friction between nut and screw for square thread, screw jack 2.2 Bearing and its classification, Description of roller, needle roller& ball bearings. 2.3 Torque transmission in flat pivot& conical pivot bearings. 2.4 Flat collar bearing of single and multiple types. 2.5 Torque transmission for single and multiple clutches 2.6 Working of simple frictional brakes.2.7 Working of Absorption type of dynamometer 3.0 Power Transmission 3.1 Concept of power transmission 3.2 Type of drives, belt, gear and chain drive. 3.3 Computation of velocity ratio, length of belts (open and cross)with and without slip. 3.4 Ratio of belt tensions, centrifugal tension and initial tension. 3.5 Power transmitted by the belt. 3.6 Determine belt thickness and width for given permissible stress for open and crossed belt considering centrifugal tension. 3.7 V-belts and V-belts pulleys. 3.8 Concept of crowning of pulleys. 3.9 Gear drives and its terminology. 3.10 Gear trains, working principle of simple, compound, reverted and epicyclic gear trains. 4.0 Governors and Flywheel 4.1 Function of governor 4.2 Classification of governor 4.3 Working of Watt, Porter, Proel and Hartnell governors. 4.4 Conceptual explanation of sensitivity, stability and isochronisms. 4.5 Function of flywheel. 4.6 Comparison between flywheel &governor. -
Bolted Timber Joints with Self-Tapping Screws
Revista EIA, ISSN 1794-1237 Número 8, p. 37-47. Diciembre 2007 Escuela de Ingeniería de Antioquia, Medellín (Colombia) BOLTED TIMBER JOINTS WITH SELF-TAPPING SCREWS CÉSAR ECHAVARRÍA* ABSTRACT The use of self-tapping screws with continuous threads in the joint area as a reinforcement to avoid splitting of timber members is studied. A theoretical model is developed to calculate the stress distribution around a pin-loaded hole in a timber joint, to predict brittle failure modes in bolted connections and to cal- culate the load in the reinforcing screws. Laboratory experiments on reinforced and non-reinforced timber joints with 15,9-mm bolts have shown good agreement with the model predictions. KEYWORDS: timber joints; brittle failure mode; reinforcement perpendicular-to-grain; analytical model. RESUMEN En este artículo se estudia el uso de tornillos autoperforantes como refuerzo para evitar rupturas frágiles en uniones de madera. Se presenta un modelo teórico para calcular la distribución de esfuerzos alrededor de un perno en una unión de madera, predecir las rupturas frágiles y evaluar el esfuerzo en los tornillos autoperforantes. Los ������������������������������������������������������������������������experimentos de laboratorio con uniones de madera, con pernos de 15,9 mm de diámetro, reforzadas y no reforzadas mostraron la efectividad del modelo teórico propuesto. PALABRAS CLAVE: uniones de madera; ruptura frágil; refuerzo perpendicular a las fibras; modelo analítico. * Ingeniero Civil, Universidad Nacional de Colombia; Master in Timber Structures and Docteur en Sciences, École Polytechnique Fédérale de Lausanne, Switzerland. Ph.D. Researcher, Département des sciences du bois et de la forêt, Université Laval, Québec. [email protected] Associate Professor, Faculty of Architecture, School of Construction, Universidad Nacional de Colombia. -
Bolted Joint Design
Bolted Joint Design There is no one fastener material that is right for every environment. Selecting the right fastener material from the vast array of those available can be a daunting task. Careful consideration must be given to strength, temperature, corrosion, vibration, fatigue, and many other variables. However, with some basic knowledge and understanding, a well thought out evaluation can be made. Mechanical Properties of Steel Fasteners in Service Most fastener applications are designed to support or transmit some form of externally applied load. If the strength of the fastener is the only concern, there is usually no need to look beyond carbon steel. Considering the cost of raw materials, non-ferrous metals should be considered only when a special application is required. Tensile strength is the mechanical property most widely associated with standard threaded fasteners. Tensile strength is the maximum tension-applied load the fastener can support prior to fracture. The tensile load a fastener can withstand is determined by the formula P = St x As . • P= Tensile load– a direct measurement of clamp load (lbs., N) • St= Tensile strength– a generic measurement of the material’s strength (psi, MPa). • As= Tensile stress area for fastener or area of material (in 2, mm 2) To find the tensile strength of a particular P = St x As bolt, you will need to refer to Mechanical P = tensile load St = tensile strength As = tensile stress area Properties of Externally Threaded Fasteners (lbs., N) (psi, MPa) (sq. in, sq. mm) chart in the Fastenal Technical Reference Applied to a 3/4-10 x 7” SAE J429 Grade 5 HCS Guide. -
Engineering Design
A111D3 Qfifi^3H NATL INST OF STANDARDS & TECH R.I.C. gineering design : }77 C.1 NBS-PUB-C 19 NBS SPECIAL PUBLICATION 487 U.S. DEPARTMENT OF COMMERCE / National Bureau of Standards Engineering Design MFPG 25th Meeting - r»iT--ti>ii-J'fittMni i;f iiff ii i>i<tiiii m NATIONAL BUREAU OF STANDARDS The National Bureau of Standards^ was established by an act of Congress March 3, 1901. The Bureau's overall goal is strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to pro- mote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, the Institute for Computer Sciences and Technology, the Office for Information Programs, and the Office of Experimental Technology Incentives Program. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consist- ent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essen- tial services leading to accurate and uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of the Office of Measurement Services, and the following center and divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Center for Radiation Research — Lab- oratory Astrophysics^ — Cryogenics^ — Electromagnetics'' — Time and Frequency".