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1
Ruan, Haihui. "Collision between two perfectly plastic beam structures : modeling and verification /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?MECH%202004%20RUAN.
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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 235-241). Also available in electronic version. Access restricted to campus users.
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Cropper, Andrew Boyd. "The failure mode analysis of plastic gears." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.564396.
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This thesis presents the work conducted under the auspices of the Brite EuRam funded project, "PROGEAR" (contract number BRPR-CT98-0703), which sought to better understand the failure modes of injection moulded plastic gears, such that their performance and reliability could be improved. In so doing, the work built upon previous research conducted at the Power Transmission Laboratory, at the University of Birmingham. This research utilised a range of materials including plain polymers and polymer composites, as well a wide variety of gear geometries. In addition, the type of testing that was carried out varied from dry running to oil-lubricated tests, using sophisticated, state-of-the-art equipment Five research areas were covered, and these were as follows: 1. The consolidation of existing knowledge in all aspects of injection moulded plastic gears, resulting in an extensive literature review. 2. The investigation of the dry-running wear resistance of plastic gears. 3. The investigation of the effects of oil-lubrication on the performance of plastic gears, includingt heir wear resistancea nd fatigues trength. 4. The investigation of the efficiency of plastic gears under dry-running, greaselubricated and oil-lubricated conditions. 5. The investigation of Pitch Line Fracture, which is a failure mode unique to dryrunning gears of specific polymeric materials. This thesis represents a significant contribution to the understanding of plastic gears, and should enable significant improvements in the power density, durability and wear resistance in future designs of plastic gears. This research also maps out important avenues for future research.
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Opitz, Andrea. "Stereo plastic calibration, simulation and data analysis /." [S.l.] : [s.n.], 2007. http://www.zb.unibe.ch/download/eldiss/07opitz_a.pdf.
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Weaver, J. M. R. "The ultrasonic imaging of plastic deformation." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375316.
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Vaziri, Reza. "Finite deflection dynamic analysis of rigid-plastic beams." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25142.
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An analytical procedure, which retains the influence of finite deflections,
is developed herein for the dynamic behaviour of rectangular shaped rigid-plastic beams. In the general formulation of the problem deformation is assumed to proceed under two distinct mechanisms depending on the extent to which the value of the peak pressure exceeds the static collapse pressure of the beam. These mechanisms are described by kinernatically admissible velocity fields that satisfy the appropriate continuity conditions. The governing equations of motion are derived from a variational
statement consisting of the principle of virtual work and D'Alembert's principle. The conventional parabolic yield surface (which describes the coupling action between axial forces and bending moments at yield) and its associated flow rule are adopted to describe the plastic behaviour of the beam material. The kinematic small but finite deflection analysis, in which the membrane forces and bending moments interact, generally leads to basic equations which are of nonlinear character. These resulting equations
are solved analytically and closed form expressions are developed for the prediction of maximum permanent deformation of the beam. A dynamic membrane analysis is carried out in those cases when the input energy is sufficiently high that the beam undergoes moderately large deformation (i.e. deflections of the order of beam thickness). Finally the dependence of the permanent deflection on the applied pressure and impulse is obtained for a family of rectangular pulses. This relationship is represented by an isoresponse curve in a form convenient for direct engineering use.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Mohamed, Salah-Eldin A. "Elastic-plastic instability of plane frames." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/12092.
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鄭榕明 and Yung-ming Cheng. "Large strain elasto-plastic soil-structure interaction analysis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1992. http://hub.hku.hk/bib/B31232528.
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HECKE, MILDRED BALLIN. "POTENTIAL WIDESPREAD AND OPTIMIZATION IN ELASTIC-PLASTIC ANALYSIS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1991. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33252@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOREste trabalho focaliza a análise elasto-plástica de componentes mecânicos e estruturais. Especial atenção é dada a formulação da equação constitutiva. A relação constitutiva em taxas é equacionada na forma de potenciais generalizados onde utiliza-se o conceito de subgradientes. Para tal, são introduzidos conceitos básicos da termodinâmica sendo usadas variáveis internas para descrever os mecanismos dissipativos. São apresentados pseudo-potenciais em incrementos finitos de tensões e deformações que incorporam a admissibilidade plástica e são capazes de descrever o descarregamento elástico local desde que não haja plastificação seguida de descarregamento no passo. Esta forma é utilizada na obtenção-de Princípios de Mínimo para a análise elasto-plástica. A discretização espacial é feita utilizando o Método dos Elementos Finitos. São considerados algoritmos para a solução de tal problema. São incluídas aplicações numéricas a problemas planos e a flexão de placas.
The elastic-plastic analysis of structural components is considered. The formulation of the constitutive equations is specially focused. The constitutive relation for rates is derived from pseudo-potentials by using the sub-gradient concept. Internal variables are introduced to describe dissipation mechanisms and thermodynamical concepts are used in order, to obtain the corresponding potential relationships. Generalized potentials are also presented for the approximate constitutive relation in terms of finite increments of strain and stress. This formulation incorporate plastic admissibility constraínts and it is also able to describe local elastic unloading except the case when it follows plastic yielding in the true incremental process. This form of the constitutive equation is used next to obtain minimum principles for the elastic-plastic analysis. Spatial discretization is performed by means of the Finíte Element Method. Some algorithms are discussed for the solution of the variational formulations considered. Numerical applications are presented for plane problems and plate bending.
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Nanda, Atul. "Finite element analysis of elastic-plastic anisotropic soils." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/53650.
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Elastic-plastic stress·strain models are developed for initially anisotropic soils. The models are developed for both total stress (undrained) analyses and for effective stress (drained) analyses. For anlsotroplc undralned coheslve soils under monotonic loading an elastic-plastic isotropic-hardening model is developed. For complex loading conditions the model is extended using multisurface plasticity. For effective stress analyses of soils, the Cam-Clay model concepts are generalized for initially anisotropic soils. Both isotropic and anisotropic hardening are used in the model. The behavior of the models is investigated under several loading conditions and some comparisons are made with experimental triaxial data. A nonlinear three-dimensional finite element program is developed in which the models are implemented. An updated Lagrangian large displacement analysis is also included. The constitutive models developed are used to investigate the influence of initial anisotropy on the bearing capacity, deformation and pore pressure development under footings in both plane-strain and three dimensional conditions. It is found that for the range of anisotropy encountered in the field, the deformation and bearing capacity are significantly different.Ph. D.
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Cheng, Yung-ming. "Large strain elasto-plastic soil-structure interaction analysis /." Hong Kong : University of Hong Kong, 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13212758.
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Howell, Geoffrey Peter. "Identification of plastic strain using thermoelastic stress analysis." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/412636/.
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Identification of regions containing plastic strain arising from the welding process is performed through the application of thermoelastic stress analysis (TSA) and finite element (FE) modelling. An approach is developed that removes the requirement to have a physical reference specimen for the component studied by developing a 'synthetic reference bitmap' using finite element analysis. The regions containing plastic strain can be identified with TSA by collecting data from a 'reference' plastic strain free specimen from the TSA data and creating a resultant bitmap. Here, a synthetic bitmap is developed that mimics the thermoelastic response of a physical reference specimen. The approach is validated against physical reference specimens of different geometries and materials (AL2024 and 316L stainless steel) and is shown to accurately model the thermoelastic response. The newly developed synthetic bit map approach is applied to specimens containing welds and it is shown that the regions that contain plastic strain in the heat affected zone (HAZ) of a double bead welded 316L stainless steel specimen can be revealed. The predicted changes in thermoelastic response are compared to plastic strain predictions generated by thermomechanical modelling of the welded specimen and the distribution of plastic strain found by the TSA matches that given by the model. The relationship between the change in thermoelastic response and plastic strain has been investigated and the results suggest there is a change in the thermoelastic response as a result of plastic straining. However, uncertainties in the data resulting from detector noise and other errors mean that further development of the experiments and the equipment is required to provide a conclusive and quantitative relationship. It has also been demonstrated that TSA can be used outside of the laboratory in onsite trials in two coal fired power stations. Thermoelastic data was successfully recorded from pipe welds in-situ. To achieve this a new means of loading the pipes was devised based on vibration excitation, and the difficulties of performing surface measurements on heavily corroded pipes were overcome. The results from the onsite tests show that TSA can be used as an in-situ assessment technique and that is no longer restricted to being a laboratory based technique.
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Zubillaga-Pow, Jun. "Plastic resistance : a psychopolitical analysis of Beethoven historiography." Thesis, King's College London (University of London), 2015. https://kclpure.kcl.ac.uk/portal/en/theses/plastic-resistance(205a68b6-7699-4447-806e-7ca027d71aa7).html.
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Based on historical and musicological texts and acts from the nineteenth to twenty-first century, this thesis proposes the concept of plastic resistance as an epistemological method to analyse the psychical and political perceptions of Beethoven’s life and music. Relying on the philosophy of Fichte and Lacan, I contend that the psychopolitics of this reception/resistance history is predicated critically on the musicians’ and listeners’ ability and affect to posit musical semantics unconsciously. I further argue that, during the negotiation of mastery, autonomy and subjectivity, the musical acts of composing, analysing and performing are influenced by psychical and political aesthetics. These affective resistances are buttressed by the psychoanalytical structures of neurosis, psychosis and perversion. The thesis is divided into five chapters with the first two chapters setting the historical and theoretical backgrounds to various subjective actions and reactions that have created or destroyed musical meaning. The rest of the thesis place specific focus on more recent approaches to Beethoven’s piano sonatas and string quartets, as well as the plastic properties of their material resistance. In the first chapter, I trace a macrohistory of Beethoven reception in Western Europe and the United States from the nineteenth century to the present day. After an explication of the theoretical constitutions of the psychical resistance and the musical unconscious, I apply the ideas of inclusive and extractive resistances to show how the different attitudes towards Beethoven’s music result in creative and destructive institutions of musical hermeneutics. I reinforce the thesis of plastic resistance in the subsequent three chapters. First, the act of notation as embodied in sketch processes traverses the imaginary, fantasmatic and hysterical phases, but only a mode of critical mastery can direct listeners towards sound musical knowledge. Second, the dialectical nature of musical meaning readily predetermines the psychotic capacity of the analytic act; analysts arguably become occupied with negotiating their semantic uncertainty with chance operations. Finally, musicians embody a form of performative perversion by externalising their plastic intimacy through affective gestures and subjective speech acts during rehearsals, interpretations, and performances. In conclusion, plastic resistance has exerted a significant psychopolitical force and transformed the epistemologies of Beethoven historiography.
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Wan, Deborah Jo-May 1974. "On elastic-plastic large deformation analysis of beams." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/10076.
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Ball, Ryan. "Experimental analysis of composite reinforced concrete beams." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1177002341.
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Leinster, James Carson. "The design of steel frames using plastic theory." Thesis, Queen's University Belfast, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277487.
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Kihlander, Jesper. "Finite Element simulation of vibrating plastic components." Thesis, Linköpings universitet, Hållfasthetslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-89984.
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For automotive plastic parts there is a clear demand on an increased quality of the FE models. This demand is related to the increased use of simulations, both due to a reduced number of prototypes and an increased number of load cases. There have been studies showing a change of dynamic properties in injection molded components. The conclusion from these studies are that the change depends on residual stresses built in during the injection process. This study use simple models to try to get a working method and from the results find out the basic relations between residual stresses and dynamic properties. A method was developed and the results showed that the residuals had a major impact on the dynamic properties. Continuation on this work would be to use more complex models, to try to mimic results from reference studies and tests.
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Bjerkli, Camilla Louise. "The cycle of plastic waste : An analysis on the informal plastic recovery system in Addis Ababa, Ethiopia." Thesis, Norwegian University of Science and Technology, Industrial Ecology Programme, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1410.
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This study deals with the informal plastic recovery system in Addis Ababa. The purpose of this thesis is to explore the organization and the actors involved in the system. Further, the thesis attempts to estimate the size of the informal sector, the amount of materials collected, the quality of the materials, and the economic aspects of the activities. This is followed by a discussion on the strengths and the barriers that the system faces today. In order to gain a holistic overview of the plastic recovery system, the formal solid waste management system and the private sector involvement in solid waste are described since they form an integral part of the system.
Structuration theory and an actor-oriented approach have been used, based on the interaction between the structures and the actors within the system, in order to explain why actors within the system act in the way that they do and why the system has developed in the way it has. Since this thesis is the first study on the informal plastic recovery system in Addis Ababa, the data used is mainly primary data collected during the fieldwork. Both qualitative and quantitative methodologies were used to gain a broader understanding of the system and the activities involved, and to increase the validity of the data.
This study has shown that thousands of individuals in Addis Ababa are dependent on the recovery of plastic materials in order to make a living. Moreover, the activities have showed to be economically profitable and to play an important role in solid waste management. It is argued that a lack of a formal system for the recovery of plastic materials has made it possible for the informal sector to fill the gap that the government does not fill. Further, the government’s lack of awareness of the informal sector has made it possible for the recovery system to develop without interference. The governmental ignorance of the informal plastic recovery system as well as civil society’s lack of trust and creditability in the government has proven to be one of the main difficulties confronting the plastic recovery system. Because of this, every attempt from the governmental side to implement new strategies within the system seems to fail, since they do not consider or consult the decisions with actors involved at the local level. The thesis highlights that it is essential that the government starts to recognize the informal sector and tries to gain their trust and credibility in order to improve the overall solid waste management system in Addis Ababa.
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Schubak, Robert Brian. "Nonlinear rigid-plastic analysis of stiffened plates under blast loads." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/31482.
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The large ductile deformation response of stiffened plates subjected to blast loads is investigated and simplified methods of analysis of such response are developed. Simplification
is derived from modelling stiffened plates as singly symmetric beams or as grillages thereof. These beams are further assumed to behave in a rigid, perfectly plastic manner and to have piecewise linear bending moment-axial force capacity interaction relations, otherwise known as yield curves.
A blast loaded, one-way stiffened plate is modelled as a singly symmetric beam comprised
of one stiffener and its tributary plating, and subjected to a uniformly distributed line load. For a stiffened plate having edges fully restrained against rotations and translations,
both transverse and in-plane, use of the piecewise linear yield curve divides the response of the beam model into two distinct phases: an initial small displacement phase wherein the beam responds as a plastic hinge mechanism, and a final large displacement phase wherein the beam responds as a plastic string. If the line load is restricted to be a blast-type pulse, such response is governed by linear differential equations and so may be solved in closed form. Examples of a one-way stiffened plate subjected to various blast-type pulses demonstrate good agreement between the present rigid-plastic formulation and elastic-plastic beam finite element and finite strip solutions.
The response of a one-way stiffened plate is alternatively analysed by approximating it as a sequence of instantaneous mode responses. An instantaneous mode is analogous to a normal mode of linear vibration, but because of system nonlinearity exists for only the instant and deformed configuration considered. The instantaneous mode shapes are
determined by an extremum principle which maximizes the rate of change of the stiffened plate's kinetic energy. This approximate rigid-plastic response is not solved in closed form but rather by a semi-analytical time-stepping algorithm. Instantaneous mode solutions compare very well with the closed-form results.
The instantaneous mode analysis is extended to the case of two-way stiffened plates, which are modelled by grillages of singly symmetric beams. For two examples of blast loaded two-way stiffened plates, instantaneous mode solutions are compared to results from super finite element analyses. In one of these examples the comparison between analyses is extremely good; in the other, although the magnitudes of displacement response
differ between the analyses, the predicted durations and mechanisms of response are in agreement.
Incomplete fixity of a stiffened plate's edges is accounted for in the beam and grillage models by way of rigid-plastic links connecting the beams to their rigid supports. Like the beams, these links are assumed to have piecewise linear yield curves, but with reduced bending moment and axial force capacities. The instantaneous mode solution is modified accordingly, and its results again compare well with those of beam finite element analyses.
Modifications to the closed-form and instantaneous mode solutions to account for strain rate sensitivity of the panel material are presented. In the closed-form solution, such modification takes the form of an effective dynamic yield stress to be used throughout the rigid-plastic analysis. In the time-stepping instantaneous mode solution, a dynamic yield stress is calculated at each time step and used within that time step only. With these modifications in place, the responses of rate-sensitive one-way stiffened plates predicted by the present analyses once again compare well with finite element and finite strip solutions.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Piscia, Davide. "Analysis of night-time climate in plastic-covered grenhouses." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/123772.
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Este trabajo analiza el clima nocturno del invernadero. EL objeto del estudio es el invernadero de plástico sin calefacción, cuyo clima se estudia utilizando modelos CFD, modelos basados en los balance de energía (ES) y s datos experimentales. El fin es doble, por un lado se trata de analizar y comprender el clima nocturno del invernadero, y proponer soluciones a los problemas relacionados con las altas tasas de humedad. Por otro lado se investigan nuevos métodos de simulación del clima del invernadero, métodos basados en el uso conjunto o acoplamiento de modelos CFD y ES , y también basados en la técnica de optimización.
El Capitulo 1 introduce el contexto general y los objetivos que plantea el trabajo. El Capitulo 2 estudia el clima nocturno en un invernadero de capa sencilla. Para ello desarrolla un modelo CFD que incluye una UDF (User Define Function) para calcular la tasa de condensación. Una vez validado el modelo se analiza el comportamiento del invernadero bajo distintas condiciones de contorno.. El Capitulo 3 analiza una solución para combatir las bajas temperaturas nocturnas, la pantalla térmica. Los efectos de la pantalla se analizan mediante el uso del CFD. Se lleva a cabo una comparación completa entre el invernadero de capa sencilla y el invernadero con pantalla. El capitulo proporciona información detallada sobre el clima del invernadero y presenta un estudio paramétrico del efecto de la temperatura equivalente del cielo y la cesión de calor desde el suelo en el clima del invernadero con pantalla térmica. EL Capitulo 4 presenta un nuevo método para optimizar el diseño del invernadero. El método se basa en el acoplamiento de dos algoritmos de optimización que operan con el modelo ES. A su vez el modelo ES está conectado con el modelo CFD. El objetivo es doble, por un lado introducir una nueva manera de optimizar el diseño del invernadero, y por el otro lado tratar de resolver uno de los problemas evidenciados en el capítulo 2. El resultado muestra que un material de cubierta de alto poder de reflexión del infrarrojo lejano aportaría mejorías relevantes al clima del invernadero. El Capitulo 5 presenta un modelo acoplado para el estudio del clima del invernadero. EL CFD se utiliza para proporcionar las tasas de ventilación y los coeficientes convectivos al modelo ES. Esta técnica se utiliza para estudiar los efectos de diferentes estrategias de ventilación sobre el régimen de humedad con diferentes condiciones externas. Finalmente, el Capitulo 6 resume las conclusiones y propone algunos temas para futuras investigacionesThis work studied night-time greenhouse climate. The focus was on unheated plastic greenhouses and analyses were carried out using CFD models, Energy balance (ES) models and experimental data. The aims were twofold: on the one hand, it was intended to analyse and understand night-time greenhouse climate and propose solutions to the high-humidity issue. On the other hand, the aim was to investigate novel simulation approaches based on the coupling of CFD and ES models as well as the use of optimisation algorithms to study greenhouse climate. Chapter 1 is an introductory chapter which includes the general context and overall research objectives. Chapter 2 studies night-time climate in single-layer greenhouses by means of CFD. The model is validated and condensation User Defined Function (UDF) is introduced which accounted for the condensation rate found on the inner face of the greenhouse cover. Chapter 3 studies a commonly used solution to the issue of low night-time temperature. A thermal screen was analysed by means of CFD simulations. A thorough comparison was made between single-layer and screened greenhouses and detailed information was provided in order to build a framework for taking decisions as to whether to use a screen or not. Chapter 4 introduces a novel approach to optimizing greenhouse design; the approach relies on two optimization algorithms linked to an ES model which was coupled to a CFD model. The aim of the study was twofold: on the one hand to introduce a method offering a general approach for optimizing greenhouse design and on the other, to attempt to solve one of the issues highlighted in Chapter 2. It was shown that using a highly reflective covering material would have a theoretically significant impact on greenhouse performance. Chapter 5 introduces a coupled model for studying greenhouse climate. The CFD was used to provide the ventilation rate and convective coefficients for the ES model. This approach was applied to study the effects of different ventilation strategies on humidity under different outside air conditions. Finally Chapter 6 summarizes the conclusions and proposes themes for future research.
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Hamilton, Jordan David. "Fabrication and analysis of injection molded plastic microneedle arrays." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39481.
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This thesis describes the fabrication of plastic microneedle devices, their fabrication by injection molding, and analysis of the penetration mechanics. Injection molding is an economical mass-production technique that may encourage widespread adoption of microneedles for drug delivery.
Four polymers were injection molded into hexagonal and square patterns of between 91 and 100 needles per array. The patterns and geometries were chosen to study the effect of needle spacing and array design on penetration force. Two needle spacings of approximately 1 mm and 1.5 mm were employed for both patterns. Molded parts showed tip radii below 15 microns, heights of 600 to 750 microns, and an included angle of approximately 30 degrees.
An economic analysis performed of the injection molded polymer devices showed that they can be manufactured for approximately $0.10 - $0.179 per part, which should be low enough to gain market acceptance. The added benefits of low pain perception, improved drug delivery for certain treatments, and the possibly of being recyclable make
injection molded micro-needle devices a desirable alternative to silicon or metal microneedles.
Penetration tests were performed with plastic micro-needle arrays and arrays of steel needles of the same spacings and patterns. Silicone rubber with mechanical properties similar to human skin was used as a skin simulant. The results showed that the micro-needles penetrated skin to depths between 120 and 185 microns depending on
pattern, spacing, tip radius and needle length. This depth is sufficient to deliver drug therapies, but not so far that they stimulate the nerve endings present beyond 130 microns inside the dermis layer in human skin.
An analytical model was developed to estimate the effects of various microneedle and skin characteristics on penetration force. The model was based on literature sources and derived from test results. The model accounted for coefficient of friction, tip radius, tip angle, and needle spacing, as well as the skin mimic's mechanical properties such as elastic modulus, mode I fracture toughness, and puncture fracture toughness. A Monte Carlo simulation technique was used to correct for errors in needle length and testing angle. Comparison of the experiments to the model showed good agreement.
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Yalcin, Serhat. "Analysis And Modeling Of Plastic Wrinkling In Deep Drawing." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612485/index.pdf.
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Deep drawing operations are crucial for metal forming operations and manufacturing. Obtaining a defect free final product with the desired mechanical properties is very important for fulfilling the customer expectations and market competitions. Wrinkling is one of the fatal and most frequent defects that must be prevented. This study focuses on understanding the phenomenon of wrinkling and probable precautions that can be applied. In this study, dynamic &ndashexplicit commercial finite element code is used to simulate deep drawing process. The numerical experiments are compared with NUMISHEET benchmarks in order to verify the reliability of the finite element code and analysis parameters. In order to understand plastic wrinkling, the effect of blank holder force is investigated. Axisymmetrical numerical models of a cup are investigated with different blank holder forces. Wrinkling instability is illustrated in energy diagrams of the process. Effect of anisotropy on wrinkling is also discussed by comparing isotropic and anisotropic numerical experiments with the material as steel. Different drawbead models, both equivalent and physical, are implied to the problem and results are discussed. Besides numerical analysis, experimental verification is also conducted as conventional deep drawing operation by a hydraulic press. This yields to the ability to understand the effect of blank thickness on wrinkling formation through numerical and experimental analyses. The wave formations of different sized blanks with four different thicknesses are illustrated.
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Elvidge, M. "The plastic analysis of pitched roof steel portal frames." Thesis, University of Bradford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374916.
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Kim, Do-Nyun. "Contributions to the anisotropic elasto-plastic analysis of shells." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/49760.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 133-142).
Shells are probably the most widely used structural component in engineering and also in nature due to their high efficiency and excellent performance when properly designed. On the other hand, they can be very sensitive to changes in geometries, thicknesses, applied loads and boundary conditions. Hence much research effort has been devoted to the reliable and efficient analysis of shells. This work contributes to the anisotropic elasto-plastic analysis of shells by addressing key issues in developing shell elements for finite element analysis and an elasto-plasticity model considering anisotropy and its evolution. First we develop a shell element that models the three-dimensional (3D) effects of surface tractions. The element is the widely used MITC4 shell element enriched by the use of a fully 3D stress-strain description, appropriate through-the-thickness displacements to model surface tractions, and pressure degrees of freedom for incompressible analyses. The element formulation avoids instabilities and ill-conditioning. We also develop a triangular 6-node shell element that represents an important improvement over a recently published element. The element is spatially isotropic, passes the membrane and bending patch tests, contains no spurious zero energy mode, and is formulated without an artificial constant. In particular, the improved element does not show the instability sometimes observed with the earlier published element.
(cont.) Finally we review a constitutive model for anisotropic elasto-plastic analysis which takes into account the anisotropy of both the elastic and plastic material behaviors, as well as their evolution with plastic strains. It is based on continuum energy considerations, the Lee decomposition of deformations and a stored energy function of the logarithmic strains. The present work focuses on giving some physical insight into the parameters of the model and their effects on the predictions in proportional and in non-proportional loading conditions.
by Do-Nyun Kim.
Ph.D.
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Nikolic, Marko. "Protection Structures of Glass Fiber Reinforced Plastic – Static Analysis." Thesis, KTH, Hållfasthetslära (Inst.), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103731.
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The oil- and gas industry has increasingly begun to switch from oil platforms and instead started to install the modules, process stations, etc. directly on the seabed. Some parts are more sensitive to external loads than others, and it is crucial to protect them to avoid damage on the structures and even gas/oil leakage. Protection covers made of glass fiber reinforced plastic (GRP) is becoming more frequently used in the offshore industry due to its low cost and good mechanical properties. Common load cases that the GRP cover could be exposed to have been identified and an investigation has been carried out to see what influence different factors like lay-up sequence and the number of plies has on the GRP cover. A fast and effective working method for future projects regarding GRP covers has been developed with the usage of Ansys and Excel. Analysis showed that for the installation and trawl net friction load cases the number of failed layers are very much dependent on the lay-up sequence of the GRP cover. Installation should be done vertically in order to prevent ply failure. For the trawl impact and Trawl Over-Pull load cases the numbers of failed plies are almost independent of the lay-up sequence. The conclusion is that lay-up sequences of [0/90]s and [-45/45]s are the most appropriate ones for this type of GRP cover and for the considered load cases. A total of 48 plies were recommended to ensure a completely intact protection structure for installation and trawl net friction, and only get small local failure at the trawl impact and over-pull load cases.
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Suh, Myung Sung. "Plastic analysis of dented tubes subjected to combined loading." Thesis, Massachusetts Institute of Technology, 1987. https://hdl.handle.net/1721.1/121910.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1988.Title as it appeared in M.I.T. Graduate List, June 1987: Plastic analysis of dented tubes under combined loading.
Bibliography: leaves 194-198.
by Myung Sung Suh.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1988.
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Brejchová, Ingrid. "Řízení rizik ve společnosti PLASTIC BOX CZ, s.r.o." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241320.
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This diploma thesis deals with risk management of a selected company. The described company is called PLASTIC BOX CZ, Ltd. and it is engaged in the manufacture of plastic products. The theoretical part contains the definition of components, which are mainly identification, analysis and methods to reduce individual risks. Appropriate analytical methods related to the risk management process are subsequently defined. In the analytical part, risks of the business entity are identified using selected methods. Risk analysis is performed by the FMEA analysis and elaborated in the specific process of running the company. The last part of this thesis includes the design of a risk management system of operating the company PLASTIC BOX CZ, Ltd., which is meant to ensure minimization and prevention of possible risks.
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Gondle, Raj Kumar. "Finite element analysis of long-term performance of buried high density polyethylene pipes." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4935.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains x, 122 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 116-122).
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Ibrahim, M. K. "Algorithms for spectrum estimation and detection of buried plastic pipes." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382869.
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Haliscelik, Murat. "Elastic-plastic Finite Element Analysis Of Semi-hot Forging Dies." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610542/index.pdf.
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Semi-hot or warm forging is an economical alternative to the conventional forging processes by combining advantages of hot and cold forging processes.
In this study, a new forging process sequence and design of the preform die for a part which has been produced by hot forging are proposed to be produced by semi-hot forging. Thermo-mechanical finite element analyses are performed over the stages of forging process. The billet and the dies are modeled as elastic-plastic bodies. Effects of preform die geometry on the die stresses and the forging load are investigated using finite element method. Comparison of the results obtained by using two different commercial finite element analysis programs is done for semi-hot and hot forging temperature ranges. The forging temperatures are determined for the particular part and the experiments are conducted by using the 1000 ton forging press. The parts are produced without any defects and material wastage in the form of flash is reduced. The numerical results are also compared with the experimental results and a good agreement is achieved.
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Ghasemi, Ghamsari Amir H. "Analysis of elastic and elasto-plastic behaviour of spatial structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/NQ34769.pdf.
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Liu, Xuegang. "Experimental and theoretical analysis of the buried corrugated plastic pipe." Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1175714554.
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CARDOSO, LUIZ ALBERTO LISBOA DA SILVA. "ANALYSIS OF PLASTIC NEURAL NETWORK MODELLING APPROACH TO SIGNAL PROCESSING." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1992. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9512@1.
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MARINHA DO BRASILOs modelos plásticos de redes neurais são estudados e avaliados como uma interessante abordagem da neurocomputação ao processamento de sinais. Dentre estes, o modelo SONN, recentemente proposto por Tenório e Lee, é revisado e adotado como base para a implementação de um ambiente interativo de prototipagem e análise de redes, dada sua reduzida carga heurística. Como ilustração de seu emprego, um problema de detecção e classificação de sinais pulsados é solucionado, com resultados que preliminarmente indicam a adequação do modelo como ferramenta na filtragem não-linear de sinais e no reconhecimento de padrões.
Plastic neural network models are evaluated as an attractive neurocomputing approach to signal processing. Among these, the SONN model, as recently introduced by Tenorio and Lee, is reviewed and adopted as the basis for the implementation of an interactive network prototyping and analysis system, due to its reduced heuristics. Its use is exemplified in the task of detection and classification of pulsed signals, showing up results that preliminarily qualify the model as a tool for non-linear filtering and pattern recognition applications.
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QUARESMA, DOUGLAS MIGLIANO. "A MODEL FOR ELASTO-PLASTIC ANALYSIS OF AXISYMMETRIC THIN SHELLS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1996. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19089@1.
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PETRÓLEO BRASILEIRO S. A.Neste trabalho a formulação do modelo de elementos finitos para cascas finas axissimétricas é estendida à análise numérica, incluindo os efeitos de não-linearidade do material, para a modelagem de fenômenos elasto-plásticos. O algoritmo utilizado emprega a solução incremental em um esquema explicito de integração com sub-incrementação da carga no processo iterativo de solução da equação de equilíbrio. Este esquema de integração da solução permite o controle do campo de estado de tensões mantendo a tensão equivalente no interior ou sobre a superfície de escoamento. Na implementação, o método de Newton Raphson, na forma modificada, é utilizado na solução do sistema de equações de equilíbrio resultante. A cinemática de deformação do modelo utilizado emprega apenas graus de liberdade de translação referidos à curva geratriz da superfície média da casca para representar as condições de compatibilidade geométrica da casca. Condições de contorno de continuidade e de fixação, referidas a rotação da normal à casca são impostas no modelo através do método de penalização. O desempenho do modelo proposto na análise não-linear elasto-plástica é avaliado através da comparação com outros resultados analíticos numéricos disponíveis na literatura e discutidas as características de convergência da solução no controle do erro numérico permitido entre duas iterações sucessivas.
In this work the formulation of a finite element axisymetric thin wall shell is extended to the numerical analisys including material nonlinear effects such as elasto-plastic phenomena. The algorithm employs the incremental solution scheme in an explicit integration with a load sub-incrementation in the procedure for equilibrium equation solution. This solution integration scheme allows restraining of stress state field with the equivalent stress withn or on the yielding surface. The modified Newton- Raphson method is used in the solution of resulting system of equilibrium equation. The kinematics of deformation employed in the model uses only translation degrees-of-freedom refered to the generatrix of the element midsurface to represent geometric compatibility conditions of the shell. Boudary conditions such as normal rotation fixity and coontinuity are imposed to the model through the penalty method. Some numerical analyses are presented to evalute the model capabilities in nonlinear elastoplastic examples, which results are compared to other numerical analytic solutions available in the literature. Solution convergebce, within controlling of the error allowed in the numerical solution, in discussed and evaluated.
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Yeung, Richard Ching King. "Rigid-plastic finite element analysis of static and dynamic collapse." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38201.
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Rizik, Vivian. "Analysis of an elasto-visco-plastic model describing dislocation dynamics." Thesis, Compiègne, 2019. http://www.theses.fr/2019COMP2505.
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Dans cette thèse on s'intéresse à l'analyse théorique et numérique de la dynamique des densités des dislocations, où les dislocations sont des défauts cristallins, apparaissant à l'échelle microscopique dans les alliages métalliques. En particulier, on considère en premier temps l'étude du modèle de Groma-Czikor-Zaiser (GCZ) et en second temps l'étude du modèle de Groma-Balog (GZ). Il s'agit en réalité d'un système d'équations de type paraboliques et de type Hamilton-Jacobi non-linéaires. Au départ, nous démontrons un résultat d'existence et d'unicité d'une solution régulière en utilisant le principe de comparaison et un argument de point fixe pour concernant le modèle GCZ. Ensuite, nous démontrons un résultat d'existence global en temps pour le modèle de GB, en se basant sur les notions des solutions de viscosités discontinues et sur une nouvelle estimation sur la variation totale de la solution, ainsi que sur la propagation à vitesse finie des équations régissantes. Ce résultat est étendu aussi au cas des systèmes d'équations d'Hamilton-Jacobi général. Enfin, nous proposons un schéma numérique semi-explicite permettant la discrétisation du modèle de GB. Nous montons, en s'appuyant sur l'étude théorique, que la solution discrète convergent vers la solution continue, ainsi qu'une estimation d'erreur entre la solution continue et la solution numérique. Des simulations montrant la robustesse du schème numériques sont également présentéesIn this thesis, we are interested in the theoretical and numerical analysis o the dynamics of dislocation densities, where dislocations are crystalline defects appearing at the microscopic scale in metallic alloys. Particularly, the study of the Groma-Czikor-Zaiser model (GCZ) and the study of the Groma-Balog model (GB) are considered. The first is actually a system of parabolic type equations, where as, the second is a system of non-linear Hamilton-Jacobi equations. Initially, we demonstrate an existence and uniqueness result of a regular solution using a comparison principle and a fixed point argument for the GCZ model. Next, we establish a time-based global existence result for the GB model, based on notions of discontinuous viscosity solutions and a new estimate of total solution variation, as well as finite velocity propagation of the governed equations. This result is extended also to the cas of general Hamilton-Jacobi equation systems. Finally, we propose a semi-explicit numerical scheme allowing the discretization of the GB model. Based on the theoretical study, we prove that the discrete solution converges toward the continuous solution, as well as an estimate of error between the continuous solution and the numerical solution has been established. Simulations showing the robustness of the numerical scheme are also presented
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Chen, Yu-Hung, and 陳宇宏. "Plastic Analysis of Extrusion Wear." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/27031326842910098058.
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碩士國立臺灣大學
機械工程學研究所
97
Extrusion wear is a new phenomenon which was discovered in recent years. We can see from the pin-on-disc testing that the pin wear became severe suddenly when the speed and load exceeded some critical values. Meanwhile, the metal became softer because of high temperature and was sheared by tangential force. Some debris was thus formed with shinning sparks and its components were almost metal, but not oxide. This mechanism is quite different from oxidational wear and is now termed as extrusion wear. In this study, mechanics of plasticity was used to evaluate the extrusion wear of pin with Gaussian distribution assumption of asperity height. The result shows that there was still 2 to 10 times the gap between theoretical and real values. Lots of assumption and simplification was necessary in this study because the interaction between two contacting bodies is complicated and microcosmic. So we thought the gap may be acceptable, and it also indicated that plastic analysis is a feasible direction to analyze the behavior of extrusion wear.
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ISSAC, CHIOU, and 邱璨坤. "Elasto-Plastic Analysis of Braced Columns." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/29433457827981177544.
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碩士中原大學
土木工程研究所
86
This research is to study the material-geometric non-linear behaviorof braced columns by finite element method. In the analysis, the lateral bracing is modeled by an elastic translational spring, and initial deflection is applied to simulate the imperfection of the column caused by improper construction or other reasons. Stiffness matrix of the beam-column is derived from plastic theory; then followed by the geometric stiffness matrix, plastic stiffnessmatrix and the linear and nonlinear element coordinate transformation coefficients. Nonlinear analysis is carried out using Newton-Raphson method to trace the non-elastic behavior of thestructure. Analysis results show that initial deflection has a certain adverse effect on the bearing capacity of the column, andthe stiffness of the lateral bracing can increase the bearingcapacity effectively. The slenderness ratio is a function ofthe stiffness and location of the lateral bracing and the radius ofgyration of the cross-section. This research shows that slendernessratio is the main factor affecting the bearing capacity of a column,which is basically the same approach adopted by most building codes.
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Lin, Chin-hui, and 林錦輝. "Plastic Hook Design and Stress Analysis." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40629280629546755572.
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碩士逢甲大學
材料與製造工程所
98
According to consumers demand of plastic hook for hanging articles, the study is to simulate the stress changes of initial L type, arc type and arc type with uniform thickness of ABS plastic hooks structure while bearing weight. After optimized analysis and improvement, it makes a completed research and development process of implement CAE analysis. With the software integration, CAD (Pro / ENGINEER) and CAE (Pro / Mechanica), as well as concurrent engineering of development process, we can get the best design of plastic hook structure for 1.5kg (14.7N) loading capacity among three different types of plastic hooks (the initial L-type, arc type and arc type with uniform thickness) and two different loading areas (free edge or a cantilever beam). It provides designers a reference for implement CAE analysis.
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JHAN, WEI-SHENG, and 詹為盛. "Mold Flow Analysis for Plastic Glasses." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/47322802938486203144.
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碩士高苑科技大學
機械與自動化工程研究所
104
Abstract In this paper, using Moldex3D mold flow analysis software, analysis of plastic glasses. Plastic glasses material is selected Moldex 3D material library PC CALIBRE 302 5 DOW and PMMA ACRYREX CM205 CHI-MEI, progress in the use of the gate and into the gate at a different gate and materials analysis. Materials analysis process, PMMA ACRYREX CM205 CHI-MEI progress gate volumetric shrinkage, X warp direction, Y direction warp, Z warp direction, optimum residual stress; PC CALIBRE 302 5 DOW Further progress gate Total the amount of displacement warping best. In terms of data flow analysis in comparison, motivated gate will gate into good ratio, the material PMMA ACRYREX CM205 CHI-MEI will PC CALIBRE 302 5 DOW good ratio.Keywords：Plastic Glasses , Volumetric Shrinkage , Residual Stress
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Zhang, Jia-Rong, and 張嘉榮. "The Finite Element Analysis for Plastic Magazine." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/44emkq.
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碩士國立成功大學
工程科學系碩博士班
90
Light weapons are more light capacities and high moblities in the war now,so the quality of weapons is more important.In this article,I study about T65K2 refile's magazine for ligt capacity and high mobility.For this purpose,it needs to use macromolecular compounds' quality.But we may ask if macromolecular compounds' strength is good as aluminum alloy?SO I use two modes to analyse the stress of magazine's entrance by computer software ANSYS.One is half magazine's entrance finite element analysis,and the other is whole magazine finite element analysis.Two modes all use aluminum alloy quality and macromolecular compounds quality.the result shows that the ratio between Young's modulus and maximum displacement is 1/35.The theory is governing equation of computer software ANSYS.
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Chang, Chia-Lin, and 張嘉麟. "Plastic Analysis of Special Cable-Stayed Bridge." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46853714948642497548.
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碩士中原大學
土木工程研究所
97
The purpose of this study concerns with the plastic analysis of cable-stayed bridges by using increment-varied stiffness method. In the increment-varied stiffness method, the nonlinear plastic problem is treated as a piecewise linearized problem. Three kinds of systems, i.e., floating system, multi-supported floating system and pylon rigidly connected to the girder and continued to a lower pier, are used in this research. A finite element computation procedure using increment-varied stiffness method is setup for the nonlinear plastic analysis of those structures to evaluate the ultimate load-carrying capacity. The results will assist the rational retrofit of existed cable-stayed bridges.
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Chen, Zu-Hong, and 陳志宏. "Analysis of plastic deformation for perforated sheets." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/02942695189391053699.
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碩士國立臺灣大學
機械工程學系研究所
86
A yield criterion of sheets with circular perforations in a hexagonal pattern was investigated. The new yield criterion was compared with published literature, and was confirmed by the finite element analysis results in the whole range of ligament efficiency of the perforated sheets. The developed yield criterion can also be applied to analyze stretching of dot — type shadow mask. The goal of this thesis was to establish a computer simulation model for the deformation of the perforated sheets. This thesis introduced the concept of the method of computer simulation and derived a formulation for the future study of the simulations of the perforated sheets. Key Words : yield criterion, hexagonal pattern, shadow mask, ligament, finite element
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Tsai, Ting-Kai, and 蔡定凱. "The Finite Element Analysis of Plastic Sunglasses." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/84974227083015135311.
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碩士高苑科技大學
機械與自動化工程研究所
97
The purpose of this paper is to analyze the mechanics behavior of the plastic sunglasses using finite element method. In static analysis, it uses CATIA, SolidWorks, and ANSYS to simulate the impact by accident on different positions of the glasses with different forces. The von Mises stress theory is adopted to predict the failure. In transient analysis, it is subjected with different steel ball’s velocity in different positions in order to simulate the situation of the standard velocity impact test after manufacturing. The CAM software CATIA is used first to draw the part and then transfers the file to finite element soft ANSYS file. The analysis results are compared with the experiments offered by cooperated company and give them some valuable suggestions.
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WANG, YING-CHUN, and 王穎諄. "Cyclic Elastic-Plastic Analysis of Truss Structures." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/51020220639178183269.
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碩士中華科技大學
飛機系統工程研究所
104
This thesis investigates elastic shakedown limit loads and elastic-plastic analysis of structures subjected to cyclic loads made of nonlinear kinematic hardening materials. In the thesis, the step-by-step analysis of the computer code ABAQUS is applied to consider elastic-perfectly plastic and kinematic hardening materials, respectively. Parametric studies are made to study the prediction of shakedown limit loads and the relationship between shakedown limit loads and plastic limit loads. Also, validations and comparisons are made between the results obtained by ABAQUS and MATLAB. Moreover, Armstrong-Frederick kinematic hardening model is utilized in the related parametric studies
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Reddy, Annem Narayana. "A New Variable Moduli 14-Node Element For Elasto-Plastic Analysis." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1358.
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Chi, Chao-Ming. "Plastic Limit Analysis of Offshore Foundation and Anchor." 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8452.
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This study presents the applications of plastic limit analysis to offshore foundations and anchors, including the drag embedment anchors (DEAs) for mobile offshore drilling units (MODU’s) and spudcan foundations for jack-up platforms. In deep waters, drag embedment anchors are an attractive option for mooring of semisubmersible platforms due to low installation cost and high holding capacity; on the other hand, jack-up platforms are more stable than semisubmersible platforms but only can be placed in shallow waters.
The analyses of anchor capacities are developed for an idealized anchor comprising a rectangular fluke, a cylindrical shank, and a metal chain connected to the shank at the padeye. The anchor trajectory prediction during drag embedment is also developed by considering anchor behavior in conjunction with the mechanics of the anchor line. The results of simulations show that anchors approach at equilibrium condition rapidly during the embedment and both the normalized holding capacity and the anchor line uplift angle remain constants in this stage. Besides the geometry of the fluke, the properties of the shank and soil are also crucial factors in the anchor-soil interaction behavior.
Partial failure of mooring systems for floating structures will subject drag anchors to loads having an appreciable component outside of the intended plane of loading. Partial failure of mooring systems during hurricanes in recent years have generated an interest in understanding drag anchor performance under these conditions. The analysis presents the simulations of three dimensional trajectories of an anchor system subjected to an out-of-plane load component. For the conditions simulated in the example analyses, the anchor experienced a modest amount of continued embedment following partial failure of the mooring system; however, the ultimate embedment and capacity of the anchor is much less than what would have developed if the anchor had continued in its original trajectory within the plane of intended loading.
The analyses of the spudcan foundation of jack-up units include preloading, bearing capacity, and the displacement assessment. When the contribution of the soil moment resistance is considered, a three-stage assessment procedure is recommended: superposing environmental forces on the plot of yield surface, determining the value of yield function corresponding to the external forces, and computing the factor of safety of the spudcan. The results of the assessment may be ambiguous while the different yield functions are employed to analyze the spudcan in soft clay.
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Rabbani, Musharaf. "Analysis and processing issues of plastic color mismatch." Thesis, 2011. http://hdl.handle.net/10155/147.
Full textAbstract:
Color is a visual characteristic which imparts the ability to categorize different
objects. When light strikes an object, there are three possibilities as to what can happen.
The light may be reflected, refracted or scattered. Human perception of color is due to a
combination of these. Plastics are polymeric materials. Polymers are generally colorless
and need colorants in order to have some color. One or more pigments in certain ratios
can be used to give a specific color to plastics. Slight variations in the proportions of
either of the used pigments, or their dispersion, may result in a color that is different from
the desired one. There can also be many other reasons for color mismatch such as
processing or degradation effects.
This study utilized the historical data records of SABIC IP to look at effects of
changing Grade on color (i.e. when the same color is produced from resin blends which
may have different amounts of resins, pigments or additives). These records were also
used to study effects of change in screw diameter and configuration on color (i.e. when
the same grade of a color is produced on two different production lines, different screw
diameters and configurations).
The effects of the processing parameters on the colors were also investigated by
carrying out experiments using a twin screw extruder at SABIC IP’s plant in Cobourg.
Resins, pigments and additives were dry blended and extruded while being subjected to
different processing conditions. Three processing parameters, namely temperature, rpm
and feed-rate, were chosen for the study. A three level factorial design of experiments
was used. An analysis of variance (ANOVA) has been utilized to find the effects of
individual parameters on color and the interaction between two parameters and their
cumulative effect on color.UOIT
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Yang, Wen-Pin, and 楊文彬. "The CAE Warpage Analysis of Plastic InjectionMolding Parts." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/754g4p.
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碩士國立臺北科技大學
製造科技研究所
98
Using CAE mold flow analysis software to simulate the plastic injection molding process can optimize the runner and gate design of the mold, reduce the test molding times, shorten the mold design hour through, and cost down of the mold making. In this study, Autodesk Mold Flow software will be used to simulate and analyze the total warpage of photo-frame above cover during injection molding. The gate number designed including single gate and double gate in the mold. Three types of plastic materials were used including ABS, ABS+PC, and PC. Finally, total warpage was compared at the three different packing pressures. Results show the minimum total warpage of the single gate is ABS among the three plastic materials, maximum is PC. For the double gate, the minimum total warpage is also ABS material, , maximum is ABS+PC. The advantage of double gate is that can reduce the injection pressure. However, it is not obviously to improving the total warpage. For this reason, the single gate was suggested in this study to safe the plastic material used.
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Chang, Cheng-Ying, and 張正穎. "Elastic and Plastic Stress Analysis of Bolt Threads." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/36w997.
Full textAbstract:
碩士逢甲大學
機械工程學所
100
In structural design, thread is a very critical issue that can never be ignored. This thesis uses a nonlinear finite element method to study the stress distribution of the thread under different fillet radius, depth, structu- re and plastic deformation. The analysis showed that the depth is not changed, increase the root fillet radius can reduce stress concentration of the thread root. In depth change, increase fillet radius will also make the thread root stress decrease, but when the fillet is too large, lead to roots become sharp, it will make the thread root stress increase. Under the plastic deformation, when the first thread of load too large to reach the yield, remaining load will be spread to the second thread, the second thread immediately yield, it will make each thread of the stress tends to average. In addition, change nut structures and parameters of different dimension, study the effect of different dimensions of stress in bolt thread
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Fang, Chieh, and 方傑. "The study of Plastic Conveyor belt tensile Analysis." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/68646485988413041960.
Full textAbstract:
碩士逢甲大學
機械工程學所
98
In this study PP(Polypropylene) as the raw material of plastic conveyor belt product,use irregular of special tensile test fixture design,calculate the tensile test strength, and the data into ABAQUS/Standard software analysis.Analysis process:(a)to define the single specimen size and structure of conveyor ; to construct 3D model by solidwoks software.(b)3D model of the conveyor belt of into CAE structure analysis software ABAQUS.(c)Analysis of force by the specimen during deformation, displacement ,break point, von Mises stress and tensile strength with the experimental data of the control. And the experimental and analytical results that the maximum tensile strength of the specimen can be applied to the actual machine. And clamp connections most likely to have a big ring deformation and facture, because the tensile axis and the sample is not in the same axis, the specimen will be stretched into the curved shape, and obtained by the tensile test occurred after the break point, and state of the specimen and analysis revealed that fit together well.