Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 119-124).

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 154-158).

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 5 uppsatser.

Thesis (M.App.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 90-94). Also available in electronic format on the Internet.

This thesis studies interactions between coupled acoustic domain(s) and enclosing rigid or elastic boundary. Boundary element-finite element (BE-FE) sound-structure interaction models are developed by coupling frequency domain BE acoustic and FE structural models using linear inviscid acoustic and elasticity theories. Flexibility in analyses is provided by discontinuous triangular and quadrilateral elements in the BE method (BEM), and a rectangular plate and a triangular shell element in the FE method (FEM). An analytical formulation is developed for an extended fundamental sound-structure interaction problem that involves locally reacting sound absorptive treatment on interior elastic boundary. This new formulation is built upon existing analytical solutions for a configuration known as the cavity-backed-plate problem. Results from developed analytical formulation are compared against those from independent BE-FE analyses. Analytical and BE-FE analysis results for a selection of cavity-plate(s) interaction cases are given. Single- and multi-domain BE analyses of cavity-Helmholtz resonator interaction are provided as an alternative to modal method of acoustoelasticity. A discrete-form of the existing BE acoustic particle velocity formulation is presented and demonstrated on a basic case study. Both the existing and the discretized BE acoustic particle velocity formulations could be utilized in acoustic studies. A selection of case studies involving fundamental configurations are studied both analytically and computationally (by BE or BE-FE methods). These studies could provide a basis for benchmark case development in the field of acoustics.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Compressive residual stresses (CRS) are beneficial for enhancing the fatigue life of metal components. Shot Peening (SP) is an industrial cold working process that is applied to induce a field of CRS and modify the mechanical properties of the metal component. The SP process involves impacting a surface with tiny shots with forces sufficient to create plastic deformation. The process is governed by a number of important parameters such as the shot size, angle of attack, initial velocity, mass flow rate and the distance from the shot nozzle to the surface being peened. The relationship between the optimal peening outcome, particularly the residual stress distribution of the treated surface, and the peening parameters is still unknown and needs to be investigated further. Manufacturers are interested in producing a uniform peening process for complex geometries which optimises the SP parameters. Modelling the process is complex as it involves the interaction of a metallic surface with a large number of shots of very small diameter. Conventionally, such problems are solved using finite element software to predict stresses and strains of a single shot impact then applying superposition. At the moment there are no Finite Element Method (FEM) modelling solutions involving more than tens of shots. The number of shots and elements required for such a modelling process made the approach unfeasible prior to the work described herein. The objective of this work is to develop an appropriate numerical modelling approach that can better simulate the real SP process. The model will be provided by combining Discrete Element Method (DEM) with FEM. The DEM is employed to get a distribution of impact velocities over space and time which are then implemented into a FEM analysis. A discrete element model with randomly distributed steel shots bombarding a steel component at various velocities has been developed as benchmark example. With this model the SP shot - shot interaction, the shot - target interaction, the surface coverage, angle of impingement, shot size, impact velocity and the overall shot flow can be parametrically studied in details and with little computational effort. The novel approach also proposes a new method to dynamically change the coefficient of restitution for repeated impacts during the simulation and predicts the CRS more effectively. The effects of SP on different materials of relevance to gas turbine engine components will be investigated in order to improve the understanding of the interaction between the shots and the targeted material. Initially, an uncoupled analysis was peforned, in order to assess the capabilities of the two modelling systems, DEM and FEM, to delivery an improved solutuion when combining two commercially available codes. This parametric analysis is performed using the state-of-the-art Discrete Element (DE) application EDEM. In the subsequent part of this work, a dynamic Finite Element (FE) application Abaqus will be used to investigate single shot impacts and to obtain the residual stress distribution. This gives us a prescribed residual stress distribution and peening coverage. A Combined DEM/FEM tool (DEST) is proposed that eliminates any manual pre-processing required for linking/coupling, eliminating the use of two different applications and provide an integrated solution for the simulation of the Shot Peening process. In the subsequent chapter, the implementation of essential tools for the enchanced modelling of Shot Peening process functionalities, such as the nozzle, bounding box, coverage and intensity is described. A number of computational improvements are also implemented to reduce the computation time. The existing binary search is enhanced to self-balancing search tree and further improved to allow insertion and deletion of elements. A bounding box feature which removes shots that move out of the domain during the course of the simulation is also implemented. Experiments featuring single shot impacts are performed to gain better understanding the deformation process in the target material subjected to impact conditions to those occurring in the production peening. The single shot impacts are experimentally examined using SEM and EBSD. During final chapter, case studies are performed to compare the results of the simulations with large-scale experimental work. The coverage of peening of single and multiple nozzles with different angle of impingements are assessed. Finally, possible directions for further research concerning the accurate quantification of material responses to SP are identified in the report.

The goal of this research is to investigate the combined effects of glass fibre reinforcement and molecular orientation in polypropylene-short glass fibre composites. Specimens have been fabricated using the injection moulding process and drawn using a small die drawing rig. The effects of die drawing on the fibre composites are complex, with the drawing process orienting both the polymer molecules and the glass fibres. This may be accompanied by the creation of voids in the polymer matrix and their destruction in the compressive stress field thus restoring the interfacial contact area between fibre and matrix. Unfilled and short glass fibre filled polypropylene specimens, with fibre content 7% wt, 13%wt, 27%wt, and 55%wt, were injection moulded prior to the die drawing process. An experimental program of die drawing within an oven at elevated temperature was conducted for polypropylene filled to various levels and at different strain rates. The specimens drew to draw ratios in the range γ=1.41 to γ=5.6. Mechanical characterization of the test materials has been conducted by examining the tensile stress strain and fracture behaviour under uniaxial conditions. The influence of glass fibre content and drawing conditions (draw ratio) on the fracture toughness and crack propagation was investigated using the double edge notched fracture test. The notch lengths ranged from 1.5 to 2.5 mm for 10 mm wide specimens. The critical stress intensity factor increased as the fibre content increased up to a limiting filler level. The fracture toughness of both unfilled and fibre filled polypropylene were found to be highly dependent on draw ratio. The results were analysed to find out the optimal draw ratio and fibre content that yielded the maximum modulus, strength and fracture toughness. Data showed that, at a given draw ratio, modulus, strength and fracture toughness increased with increasing fibre content to a maximum and then decreased. The optimum material was obtained at a draw ratio of 2.5 and filler loading 13wt%.

O design de calçados femininos de salto alto frequentemente tem características de projeto com foco no styling ao invés de projeto centrado no usuário, uma vez que a estética prevalece em relação ao conforto. No presente trabalho, desenvolve-­-se uma abordagem metodológica para o projeto de calçados, focado na melhor adaptação aos pés dos usuários, representados pelo universo das mulheres, com a característica do \"sob medida\", visando principalmente o conforto. Como estudo de caso considera-­-se o calçado comercial, feminino e de salto alto. A metodologia consiste na uHlização de simulação virtual para análise do desempenho, podendo prever possíveis falhas antes da produção em escala, principalmente pelos estudos dos fenômenos relacionados com as deformações dos materiais sofridas por cargas aplicadas, ou seja, tensão x deformação. A elaboração do modelo de análise ocorreu pela obtenção de dados de pressão plantar realizados em ensaios de baropodometria, uHlizando palmilhas com sensores que medem as pressões instantâneas durante o passo. Os calçados selecionados foram cedidos por uma marca comercial conhecida e atuante no mercado brasileiro há mais de 30 anos, sendo modelos sociais, Hpo sandálias e scarpins, considerados produtos de luxo. Três alturas de salto foram usadas nas medições, e para o mais alto deles, uHlizou-­-se dois modelos, um de salto fino e outro de salto com base retangular. Essas medições são os dados de entrada para o so-ware de análise pelo método dos elementos finitos. As forças aplicadas em uma palmilha virtual simulam as regiões dos picos de pressão obHdas pela baropodometria, caracterizando a distribuição da pressão plantar. Essas análises podem auxiliar novos projetos de calçados, dando o suporte necessário para a idealização de soluções que proporcionem diminuir os picos de pressão, causando assim menor desconforto e maior adequação do projeto às caracterísHcas fisiológicas de cada usuário pela criação de palmilhas anatômicas e personalizadas, como sugere o resultado das análises. Uma vez que é uHlizada uma metodologia que consiga prever o desempenho de um calçado antes da sua fabricação, são inúmeras as vantagens que podem auxiliar na oHmização e melhoria dos calçados existentes, ao reduzir o tempo de desenvolvimento e os custos envolvidos, além de garanHr a qualidade do produto. Tanto o design de calçados comerciais quanto conceituais analisado pelo método dos elementos finitos pode ser inspirado pelos resultados de desempenho, influenciando as escolhas de soluções que auxiliem na definição do melhor projeto. Ao final do trabalho foi desenvolvido um protóHpo experimental de um calçado feminino de salto alto que reforçou a validação da pesquisa. / The design of women\'s high-heeled shoes often has design features with Focus on styling rather than user-centered design, since steHca prevails in Relation to comfort. In the present work, a methodological approach is developed for the Footwear design, focused on the best adaptation to the feet of the users, represented by the Women\'s universe, with the characteristic of \"tailor-made\", mainly aimed at comfort. As a case study it is considered the commercial footwear, feminine and high heels. The methodology Virtual simulation for performance analysis, and can predict possible Prior to scale production, mainly due to the studies of the phenomena related to With the deformations of the materials undergone by applied loads, that is, tension x deformation. A The model analysis was performed by obtaining plantar pressure data In baropodometry tests, using insoles that measure pressures During the step. The selected footwear was given by a trademark Known and active in the Brazilian market for more than 30 years, being social models, Hpo Sandals and scarpins, considered luxury products. Three heel heights were used in the Measurements, and for the highest of them, two models were tested, one with a Rectangular base. These measurements are the input data for the analysis software by the method Of finite elements. The forces applied in a virtual insole simulate the regions of the peaks Pressure obtained by baropodometry, characterizing the plantar pressure distribution. These analyzes can aid in new shoe designs, giving the necessary support for the Solutions that reduce pressure peaks, thus Discomfort and greater suitability of the design to the physiological characteristics of each user by the Creation of anatomical and customized insoles, as suggested by the analysis results. Once That a methodology is used to predict the performance of a footwear prior to its The advantages that can aid in the improvement and improvement of footwear. Reducing development time and costs involved, as well as product quality. Both the commercial and conceptual footwear design analyzed by the Finite element method can be inspired by the performance results, influencing the The choices of solutions that help in the definition of the best project. At the end of the study, Developed an experimental prototype of a high-heeled women\'s shoe that reinforced the Validation of the research.

O design de calçados femininos de salto alto frequentemente tem características de projeto com foco no styling ao invés de projeto centrado no usuário, uma vez que a estética prevalece em relação ao conforto. No presente trabalho, desenvolve-­-se uma abordagem metodológica para o projeto de calçados, focado na melhor adaptação aos pés dos usuários, representados pelo universo das mulheres, com a característica do \"sob medida\", visando principalmente o conforto. Como estudo de caso considera-­-se o calçado comercial, feminino e de salto alto. A metodologia consiste na uHlização de simulação virtual para análise do desempenho, podendo prever possíveis falhas antes da produção em escala, principalmente pelos estudos dos fenômenos relacionados com as deformações dos materiais sofridas por cargas aplicadas, ou seja, tensão x deformação. A elaboração do modelo de análise ocorreu pela obtenção de dados de pressão plantar realizados em ensaios de baropodometria, uHlizando palmilhas com sensores que medem as pressões instantâneas durante o passo. Os calçados selecionados foram cedidos por uma marca comercial conhecida e atuante no mercado brasileiro há mais de 30 anos, sendo modelos sociais, Hpo sandálias e scarpins, considerados produtos de luxo. Três alturas de salto foram usadas nas medições, e para o mais alto deles, uHlizou-­-se dois modelos, um de salto fino e outro de salto com base retangular. Essas medições são os dados de entrada para o so-ware de análise pelo método dos elementos finitos. As forças aplicadas em uma palmilha virtual simulam as regiões dos picos de pressão obHdas pela baropodometria, caracterizando a distribuição da pressão plantar. Essas análises podem auxiliar novos projetos de calçados, dando o suporte necessário para a idealização de soluções que proporcionem diminuir os picos de pressão, causando assim menor desconforto e maior adequação do projeto às caracterísHcas fisiológicas de cada usuário pela criação de palmilhas anatômicas e personalizadas, como sugere o resultado das análises. Uma vez que é uHlizada uma metodologia que consiga prever o desempenho de um calçado antes da sua fabricação, são inúmeras as vantagens que podem auxiliar na oHmização e melhoria dos calçados existentes, ao reduzir o tempo de desenvolvimento e os custos envolvidos, além de garanHr a qualidade do produto. Tanto o design de calçados comerciais quanto conceituais analisado pelo método dos elementos finitos pode ser inspirado pelos resultados de desempenho, influenciando as escolhas de soluções que auxiliem na definição do melhor projeto. Ao final do trabalho foi desenvolvido um protóHpo experimental de um calçado feminino de salto alto que reforçou a validação da pesquisa. / The design of women\'s high-heeled shoes often has design features with Focus on styling rather than user-centered design, since steHca prevails in Relation to comfort. In the present work, a methodological approach is developed for the Footwear design, focused on the best adaptation to the feet of the users, represented by the Women\'s universe, with the characteristic of \"tailor-made\", mainly aimed at comfort. As a case study it is considered the commercial footwear, feminine and high heels. The methodology Virtual simulation for performance analysis, and can predict possible Prior to scale production, mainly due to the studies of the phenomena related to With the deformations of the materials undergone by applied loads, that is, tension x deformation. A The model analysis was performed by obtaining plantar pressure data In baropodometry tests, using insoles that measure pressures During the step. The selected footwear was given by a trademark Known and active in the Brazilian market for more than 30 years, being social models, Hpo Sandals and scarpins, considered luxury products. Three heel heights were used in the Measurements, and for the highest of them, two models were tested, one with a Rectangular base. These measurements are the input data for the analysis software by the method Of finite elements. The forces applied in a virtual insole simulate the regions of the peaks Pressure obtained by baropodometry, characterizing the plantar pressure distribution. These analyzes can aid in new shoe designs, giving the necessary support for the Solutions that reduce pressure peaks, thus Discomfort and greater suitability of the design to the physiological characteristics of each user by the Creation of anatomical and customized insoles, as suggested by the analysis results. Once That a methodology is used to predict the performance of a footwear prior to its The advantages that can aid in the improvement and improvement of footwear. Reducing development time and costs involved, as well as product quality. Both the commercial and conceptual footwear design analyzed by the Finite element method can be inspired by the performance results, influencing the The choices of solutions that help in the definition of the best project. At the end of the study, Developed an experimental prototype of a high-heeled women\'s shoe that reinforced the Validation of the research.