DOCSLIB.ORG

Biaxial Testing of Sheet Metal: an Experimental-Numerical Analysis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Biaxial Testing of Sheet Metal: an Experimental-Numerical Analysis Biaxial Testing of Sheet Metal: An Experimental-Numerical Analysis Gerard Quaak MT 08.10 TU/e Master Thesis May, 2008 Engineering thesis committee prof.dr.ir. M.G.D. Geers (Chairman) dr.ir. J.P.M. Hoefnagels (Coach) ir. C. Tasan (Coach) dr.ir. P.J.G. Schreurs dr.ir. H. Vegter Eindhoven University of Technology Department of Mechanical Engineering Computational and Experimental Mechanics Abstract With the recent increase in the popularity of advanced high strength steels (e.g. dual phase, TRIP) in automotive industry, new challenges have arisen. Conventional continuum models are found not to capture the reported pre- mature ductile failures in such steels, which are governed by damage evolution. Another challenge is understanding and predicting metal behaviour under com- plex strain paths. The ability to precisely capture these eects in continuum models is important for the sheet metal forming industry, in order to carry out these processes as ecient as possible. However, improvements of the numerical tools highly depend on the development of accurate and practical experimental techniques. A testing device for biaxial deformation of sheet metal is such an experimental tool that has been studied by many researchers before. Although several experimental set-ups have been proposed in the literature, most of these designs are not capable of providing information up to the point of fracture. Additionally, these set-ups are not usable for real-time, in-situ examination of the deforming structure with advanced microscopic techniques such as SEM, AFM, surface prolometry, or digital image correlation, because a miniaturized form is not available or was never investigated. The main goal of this project therefore is to nd a practical and accurate set- up that can deform sheet metal specimens under varying complex strain paths, while allowing for real-time, in-situ microscopic examination. For this pur- pose, several experimental set-ups (e.g. bulge, punch, Marciniak and cruciform tests) have been studied and compared both experimentally and numerically. For testing cruciform samples a simplied in-plane biaxial-loading set-up was designed and build, while Marciniak tests were carried out at Corus RD&T. The corresponding experimental results were used to verify and compare these tests in terms of practical aspects (e.g. specimen preparation). The computa- tional results are used to analyze stress and strain distributions and for better understanding of the eects of miniaturization. Combining literature, numerical and experimental test results, it was concluded that the cruciform and Marciniak test are the most promising set-ups for minia- turized biaxial testing of sheet metal with in-situ microscopic examination. Both test have their limits, but when taken these into account can provide valuable data. i Samenvatting Met de recente populariteit van 'advanced high strength' staalsoorten (dual phase, TRIP) in de automotive industrie, zijn nieuwe vraagstukken ontstaan. Conventionele continuum modellen blijken niet in staat om de aanwezige taaie breuk te beschrijven, waardoor het voorspellen van het materiaal gedrag tijdens omvormen van deze metalen niet mogelijk blijkt. Wanner niet lineaire rek paden een rol spelen blijken de huidige continuum modellen zelfs nog minder accuraat. Voor het verbeteren van de numerieke gereedschappen zijn echter betrouwbare experimentele technieken nodig, zodat het materiaal gedrag voor deze groep metalen is te bepalen. Een voorbeeld van zo een opstelling, is er een om biaxiale deformatie van plaat staal te bestuderen. Hiernaar is reeds veel onderzoek aan besteed, maar hoewel verschillende gereedschappen onderzocht zijn, bestaat er tot op heden geen opstelling om tot breuk te deformeren zonder externe invloeden. Daar komt nog bij dat om de micro structuur van het materiaal te onderzoeken geavanceerde technieken als SEM en AFM of digital image correlation gebruikt moeten worden, wat inhoudt dat een miniatuur opstelling nodig is. Mogelijkheden voor een dergelijke opstelling zijn nog niet eerder onderzocht. Het belangrijkste doel van dit project is dan ook het vinden van een praktische manier om plaat staal onder veranderende rek paden, met de mogelijkheid real- time metingen te doen. Hiervoor zijn verschillende experimentele opstellingen (bulge, punch, Marciniak en cruciform test) numeriek en experimenteel onder- zocht en vergeleken. De numerieke resultaten geven o.a. inzicht in spannings- en rek velden en de eecten van miniaturisatie, de experimentele resultaten worden gebruikt voor vericatie en vergelijk op praktische gebied, zoals het maken van test samples. Voor het testem van kruisvormige trekstaven is een opstelling ontworpen en gebouwd, als onderdeel van dit onderzoek. Voor de Marciniak testen is gebruik gemaakt van een opstelling beschikbaar gesteld door Corus RD&T. De literatuur studie, numerieke en experimentele resultaten laten zien dat zowel de kruisvormige trekstaven als de Marciniak test bruikbaar zijn in een geminia- turiseerde vorm. Beide tests hebben beperkingen, maar wanneer hier rekening mee wordt gehouden kunnen zij waardevolle informatie opleveren. ii Acknowledgement This Master project was mainly carried out at Eindhoven University of Tech- nology, in the group of professor Marc Geers. Experimental work has been done at Corus RD&T in IJmuiden and in the University Multi-scale Labora- tory. Special thanks goes to Sjef Garenfeld for his time and patience in the design process of the biaxial testing set-up and specimens. I also want to thank Marc van Maris, supervisor of the Multi-scale Laboratory, for his guidance and advice during experimental work and Tom Engels for his help with the tensile testing machine. From I want to thank Corus RD&T Menno de Bruine, oper- ator of the Marciniak test set-up, Carel ten Horn and Louisa Carless for their time and eort with the experimental work on the Marciniak test. At Philips Drachten a lot of insight was provided in possible material removal techniques, for which I want to express my gratitude to Gerrit Klaseboer, Harmen Altena and Willem Hoogsteen for receiving us and a good discussion of the material removal problem. I also want to thank Johan Hoefnagels and Cem Tasan for their input in the project, the many evenings discussing and the help with the nal report. Gerard Quaak Eindhoven, May 2008 iii Contents Abstract i Samenvatting ii 1 Introduction 1 1.1 Formability and strain path dependency . 2 1.2 Objective . 4 1.3 Strategy . 4 2 Literature Survey 5 2.1 Introduction . 5 2.2 Bulge test . 8 2.3 Punch test . 11 2.4 Marciniak test . 14 2.5 In-plane loading with cruciform geometry . 17 2.6 Summary . 22 3 Numerical methodology 23 3.1 Material model . 23 3.2 Bulge test . 24 3.3 Punch test . 25 3.4 Marciniak test . 27 3.5 In-plane loading with cruciform geometry . 28 4 Experimental methodology 29 4.1 Marciniak test . 29 4.1.1 In-plane testing with the Marciniak set-up . 29 4.1.2 Specimen manufacturing . 30 4.2 In-plane loading with cruciform geometry . 30 4.2.1 Design of a test set-up . 30 4.2.2 Tests with in-plane cruciform geometry . 34 4.2.3 Specimen manufacturing and characterization . 36 5 Results 39 5.1 Bulge test . 40 5.1.1 Miniaturization . 40 5.1.2 Summary . 42 5.2 Punch test . 43 iv CONTENTS 5.2.1 Miniaturization . 44 5.2.2 Summary . 46 5.3 Marciniak test . 47 5.3.1 Working principle of the Marciniak test . 47 5.3.2 Numerical - experimental study of the Marciniak test . 49 5.3.3 Minaturization . 53 5.3.4 Summary . 55 5.4 In-plane loading with cruciform geometry . 56 5.4.1 Optimization of the cruciform design . 56 5.4.2 Proof of principle . 57 5.4.3 Specimen manufacturing and characterization . 60 5.4.4 Miniaturization . 66 5.4.5 Summary . 67 5.5 Comparative evaluation of the set-ups . 68 6 Conclusions and recommendations 72 6.1 Conclusions . 72 6.2 Recommendations for future work . 73 Bibliography 75 A Electrical Discharge Machining 79 B Electrical Chemical Machining (ECM) 83 C Specimen Preparation: TegraPol or Target System 86 v Chapter 1 Introduction Metals, and in particular sheet metals, are used in a wide variety of appli- cations in industry, with the main elds of application being packaging (food containers, beverage cans), automotive and aerospace industry. As material costs are a substantial part of the costs of manufactured products and most of the products are produced in large numbers, large cost reductions can be achieved by lowering the amount of material used. Moreover, several other reasons that can be thought of for lowering the amount of used material, e.g. lowering weight and lowering impact on the environment by polluting. All of these reasons result in eorts to achieve material use reduction without quality loss in the product. Figure 1.1: Advantages and disadvantages of using aluminium instead of steel for a standard medium size car [44] In the automobile industry a rst attempt to achieve weight reduction was done by using low density materials like aluminium, magnesium and plastics, but recent studies show a promising future for steels instead. The International Iron and Steel Institute (IISI) computed how the use of aluminium makes the car body lighter, but does not have a signicant eect on the total weight of the car and causing more environmental impact because of higher equivalent CO2-emissions (see gure 1.1). The development of Advanced High Strength Steels that can replace the existing steels is therefore closely followed by the automotive industry. [16, 44] 1 CHAPTER 1. INTRODUCTION Figure 1.2: Overview of steel grades as used in the automotive industry [44] Figure 1.2 shows an overview of regularly used types of steel for automotive applications. In this gure the materials furthest to the left are most suitable for forming virtually any desired shape, while consuming relative low amounts of energy.
Load more

Recommended publications
  • Improving Plastics Management: Trends, Policy Responses, and the Role of International Co-Operation and Trade
    Improving Plastics Management: Trends, policy responses, and the role of international co-operation and trade POLICY PERSPECTIVES OECD ENVIRONMENT POLICY PAPER NO. 12 OECD . 3 This Policy Paper comprises the Background Report prepared by the OECD for the G7 Environment, Energy and Oceans Ministers. It provides an overview of current plastics production and use, the environmental impacts that this is generating and identifies the reasons for currently low plastics recycling rates, as well as what can be done about it. Disclaimers This paper is published under the responsibility of the Secretary-General of the OECD. The opinions expressed and the arguments employed herein do not necessarily reflect the official views of OECD member countries. This document and any map included herein are without prejudice to the status of or sovereignty over any territory, to the delimitation of international frontiers and boundaries and to the name of any territory, city or area. For Israel, change is measured between 1997-99 and 2009-11. The statistical data for Israel are supplied by and under the responsibility of the relevant Israeli authorities. The use of such data by the OECD is without prejudice to the status of the Golan Heights, East Jerusalem and Israeli settlements in the West Bank under the terms of international law. Copyright You can copy, download or print OECD content for your own use, and you can include excerpts from OECD publications, databases and multimedia products in your own documents, presentations, blogs, websites and teaching materials, provided that suitable acknowledgment of OECD as source and copyright owner is given.
    [Show full text]
  • Multidisciplinary Design Project Engineering Dictionary Version 0.0.2
    Multidisciplinary Design Project Engineering Dictionary Version 0.0.2 February 15, 2006 . DRAFT Cambridge-MIT Institute Multidisciplinary Design Project This Dictionary/Glossary of Engineering terms has been compiled to compliment the work developed as part of the Multi-disciplinary Design Project (MDP), which is a programme to develop teaching material and kits to aid the running of mechtronics projects in Universities and Schools. The project is being carried out with support from the Cambridge-MIT Institute undergraduate teaching programe. For more information about the project please visit the MDP website at http://www-mdp.eng.cam.ac.uk or contact Dr. Peter Long Prof. Alex Slocum Cambridge University Engineering Department Massachusetts Institute of Technology Trumpington Street, 77 Massachusetts Ave. Cambridge. Cambridge MA 02139-4307 CB2 1PZ. USA e-mail: [email protected] e-mail: [email protected] tel: +44 (0) 1223 332779 tel: +1 617 253 0012 For information about the CMI initiative please see Cambridge-MIT Institute website :- http://www.cambridge-mit.org CMI CMI, University of Cambridge Massachusetts Institute of Technology 10 Miller’s Yard, 77 Massachusetts Ave. Mill Lane, Cambridge MA 02139-4307 Cambridge. CB2 1RQ. USA tel: +44 (0) 1223 327207 tel. +1 617 253 7732 fax: +44 (0) 1223 765891 fax. +1 617 258 8539 . DRAFT 2 CMI-MDP Programme 1 Introduction This dictionary/glossary has not been developed as a definative work but as a useful reference book for engi- neering students to search when looking for the meaning of a word/phrase. It has been compiled from a number of existing glossaries together with a number of local additions.
    [Show full text]
  • TSCA Inventory Representation for Products Containing Two Or More
    mixtures.txt TOXIC SUBSTANCES CONTROL ACT INVENTORY REPRESENTATION FOR PRODUCTS CONTAINING TWO OR MORE SUBSTANCES: FORMULATED AND STATUTORY MIXTURES I. Introduction This paper explains the conventions that are applied to listings of certain mixtures for the Chemical Substance Inventory that is maintained by the U.S. Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA). This paper discusses the Inventory representation of mixtures of substances that do not react together (i.e., formulated mixtures) as well as those combinations that are formed during certain manufacturing activities and are designated as mixtures by the Agency (i.e., statutory mixtures). Complex reaction products are covered in a separate paper. The Agency's goal in developing this paper is to make it easier for the users of the Inventory to interpret Inventory listings and to understand how new mixtures would be identified for Inventory inclusion. Fundamental to the Inventory as a whole is the principle that entries on the Inventory are identified as precisely as possible for the commercial chemical substance, as reported by the submitter. Substances that are chemically indistinguishable, or even identical, may be listed differently on the Inventory, depending on the degree of knowledge that the submitters possess and report about such substances, as well as how submitters intend to represent the chemical identities to the Agency and to customers. Although these chemically indistinguishable substances are named differently on the Inventory, this is not a "nomenclature" issue, but an issue of substance representation. Submitters should be aware that their choice for substance representation plays an important role in the Agency's determination of how the substance will be listed on the Inventory.
    [Show full text]
  • An Experimental and Modeling Study of the Viscoelastic Behavior Of
    ð þ1 t An Experimental and Modeling rðÞ¼t re þ rsðÞexp À ds (1) Study of the Viscoelastic Behavior 0 s of Collagen Gel In Eq. (1), re is the equilibrium stress, and r(s) is the relaxation time distribution function with relaxation time s. Viscoelastic biomaterials likely contain a continuous spectrum Bin Xu of relaxation time constants [5]. While Eq. (1) can be well fitted with a few exponential terms, the fitting may provide little infor- Haiyue Li mation relevant to the characterization of intrinsic material prop- erties [6]. In the present study, the time-dependent distribution spectrum r(s) of collagen gel is obtained through numerical Department of Mechanical Engineering, inverse Laplace transform. Investigating the spectrum in terms of Boston University, the number of peaks, time constants, and peak intensity was found 110 Cummington Mall, to appropriately demonstrate the main properties of viscoelastic Boston, MA 02215 behaviors [7,8]. The intensity of the peak reflects the amount of dissipated energy during relaxation. The number of peaks and time constants are often correlated with specific molecular archi- Yanhang Zhang1 tectures; as a result it can be used as an approach to understand the structural behavior of biomaterials, as well as a useful tool to Associate Professor distinguish materials [9,10]. Department of Mechanical Engineering, In this study, the relaxation time distribution spectrum is Department of Biomedical Engineering, obtained from stress relaxation data by means of inverse Laplace Boston University, transform. This spectrum is employed to understand the mecha- 110 Cummington Mall, nisms of stress relaxation in collagen network.
    [Show full text]
  • Chapter 2 the Solid Materials of the Earth's Surface
    CHAPTER 2 THE SOLID MATERIALS OF THE EARTH’S SURFACE 1. INTRODUCTION 1.1 To a great extent in this course, we will be dealing with processes that act on the solid materials at and near the Earth’s surface. This chapter might better be called “the ground beneath your feet”. This is the place to deal with the nature of the Earth’s surface materials, which in later sections of the chapter I will be calling regolith, sediment, and soil. 1.2 I purposely did not specify any previous knowledge of geology as a prerequisite for this course, so it is important, here in the first part of this chapter, for me to provide you with some background on Earth materials. 1.3 We will be dealing almost exclusively with the Earth’s continental surfaces. There are profound geological differences between the continents and the ocean basins, in terms of origin, age, history, and composition. Here I’ll present, very briefly, some basic things about geology. (For more depth on such matters you would need to take a course like “The Earth: What It Is, How It Works”, given in the Harvard Extension program in the fall semester of 2005– 2006 and likely to be offered again in the not-too-distant future.) 1.4 In a gross sense, the Earth is a layered body (Figure 2-1). To a first approximation, it consists of concentric shells: the core, the mantle, and the crust. Figure 2-1: Schematic cross section through the Earth. 73 The core: The core consists mostly of iron, alloyed with a small percentage of certain other chemical elements.
    [Show full text]
  • Review of Thermal Properties of Graphene and Few-Layer
    Zhong Yan, Denis L. Nika and Alexander A. Balandin (invited review, submitted in 2014) INVITED REVIEW PAPER Review of Thermal Properties of Graphene and Few-Layer Graphene: Applications in Electronics Zhong Yan1, Denis L. Nika1,2 and Alexander A. Balandin1,3 1Nano-Device Laboratory, Department of Electrical Engineering and Materials Science and Engineering Program, Bourns College of Engineering, University of California – Riverside, Riverside, California, 92521 USA 2E. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Department of Physics and Engineering, Moldova State University, Chisinau, MD-2009, Republic of Moldova 3Quantum Seed LLC, 1190 Columbia Avenue, Riverside, California 92507 USA Abstract We review thermal properties of graphene and few-layer graphene, and discuss applications of these materials in thermal management of advanced electronics. The intrinsic thermal conductivity of graphene – among the highest of known materials – is dominated by phonons near the room temperature. The examples of thermal management applications include the few-layer graphene heat spreaders integrated near the heat generating areas of the high-power density transistors. It has been demonstrated that few-layer graphene heat spreaders can lower the hot-spot temperature during device operation resulting in improved performance and reliability of the devices. Keywords: graphene, thermal conductivity, heat spreaders, thermal management 1 Zhong Yan, Denis L. Nika and Alexander A. Balandin (invited review, submitted in 2014) I. Introduction Thermal management represents a major challenge in the state-of-the-art electronics due to rapid increase of power densities [1, 2]. Efficient heat removal has become a critical issue for the performance and reliability of modern electronic, optoelectronic, photonic devices and systems.
    [Show full text]
  • Introduction to Material Science and Engineering Presentation.(Pdf)
    Introduction to Material Science and Engineering Introduction What is material science? Definition 1: A branch of science that focuses on materials; interdisciplinary field composed of physics and chemistry. Definition 2: Relationship of material properties to its composition and structure. What is a material scientist? A person who uses his/her combined knowledge of physics, chemistry and metallurgy to exploit property-structure combinations for practical use. What are materials? What do we mean when we say “materials”? 1. Metals 2. Ceramics 3. Polymers 4. Composites - aluminum - clay - polyvinyl chloride (PVC) - wood - copper - silica glass - Teflon - carbon fiber resins - steel (iron alloy) - alumina - various plastics - concrete - nickel - quartz - glue (adhesives) - titanium - Kevlar semiconductors (computer chips, etc.) = ceramics, composites nanomaterials = ceramics, metals, polymers, composites Length Scales of Material Science • Atomic – < 10-10 m • Nano – 10-9 m • Micro – 10-6 m • Macro – > 10-3 m Atomic Structure – 10-10 m • Pertains to atom electron structure and atomic arrangement • Atom length scale – Includes electron structure – atomic bonding • ionic • covalent • metallic • London dispersion forces (Van der Waals) – Atomic ordering – long range (metals), short range (glass) • 7 lattices – cubic, hexagonal among most prevalent for engineering metals and ceramics • Different packed structures include: Gives total of 14 different crystalline arrangements (Bravais Lattices). – Primitive, body-centered, face-centered Nano Structure – 10-9 m • Length scale that pertains to clusters of atoms that make up small particles or material features • Show interesting properties because increase surface area to volume ratio – More atoms on surface compared to bulk atoms – Optical, magnetic, mechanical and electrical properties change Microstructure – 10-6 • Larger features composed of either nanostructured materials or periodic arrangements of atoms known as crystals • Features are visible with high magnification in light microscope.
    [Show full text]
  • Phonons in Graphene and Van Der Waals Materials
    Phonons in Graphene and van der Waals Materials Alexander A. Balandin Department of Electrical Engineering and Materials Science and Engineering Program University of California – Riverside MRS Medal Talk Fall 2013 Nano-Device Laboratory (NDL) Department of Electrical Engineering University of California – Riverside Profile: experimental and theoretical research in advanced materials and nano-devices Nanoscale Characterization PI: Alexander A. Balandin Phononics Research Thermal and Electrical & Applications Characterization Electronic Devices and Circuits Theory and Modeling Direct Energy Conversion Device Design and Raman, Fluorescence Characterization and PL Spectroscopy Optoelectronics Bio- Nanotech Alexander A. Balandin, University of California - Riverside Outline Introduction and Basic Definitions Phonons Thermal conductivity Thermal Conductivity of Graphene Raman spectroscopy Optothermal technique Theoretical interpretation Graphene Thermal Applications TIMs and PCMs Heat spreaders Phonons in van der Waals Materials Raman metrology Charge-density waves Outlook: Phononics and Phonon Engineering 3 Alexander A. Balandin, University of California - Riverside Practical Motivations: Why Material Scientists Should Study Thermal Properties? Data is after R. Mahajan et al., Proceed. IEEE (2006) No BIG fan solutions! The switch to multi-core designs alleviates the growth in the thermal design power (TDP) IEEE Spectrum illustration of the increase but does not solve the thermal issues in the feature hot-spot problem article Chill Out: New Materials and Designs Can Keep Chips Non-uniform power densities Cool by A.A. Balandin. leading to hot-spots (>500 W/cm2) Alexander A. Balandin, University of California - Riverside Basics of Phonons The quantum of the energy of a lattice vibration is called a phonon in analogy with the photon of the electromagnetic wave.
    [Show full text]
  • Glossary of Materials Engineering Terminology
    Glossary of Materials Engineering Terminology Adapted from: Callister, W. D.; Rethwisch, D. G. Materials Science and Engineering: An Introduction, 8th ed.; John Wiley & Sons, Inc.: Hoboken, NJ, 2010. McCrum, N. G.; Buckley, C. P.; Bucknall, C. B. Principles of Polymer Engineering, 2nd ed.; Oxford University Press: New York, NY, 1997. Brittle fracture: fracture that occurs by rapid crack formation and propagation through the material, without any appreciable deformation prior to failure. Crazing: a common response of plastics to an applied load, typically involving the formation of an opaque banded region within transparent plastic; at the microscale, the craze region is a collection of nanoscale, stress-induced voids and load-bearing fibrils within the material’s structure; craze regions commonly occur at or near a propagating crack in the material. Ductile fracture: a mode of material failure that is accompanied by extensive permanent deformation of the material. Ductility: a measure of a material’s ability to undergo appreciable permanent deformation before fracture; ductile materials (including many metals and plastics) typically display a greater amount of strain or total elongation before fracture compared to non-ductile materials (such as most ceramics). Elastic modulus: a measure of a material’s stiffness; quantified as a ratio of stress to strain prior to the yield point and reported in units of Pascals (Pa); for a material deformed in tension, this is referred to as a Young’s modulus. Engineering strain: the change in gauge length of a specimen in the direction of the applied load divided by its original gauge length; strain is typically unit-less and frequently reported as a percentage.
    [Show full text]
  • Mechanical Characterisation of Hydrogels for Tissue Engineering
    CHAPTER 12 Mechanical Characterisation of Hydrogels for Tissue Engineering Applications M. Ahearne*, Y. Yang and K-K Liu Summary ydrogels have been extensively investigated for use as constructs to engineer tissues in-vitro. Among the principal limitations with using hydrogels for engineering tissues are their poor mechanical H characteristics. Many techniques exist to measure the mechanical properties of hydrogels but few allow non-destructive monitoring of these propertie s under cells culture conditions. Two recently developed techniques shall be discussed in detail in the current chapter. Thin hydrogels have been clamped around their outer edge and deformed using a spherical load. The time-dependent deformation has been measured in-situ using a long focal distance microscope connected to a CCD camera and the deformation displacement has been used with a theoretical model to quantify the mechanical and viscoelastic properties of the hydrogels. For thicker hydrogels, optical coherence tomography has been used to measure the time-dependent depth of indentation caused by a spherical load on top of the hydrogel. Hertz contact theory has been applied to calculate the hydrogels mechanical properties. The mechanical and viscoelastic properties of several different hydrogel materials were examined. The principal advantages of these techniques have over conventional mechanical characterisation techniques are that the measurement can be performed on cell-seeded hydrogels and under sterile conditions while allowing non-destructive, in-situ and real-time examination of the changes in mechanical properties. KEYWORDS: Hydrogel, Mechanical characterisation, Indentation, Viscoelastic, Optical coherence tomography. *Correspondence to: Tel.: +44 (0)1782 555227. Fax: +44 (0)1782 717079. E-mail address: [email protected].
    [Show full text]
  • System for the Application of Hydrostatic Pressure and Mechanical Strain to Cell Cultures Justin Bacaoat Clemson University, [email protected]
    Clemson University TigerPrints All Theses Theses 12-2018 System for the Application of Hydrostatic Pressure and Mechanical Strain to Cell Cultures Justin Bacaoat Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Recommended Citation Bacaoat, Justin, "System for the Application of Hydrostatic Pressure and Mechanical Strain to Cell Cultures" (2018). All Theses. 2966. https://tigerprints.clemson.edu/all_theses/2966 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. SYSTEM FOR THE APPLICATION OF HYDROSTATIC PRESSURE AND MECHANICAL STRAIN TO CELL CULTURES A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Bioengineering by Justin Bacaoat December 2018 Accepted by: Jiro Nagatomi, PhD, Committee Chair William Richardson, PhD Ken Webb, PhD ABSTRACT Pressure and stretch are two of the primary forces that result in mechanotransductory events which regulate certain aspects of human health and disease. Laboratory systems such as the commercially available Flexercell® system and a variety of custom-made setups are currently used in research to systematically apply stretch and hydrostatic pressure independently, or in conjunction to cell and tissue cultures. However, these systems do not allow for the decoupling of pressure and stretch under the same culture conditions. The present study aims to design, fabricate, and calibrate a device that can apply pressure and stretch simultaneously, as well as independently to cells in culture.
    [Show full text]
  • Composite Materials Prof
    COMPOSITE MATERIALS PROF. R. VELMURUGAN Composite Materials Module I - Introduction Lectures 1 to 2 Introduction Composite materials have changed the world of materials revealing materials which are different from common heterogeneous materials. A composite material is a structural material that consists of two or more combined constituents which are combined at macroscopic level and are not soluble in each other. It should be understood that the aforesaid composite material is not the by-product of any chemical reaction between two or more of its constituents. One of its constituents is called the reinforcing phase and the other one, in which the reinforcing phase material is embedded, is called the matrix. The reinforcing phase material may be in the form of fibers, particles, or flakes (e.g. Glass fibers). The matrix phase materials are generally continuous (e.g. Epoxy resin). The matrix phase is light but weak. The reinforcing phase is strong and hard and may not be light in weight. For example, in concrete reinforced with steel the matrix phase is concrete and the reinforcing phase is steel. In graphite/epoxy composites the graphite fibers are the reinforcing phase and the epoxy resin is the matrix phase. A material shall be considered as a composite material if it satisfies the following conditions: 1. It is manufactured i.e., excluding naturally available composites. 2. It consists of two or more physically and/or chemically distinct, suitably arranged or distributed phases with an interface separating them. 3. It has characteristics that are not the replica of any of the components taken individually.
    [Show full text]