Dissertations / Theses on the topic 'Shape deformation'
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Piazolo, Sandra. "Shape fabric development during progressive deformation." [S.l. : s.n.], 2000. http://ArchiMeD.uni-mainz.de/pub/2001/0032/diss.pdf.
Full textAngelidis, Alexis, and n/a. "Shape modeling by swept space deformation." University of Otago. Department of Computer Science, 2006. http://adt.otago.ac.nz./public/adt-NZDU20060808.161349.
Full textMei, Lin. "Statistical analysis of shape and deformation." Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542932.
Full textSeaton, Alexander B. "Thermomechanical deformation of shape memory alloys." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/20317.
Full textIto, Hiroaki. "Shape fluctuation and deformation of biological soft interfaces." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215286.
Full textFender, Amanda. "Shape and deformation measurement using multicore optical fibres." Thesis, Heriot-Watt University, 2008. http://hdl.handle.net/10399/2058.
Full textPerez, Daniel Eduardo. "Shield Design for Maximum Deformation in Shape-Shifting Surfaces." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4561.
Full textRajagopalan, Sudhir. "INSTRUMENTED NANOINDENTATION STUDIES OF DEFORMATION IN SHAPE MEMORY ALLOYS." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3283.
Full textPh.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
Feng, Ping. "Deformation instability and morphology in shape memory alloy under stress /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MECH%202005%20FENG.
Full textBlanco, Fausto Richetti. "A technique for interactive shape deformation on non-structured objects." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/11176.
Full textThis work presents a technique for interactive shape deformation of unstructured 3D models, based on 2D sketches and interactive curve manipulation in 3D. A set of lines sketched on the image plane over the projection of the model can be combined to create a skeleton composed by parametric curves, which can be interactively manipulated, thus deforming the associated surfaces. Free-form deformations are performed by interactively moving around the curves’ control points. Some other interesting effects, such as twisting and scaling, are obtained by operating directly over a frame field defined on the curve. An algorithm for mesh local self-intersection avoidance during model deformation is also presented. This algorithm is executed at interactive rates as is the whole technique presented in this work. The presented technique naturally handles both translations and large rotations, as well as non-orientable and non-manifold surfaces, and meshes comprised of multiple components. In all cases, the deformation preserves local features. The use of skeleton curves allows the technique to be implemented using a very intuitive interface, and giving the user fine control over the deformation. Skeleton constraints and local self-intersection avoidance are easily achieved. High-quality results on twisting and bending meshes are also demonstrated, and the results show that the presented technique is considerably faster than previous approaches for achieving similar results. Given its relatively low computational cost, this approach can handle meshes composed by hundreds of thousand vertices at interactive rates.
Nguyen, Tran. "Optical measurement of shape and deformation fields on challenging surfaces." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10551.
Full textNeophytou, Alexandros. "Data driven models of human shape, pose and garment deformation." Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/808505/.
Full textShao, Wei. "Identifying the shape collapse problem in large deformation image registration." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2276.
Full textDaieff, Marine. "Deformation and shape of flexible, microscale helices in viscous flows." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC189/document.
Full textFluid-structure interactions are of wide interest in engineering, industrial and medical applications. Understanding the interactions between complex shaped particles and flows might lead to new designs for targeted delivery, microflow sensors and to a better understanding of the behavior of microorganisms. In this thesis, we study the fluid-structure interaction of microscale chiral particles at low Reynolds numbers. The particles are rigid and confined in a 2D geometry or flexible with a helical shape. The combination of microfabrication techniques, such as multiscale assembly methods and microfluidics, enables to have a perfect control on both the geometrical and mechanical properties of the fibers and the flow features such as Newtonian or non Newtonian properties, the flow velocity and the flow geometry. First we studied asymmetric 2D rigid fibers, i.e. L-shaped fibers. Both lateral and transversal confinements have been investigated, as well as the shape of the fiber. When the particle is transported in viscous flows, it rotates until reaching an equilibrium orientation. In this specific orientation, the fiber drifts towards the lateral walls of the channel. A full investigation on the trajectories of the fiber has been performed and comparisons with symmetric particles have been done. Such research may help design devices to sort particles for medical purposes. Secondly we studied flexible microscale helical fibers. The dynamics of the helix formation has been investigated. The helices are formed from straight 2D ribbons, which spontaneously coil when released in water. The helical shape is reached only several minutes after the release but the helix keeps shrinking during several hours until reaching a preferred curvature. Two different timescales are identified in this formation dynamics. A model has been developed to understand the complex balance between elastic, surface tension and viscous forces at short times. After investigating several assumptions such as the impact of a sacrificial layer, a possible change in the modulus of the material and a creep behavior, the evolution of the radius at long times is most likely explained by creep. The extension and relaxation dynamics of the flexible fiber has also been studied in Newtonian and non Newtonian fluids. The study in polymer solutions is relevant and interesting because the size of the microhelix is comparable to the flagella of microorganisms and to the chains of high molecular weight polymers. Complex multiscale problems are then involved as the local viscosity at the scale of the ribbon might differ from the global viscosity at the scale of the flow
Xu, Ying. "A new constrained shape deformation operator with applications in footwear design /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?IELM%202008%20XU.
Full textNordén, Kristina. "Surface and Inner Deformation during Shape Rolling of High Speed Steels." Licentiate thesis, KTH, Materials Science and Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4460.
Full textShape rolling is a common manufacturing process used to produce long products i.e. bars and wire. One of the problems that might occur during rolling is defect formation leading to rejection of the finished product. This work is a step towards a better understanding of the evolution of some of these defects.
The evolution and reduction of cracks during shape rolling is studied in this thesis. To accomplish this, artificial longitudinal cracks are machined along bars of high speed steel. The cracks are positioned at different sites evenly distributed along the periphery in intervals of 45°. Some of the cracks are left open and some are filled with carbon or stainless steel welds. FE simulations are performed using the commercial code MSC.Marc and the results from the simulations are compared with experimental ones. Generally, simulations predict less reduction than observed experimentally. For most positions, the cracks tend to reduce most effectively followed by carbon steel welds and stainless steel welds.
To evaluate the inner deformation of a cross section during shape rolling in an oval-round-oval-round series, sample bars of M2 high speed steel are prepared with grids made up by stainless steel wires. After collecting samples after each pass, they are X-rayed to create an image of the grid. The deformation of the wires can favorably be described by FE simulations of a bar originally rotated 10° when entering the first pass. The results suggest that the simulations describe the deformation during shape rolling well.
Nordén, Kristina. "Surface and inner deformation during shape rolling of high speed steels /." Stockholm : Materialvetenskap Materials Science and Engineering, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4460.
Full textNardoni, Chiara. "Mesh deformation strategies in shape optimization. Application to forensic facial reconstruction." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066248/document.
Full textThis thesis is devoted to the conception, the development and the analysis of mesh deformation strategies for shape modeling, processing and comparison -as shape matching and surface reconstruction- and, in a rather independent concern, for devising a robust computational method for facial reconstruction. Facial reconstruction is about the estimation of a facial shape from the sole datum of the underlying skull and is a challenging problem in anthropology and forensic science. The main contribution of the thesis is the design of a novel method for shape matching, borrowing techniques from the shape optimization context. Under the sole assumption that the two shapes share the same topology, the desired mapping is achieved as a sequence of elastic displacements by minimizing an energy functional based on a signed distance function. Several numerical examples are presented to show the efficiency of the method.Also, a novel method for generating a closed surface mesh model of an initially non-closed source mesh model is developed. The method relies on an original PDE-based mesh evolution technique. A template shape is iteratively deformed, producing a sequence of shapes that get 'closer and closer' to the source triangulation.The second part of the manuscript deals with the development of a landmark-free, fully automated method for digital facial reconstruction. Based on techniques of continuous deformation as 'morphing' and 'warping', the proposed approach is integrated with anthropological assumptions and mechanical models
ROUSSEAU, Yannick, Igor MEN'SHOV, and Yoshiaki NAKAMURA. "Morphing-Based Shape Optimization in Computational Fluid Dynamics." 日本航空宇宙学会, 2007. http://hdl.handle.net/2237/13876.
Full textHe, Yongjun. "Non-local model for deformation patterns in NiTi microtubing /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MECH%202005%20HE.
Full textRaji, Abdulganiy Olayinka. "Discrete element modelling of the deformation of bulk agricultural particulates." Thesis, University of Newcastle Upon Tyne, 1999. http://hdl.handle.net/10443/871.
Full textRATHOD, CHANDRASEN. "DIFFRACTION STUDIES OF DEFORMATION IN SHAPE MEMORY ALLOYS AND SELECTED ENGINEERING COMPONENTS." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2892.
Full textPh.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
Wang, Liu Sheng. "Shape and deformation measurement of 3D surface using phase stepping speckle interferometry." Thesis, Nottingham Trent University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386409.
Full textJi, Wei. "Spatial Partitioning and Functional Shape Matched Deformation Algorithm for Interactive Haptic Modeling." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1226364059.
Full textKulkarni, Ajay V. "Effect of ausforming via severe plastic deformation on shape memory behavior of NiTi." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/3246.
Full textHong, Sung Min. "Shape Modeling of Plant Leaves with Unstructured Meshes." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1182.
Full textValencia, Angel. "3D Shape Deformation Measurement and Dynamic Representation for Non-Rigid Objects under Manipulation." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40718.
Full textSimon, Anish Abraham. "Shape memory response and microstructural evolution of a severe plastically deformed high temperature shape memory alloy (NiTiHf)." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/3139.
Full textNilsson, Bengt. "Interferometric 3-D Camera for Shape and Deformation Measurements using Ultra Short Laser Pulses." Doctoral thesis, KTH, Production Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3321.
Full textUEHARA, Takuya, Takato TAMAI, and Nobutada OHNO. "Molecular Dynamics Simulations of Shape-Memory Behavior Based on Martensite Transformation and Shear Deformation." The Japan Society of Mechanical Engineers, 2006. http://hdl.handle.net/2237/9014.
Full textWang, Zhiyi S. M. Massachusetts Institute of Technology. "Computational framework for simulating the deformation and fracture response of oligocrystalline shape memory alloys." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120442.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 89-94).
Shape memory alloys (SMAs) are a class of metallic materials that can recover their original shapes when heated above a certain temperature. Unique features including the superelasticity and shape memory effect have made SMAs attractive materials for a variety of fields ranging from bioengineering to aerospace engineering. In polycrystalline forms, the desirable properties of SMAs have been significantly limited by severe premature intergranular fractures at grain boundaries. Chen et al. (2009) showed that the intergranular fracture in Cu-based SMAs can be mitigated in fine wire forms with bamboo-shaped oligocrystalline microstructure. Tensile tests conducted in the oligocrystalline systems show that large ductility limits approaching those of a single crystal can be achieved while avoiding the issues involved in single crystal processing. It is, thus, of great importance to investigate how the microstructure and grain boundary characteristics affect phase transformation of oSMAs and how to delay transformation-induced fractures. In this thesis, an anisotropic single-crystal constitutive model is developed to study the underlying mechanism of transformation-induced fracture in oSMAs from a numerical perspective at the microstructural level. The model is based on the micromechanical constitutive framework by Thamburaja and Anand (2001) and a robust explicit integration scheme is developed to update the constitutive law. In order to investigate the effects the grain boundary characteristics have on the martensitic phase transformation and transformation-induced fracture, finite element simulations are performed for modeling the stress-strain response and martensite-austenite phase transformation under uniaxial tension loading condition for oSMA wires with triple junction structures. A quantitative analysis of the simulation results is conducted at the microstructural level in each transformation system to interpret the initiation of transformation-induced fracture. The simulations provide insights on the mechanical response, energy absorption of oSMA wires, as well as shed light on the microstructural design objectives of oSMA to avoid or delay the intergranular fracture.
by Zhiyi Wang.
S.M.
Giacalone, Giuliano. "A matter of shape : seeing the deformation of atomic nuclei at high-energy colliders." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASP072.
Full textCollider experiments conducted atthe BNL RHIC and at the CERN LHC show thatthe the emission of particles following the interactionof two nuclei at relativistic energy is highlyanisotropic in azimuthal angle. This observationis compatible with a hydrodynamic paradigm, accordingto which the final-state hadrons are emittedfollowing the expansion of a fluidlike systemcreated in the interaction region. Withinthis paradigm, anisotropy in the emission of particlesis enhanced whenever the colliding nucleihave deformed ground states. By meansof high-quality comparisons between the predictionsof hydrodynamic models and particle colliderdata, I study the phenomenological manifestationsof the quadrupole deformation of atomicnuclei in relativistic ¹⁹⁷Au+¹⁹⁷Au, ²³⁸U+²³⁸U,and ¹²⁹Xe+¹²⁹Xe collisions. This analysis demonstratesthat a deep understanding of the structureof the colliding ions is required for the interpretationof data in high-energy experiments. RHICdata confirms in particular the well-known factthat the geometry of ²³⁸U nuclei is that of a welldeformedellipsoid, while indicating that ¹⁹⁷Au nuclei are nearly spherical, a result which is atodds with the estimates of mean-field and empiricalnuclear models. LHC data brings instead evidenceof quadrupole deformation in the groundstate of ¹²⁹Xe nuclei, ascribable to the first visiblemanifestation of shape coexistence phenomena inhigh-energy nuclear experiments. I introduce asimple method to isolate collision configurationsthat maximally break azimuthal symmetry dueto the orientation of the deformed nuclei. Thisallows me to define observables with an unprecedentedsensitivity to the deformation of the collidingspecies, thus paving the way for quantitativestudies of nuclear structure at high energy
Debora, Monego. "Effect of Surface Ligands on Colloidal Stability, Shape and Sedimentation of Apolar Nanoparticles." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23288.
Full textZhang, Baozhuo. "Synchrotron Radiation X-Ray Diffraction of Nickel-Titanium Shape Memory Alloy Wires During Mechanical Deformation." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc848138/.
Full textBenafan, Othmane. "Deformation and Phase Transformation Processes in Polycrystalline NiTi and NiTiHf High Temperature Shape Memory Alloys." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5123.
Full textPh.D.
Doctorate
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering
Hradil, Jiří. "Adaptive parameterization for Aerodynamic Shape Optimization in Aeronautical Applications." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234267.
Full textYu, Hao. "Modeling of High Strain Rate Compression of Austenitic Shape Memory Alloys." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062835/.
Full textDonoghue, Jack. "Hybrid additive manufacture and deformation processing for large scale near-net shape manufacture of titanium aerospace components." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/hybrid-additive-manufacture-and-deformation-processing-for-large-scale-nearnet-shape-manufacture-of-titanium-aerospace-components(5bb9e7db-824e-46e2-a832-c2780e15d6b8).html.
Full textVeelo, Bastiaan Niels. "Variations of Shape in Industrial Geometric Models." Doctoral thesis, Norwegian University of Science and Technology, Department of Product Design, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-240.
Full textThis thesis presents an approach to free-form surface manipulations, which conceptually improves an existing CAD system that constructs surfaces by smoothly interpolating a network of intersecting curves. There are no regularity requirements on the network, which already yields superior modelling capabilities compared to systems that are based on industry-standard NURBS surfaces.
Originally, the shape of such a surface can be modified only locally by manipulating a curve in the network. In this process there is an inherent danger that the curve is being pulled away from intersections that it has with other curves. When this happens, the network is invalidated as a surface representation, and many curves may have to be adjusted to restore network consistency and surface quality. This thesis contributes a method that solves these problems by propagating changes that are made in one curve to curves in its vicinity. How and to what extent curves react to changes is controlled by two parameters that can be varied along the curve that is being manipulated. Any curve may be constrained in one or more degrees of freedom. The integrity of the curve network is implicitly conserved, as well as the geometric continuity of the surface.
The result is a tool for the modification of curve-interpolating surfaces, which can easily be applied to large areas on models with any level of detail. This allows designers to concentrate on the creative process, rather than on planning chains of actions. They can explore different design variations, optimise shapes further, and generally be more productive.
Dette doktorgradsarbeidet presenterer en fremgangsmåte for formgivning og modifisering av datamaskinbaserte, skulpturerte flater. Metoden forbedrer et eksisterende system for data-assistert konstruksjon (DAK) som bygger dobbeltkrummede flater ved å interpolere et nettverk av skjærende kurver. Nettverket trenger ikke være regelmessig, noe som allerede gir bedre modelleringsmuligheter sammenliknet med systemer som er basert på standard NURBS flater.
En slik flate kan opprinnelig bare endres lokalt ved å dra i en kurve. I denne prosessen er det fare for at kurven blir dratt fra skjæringspunkter den har med andre kurver. Hvis dette skjer, representerer ikke nettverket en flate lenger, og mange kurver må justeres for å få tilbake integriteten i nettverket og kvaliteten i formen. Denne avhandlingen bidrar med en metode som løser disse problemene ved å spre endringer som blir gjort i en kurve til andre kurver i nærheten. Hvordan og i hvilken utstrekning kurvene reagerer på endringen styres av to parametre som kan varieres langs kurven som blir endret. Enhver kurve kan låses i en eller flere frihetsgrader. Integriteten til nettverket samt glattheten i formen blir bevart automatisk.
Resultatet er et redskap for modifikasjon av kurve-interpolerende flater som med letthet kan brukes på større områder av modeller med hvilken som helst grad av detalj. Dette gir designere muligheten til å konsentrere seg om det kreative, istedenfor å planlegge handlingsrekker. De kan utforske forskjellige designvariasjoner, optimalisere former ytterligere, og i det hele tatt være mer produktive.
Blenkinsopp, Robert. "A method for measuring human foot shape during running stance." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/16907.
Full textRose, Kelly Kathleen. "Identification of Fold Hinge Migration in Natural Deformation: A New Technique Using Grain Shape Fabric Analysis." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/43205.
Full textMaster of Science
Casalena, Lee. "Multimodal Nanoscale Characterization of Transformation and Deformation Mechanisms in Several Nickel Titanium Based Shape Memory Alloys." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1499568013015563.
Full textKrishnan, Vinu Bala. "Low temperature NiTiFe shape memory alloys actuator engineering and investigation of deformation mechanisms using in situ neutron diffraction at Los Alamos National Laboratory /." Orlando, Fla. : University of Central Florida, 2007. http://purl.fcla.edu/fcla/etd/CFE0001934.
Full textKrishnan, Vinu. "LOW TEMPERATURE NITIFE SHAPE MEMORY ALLOYS: ACTUATOR ENGINEERING AND INVESTIGATION OF DEFORMATION MECHANISMS USING IN SITU NEUTR." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3373.
Full textPh.D.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Materials Science & Engr PhD
Mahoi, Salie. "Influence of shape of solid explosives on the deformation of circular steel plates : experimental and numerical investigations." Doctoral thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/5514.
Full textGervais, Olivier. "Effects of Long-Term Selection for Non-Destructive Deformation in White Leghorns." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217200.
Full textLundgren, Paulina, and Husein Mohammed Harbe. "Model correlation of an articulated hauler frame." Thesis, Linnaeus University, School of Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-6376.
Full textThis master thesis has been carried out on behalf of Volvo Construction Equipment. A front frame of an
articulated hauler should be analysed according to the Finite Element Method and vibration tests should be
made. The results from the experimental tests should be correlated with the analytical test results here using
MAC-values. These values will show if the FE-model represents the physical structure correctly.
Visualisations are made on both the experimental and analytical results to get a better understanding about the
eigenmodes of the frame.
The final results showed that the FE-model was not a match to the physical structure which the experimental
tests were made on. It should be noted that the final result only states the present situation. The CAD-model had
not been completed when this thesis was performed and therefore some deviation occurred in the results. Some
actions are needed in order to reach a better result and they are stated in this report. When they are made, the
results can be improved by following the work that has been done in this master thesis.
AZEGAMI, Hideyuki, Takahiro IWAI, 秀幸 畔上, and 孝広 岩井. "大変形を考慮した接触する弾性体の形状同定." 一般社団法人日本機械学会, 2008. http://hdl.handle.net/2237/21119.
Full textZhang, Xiaoliu. "MRI-based active shape model of the human proximal femur using fiducial and secondary landmarks and its validation." Thesis, University of Iowa, 2018. https://ir.uiowa.edu/etd/6349.
Full textSrivastava, Vikas. "A large-deformation thermo-mechanically coupled elastic-viscoplastic theory for amorphous polymers : modeling of micro-scale forming and the shape memory phenomenon." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57787.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 185-193).
Amorphous polymers are important engineering materials; however, their nonlinear, strongly temperature- and rate-dependent elastic-viscoplastic behavior is still not very well understood, and is modeled by existing constitutive theories with varying degrees of success. There is no generally agreed upon theory to model the large-deformation, thermo-mechanically coupled response of these materials in a temperature range which spans their glass transition temperature. Such a theory is crucial for the development of a numerical capability for the simulation and design of important polymer processing operations, and also for predicting the relationship between processing methods and the subsequent mechanical properties of polymeric products. We have developed a large-deformation thermo-mechanically coupled elastic-viscoplastic theory for thermoplastic amorphous polymers and shape memory polymers which spans their glass transition temperature. The theory has been specialized to represent the major features of the thermo-mechanical response of three technologically important thermoplastic amorphous polymers - a cyclo-olefin polymer (Zeonex-690R), polycarbonate, poly(methyl methacrylate) and a representative thermoset shape memory polymer - in a temperature range from room temperature to approximately 40 C above the glass transition temperature of each material, in a strain-rate range of ~ 10-4 to 101 s-1, and compressive true strains exceeding 100%. Our theory has been implemented in the finite element program ABAQUS. In order to validate the predictive capability of our constitutive theory, we have performed a variety of macro- and micro-scale validation experiments involving complex inhomogeneous deformations and thermal processing cycles. By comparing some key features, such as the experimentally-measured deformed shapes and the load-displacement curves from various validation experiments against corresponding results from numerical simulations, we show that our theory is capable of reasonably accurately reproducing the results obtained in the validation experiments.
by Vikas Srivastava.
Ph.D.