Dissertations / Theses on the topic 'Grinding, Finite Element Method, Residual Stresses'
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Mahdi, Mofid. "A NUMERICAL INVESTIGATION INTO THE MECHANISMS OF RESIDUAL STRESSES INDUCED BY SURFACE GRINDING." University of Sydney, Mechanical, 1998. http://hdl.handle.net/2123/413.
Full textShah, Syed Mushtaq Ahmed. "Prediction of residual stresses due to grinding with phase transformation." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00679816.
Full textGarza-Delgado, Abelardo. "A study of casting distortion and residual stresses in die casting." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196175848.
Full textAl-Zkeri, Ibrahim Abdullah. "Finite element modeling of hard turning." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1181928433.
Full textPhilander, Oscar. "Mathematical modelling of welding : sensitivity of residual stresses and thermal dilatations on welding parameters." Thesis, Peninsula Technikon, 1998. http://hdl.handle.net/20.500.11838/2227.
Full textIn South Africa, the determination of residual stress distribution and undesirable metallurgical phase fractions that are formed in components during welding are been dealt with in a destructive or semi-destructive manner. This dissertation is an attempt at enhancing the acquisition of residual components found in welded structures. It shows how finite element methods can be used to obtain these results. TIG welding is modeled as a thermo-mechano-metallurgical (TMM) problem. The mathematical and finite element models for welding described in this study is based on the work performed by Ronda and Oliver. These models has not yet fully been incorporated into any of the existing computational tools and therefor, a commercial computational software program, SYSWELD 2, was employed to perform the welding simulations. The Leblond material models are incorporated into this software program, and the model that is used for this study is described in this text. Computational simulations were performed to study the effects that the sensitivity of welding parameters would have on the resulting shape and size of Heat Affected Zones, depth and width of penetration, temperature fields, metallurgical solid phase fractions, as well as residual stress distribution and deformation. The results of these simulations were compared to laboratory experiments.
Maczugowski, Maciej. "Numerical simulation of residual stresses in a weld seam : An application of the Finite Element Method." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-65867.
Full textBadr, Elie Antoine. "Estimation of residual stresses induced by autofrettage with an experimental evaluation of the autofrettage process in crossbores of positive displacement pumps /." Access abstract and link to full text, 1994. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9500703.
Full textLiou, Jiann-Haw. "Study of stress developments in axi-symmetric products fabricated by forging and machining /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9737869.
Full textLong, Xin. "Finite element analysis of residual stress generation during spot welding and its affect on fatigue behavior of spot welded joints." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4171.
Full textThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (November 13, 2006) Vita. Includes bibliographical references.
Awang, Mokhtar. "The effects of process parameters on steel welding response in curved plates." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2682.
Full textTitle from document title page. Document formatted into pages; contains xiv, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 83-85).
Meňhert, Samuel. "Vliv modelu zpevnění na výsledky simulace kosoúhlého rovnání." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401548.
Full textTorkaman, Hamid. "Modeling and Analysis of the Shot Peening Process : a Study of the Residual Stresses in an Insert using the Finite Element Method." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-77322.
Full textDawkins, Jeremy James. "Influence of crystallographic orientation in normal and sliding contacts." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24713.
Full textShih, Yi-Pu. "The stress patterns and residual stresses developed in curved die upsetting." Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1175883679.
Full textGolestanian, Hossein. "Modeling of process induced residual stresses and resin flow behavior in resin transfer molded composites with woven fiber mats /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841293.
Full textBarban, Leonardo Manesco. "Análise numérico-computacional das tensões térmicas induzidas pela soldagem." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-23122014-143431/.
Full textWelding is the most used joining process in equipment manufacture by mechanical industry. Due to heat application during welding, varying with torch position and therefore by time, non-uniform expansion and contraction produces thermal stresses, which remains as residual when the component reaches thermal equilibrium. Formation and behavior of these stresses understanding becomes important since on external forces presence the mechanical piece may have it structural integrity compromised. This study aims to analyze thermal stress behavior due to welding evaluating residual stress magnitude and distribution at the process end by the finite element method. First of all fusion welding process by an electric arc are presented and a theoretical explanation about thermal stresses formation during welding is shared. Next is shown a bibliographic research with main techniques to model these problems using the finite element method, including thermal analysis, which involves temperature distribution study, and structural analysis that evaluate resulting stresses. With all theoretical background consolidated an example case of a GTAW process is studied utilizing ANSYS software, comparing numerical results with experimental and numerical data obtained in literature. It is possible to conclude that analyzed model accurately reproduces temperature distribution and also residual stress in the welded specimen proving that a welding process simulation via finite element method is an alternative tool for industry purposes on improving existing process and developing new ones.
Mondardo, Milena Macarini. "Análise da influência de parâmetros do processo de trefilação de barras cilíndricas de aço AISI 1045 via simulação numérica computacional." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/61069.
Full textThis paper aims to analyze the drawing process using simulation and evaluate the influence of process variables such as lubricant (friction coefficient) and angle of die as well as verify the effectiveness of simulation to preview the drawing force, temperature and residual stresses. Experimental work was carried out involving the determination of friction coefficient by means of the ring test and determination of flow curves by compression tests. The calculations of the stress of the process using data from the flow curves and equations from the literature have been carried out. Later on the experimental results were compared to the simulated results. It was also used in addition, the optimized simulation to evaluate the residual stresses and the results were then compared with experimental results obtained by neutron diffraction for the same bars that were extracted from the industrial process. The results are very influenced by the flow stress curve chosen. The simulation was satisfactory for the estimation of the drawing force but must be improved for a better estimation of residual stresses.
Marini, Michelangelo. "Numerical models for the simulation of shot peening induced residual stress fields: from flat to notched targets." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/266179.
Full textMurugaratnam, Kovthaman. "A refined numerical modelling technique for Shot Peening." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:43e0fa12-bf49-425b-9ba6-6b93adaa8a7e.
Full textMartins, Jairo Aparecido. "Analise de tensões residuais em valvulas estampadas por meio da difração de raios-X e do metodo de elementos finitos." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264486.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: A evolução dos materiais, de seus processos de transformação e de diversos componentes mecânicos vêm requerendo cada vez mais o desenvolvimento de técnicas e métodos para sua análise. A transformação de materiais por deformação plástica origina tensões internas chamadas tensões residuais que podem vir a alterar a resposta do componente e/ou sistema quando em uso. Este trabalho tem como objetivo a análise dessas tensões residuais em válvulas dinâmicas estampadas por difração de raios- X e pelo método de elementos finitos. Dentro deste contexto, foi desenvolvido um método alternativo ao usual sen2", para a determinação de tensões residuais por difração de raios- X em pequenas áreas, esse utiliza o método de análise da difração de raios-X usualmente empregada na determinação de tensões residuais em filme finos . Os resultados obtidos na difração de raios-X mostraram-se compatíveis com o processo de deformação estudado e também com os resultados da simulação numérica pelo método de elementos finitos. A comprovação prática desses resultados deu-se pela realização de ensaios de durabilidade em bancada por flexão alternada reversa de uma válvula dinâmica nas seguintes condições de fabricação: a) estampada, b) estampada e deformada plasticamente em regiões de alta solicitação mecânica e c) estampada, deformada plasticamente e com um processo abrasivo adicional empregado para a eliminação de regiões potencialmente danosas ao componente previamente verificadas na simulação. Os resultados obtidos nesses ensaios comprovaram a validade dos métodos empregados para a análise das tensões residuais
Abstract: The continuous development of engineering materials, the new manufacturing processes, and the more complex mechanical parts have required constandy improvement of techniques and methods able to make analyses fast and easy. Metal forming with dimensional changes by plastic deformation results internal stresses, named residual stresses, which can significandy a:ffect the mechanical performance of parts and systems. The main objective of this work is to develop a method to analyze the residual stresses in stamped dynamical valves by X-ray diffraction and by the finite element method. In this context it was developed a sin2", alterna tive method based on the method common1y applied to the determination of residual stresses in metallic thin fUms. The results obtained from X-ray diffraction are coherent to those obtained in the stamping processes and in the simulation by the finite element method. These results were also compared to results from fatigue tests carried out with a laboratory bench (cantilever alterna te reversed bending) with dynamic valves in the conditions: a) as blanked , b) blanked and plastica11y deformed on the regions subjected to high 10005, and c) blanked, plastica11y deformed and grinded to eliminate potential dangerous regions as revea1ed in the simulation. The results obtained in the fatigue tests confumed the validity of the methods applied in this work to analyze the residual stresses
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
SOARES, MARIA da C. B. V. "Influencia das tensoes residuais no comportamento em fadiga e fratura de ligas metalicas." reponame:Repositório Institucional do IPEN, 1998. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10668.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Medeiros, Iury Zottele. "Modelagem optomecânica de fibras ópticas microestruturadas." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259176.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Atualmente as fibras ópticas microestruturadas (FOMs) estão sendo cada vez mais exploradas por possuírem geometricamente um maior grau de liberdade em seu projeto, além da possibilidade do uso de materiais não usados em fibras convencionais, proporcionando características ópticas antes inalcançáveis. Sendo assim, através do uso do programa para obtenção de modos de propagação pelo método dos elementos finitos totalmente vetorial disponível no grupo do Prof. Dr. Hugo E. H. Figueroa, foram apresentadas técnicas de simulação em FOMs multimodais, as quais foram implementadas em FORTRAN e adicionadas ao programa principal. Neste trabalho também foi estudado os esforços mecânicos gerados pelo o uso de diferentes materiais na constituição da FOM em seu processo de fabricação. Tais esforços são conhecidos como tensão residual térmica e proporcionam variações anisotrópicas dos índices de refração dos meios que compõem as FOMs. Primeiramente o cálculo das tensões residuais foi feito analiticamente para uma geometria generalizada de FOM, e então tratando-as como uma pertubação no modo propagante analisado anteriormente pelo programa de análise modal. Por ultimo foi implementado um código para o cálculo estimativo da birrefringência de fase e de grupo levando em conta os esforços mecânicos induzidos no processo de fabricação, portanto o objetivo final foi alcançado
Abstract: Nowadays micro-structured optical fibers (MOFs) are being increasingly exploited since they have a greater geometrical flexibility in its project, in addition to the possibility of using un-conventional materials, providing optical features unreachable before. Therefore, a full-vectorial finite element modal solver developed by Prof. Dr. Hugo E. H. Figueroa's group was used, since it has already proved its efficiency. New techniques for multimodal MOFs simulation were presented, they were implemented using FORTRAN and then added to the main program to make the search for the propagation constants easier. Mechanical stress was also studied. It is generated by the use of different materials whithin the MOF constitution, in its manufacturing process. These stresses are known as thermal residual stresses and they provide variations of the anisotropic refractive indexes of the MOFs media. First, the calculation of the residual stresses was done analytically for a general geometry of MOF, and then they were treated as perturbations in the propagating mode, discussed previously by the full-vectorial finite element modal solver. Finally a code was implemented to estimate the phase and group birefringence, considering the mechanical stresses induced in the manufacturing process, therefore the ultimate goal was achieved
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
Sonde, Abayomi Emmanuel. "Etude et modélisation de procédés innovants de mise en compression de surfaces : Traitements de surface par cavitation et par impulsions électromagnétiques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI015/document.
Full textSurface treatments methods like shot peening are used to introduce compressive residual stresses in metallic materials. The compressive stresses prevent the initiation and growth of cracks and hence improve the fatigue life of mechanical parts. The drawbacks and limitations of the existing processes generally used for this purpose are known and have been highlighted in many studies. These are, among others, an important surface modification (roughness), a limited compressive depth, difficulties in execution, debris and contamination problems, etc. Therefore, the interest in new surface treatment methods, which permit to obtain equivalent or even better compressive results while avoiding the previous problems, are growing. Cavitation peening and electromagnetic pulse peening are part of these innovative processes which modeling is the aim of this PhD thesis. Cavitation peening is a process of surface treatment which acts by the generation of cavitation bubbles near the workpiece surface. The modeling of this process is challenging because of the complexity of cavitation phenomenon and the main problematic point is the determination of the mechanical loading on the material due the bubbles collapse. In this thesis, an approach of modeling for cavitation peening based on the study of the dynamics of cavitation bubbles is proposed. Spherical and aspherical collapse of bubbles near a solid surface are studied by some numerical and analytical models. These two sources of loading pressures have been compared and a macroscopic model for cavitation peening have been derived by associating the numerical simulation of the cavitation jet and the localization of the cavitation zone. The comparison between the final residual stress profile calculated with the proposed model and the experimental results were satisfactory. Electromagnetic pulse peening (EMP) is a contactless process of surface treatment which could be used to introduce compressive residual stresses in conductive materials, by the generation of a high transient electromagnetic field. Laplace forces induced in the material by magnetic induction are the source of the material plastic deformation and compressive residual stresses introduction. To predict the EMP results, a numerical model have been built for the process simulation. The model, based on finite element method, coupled successfully electromagnetic and mechanical phenomena by using a sequential-coupled approach. It was proven theoretically, by the study of a reference case, that compressive residual stresses could be induced in metallic materials like nickel-based (Inconel) or aluminum alloys by the means of the present process. It was also shown by the calculations that much higher compressive depths than those of conventional peening processes could be achieved. The parametric study exhibited the influence of the maximum current intensity and frequency which affect both the compressive depth and the maximum residual stress
Novotný, Lukáš. "Návrh a realizace experimentálního zařízení pro určování zbytkové napjatosti ohýbaných vzorků." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382570.
Full textCheng, Wentao. "In-plane shrinkage strains and their effects on welding distortion in thin-wall structures." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124049585.
Full textTitle from first page of PDF file. Document formatted into pages; contains xx, 268 p.; also includes graphics (some col.). Includes bibliographical references (p. 256-268). Available online via OhioLINK's ETD Center
Silva, Evandro Cardozo da. "Analise numerica do processo corformação de chapas metalicas por jateamento de esferas." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264439.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: O grande desafio do engenheiro no processo de jateamento de esferas, é obter o perfil da tensão residual e a deformação final da peça com precisão. Pois a solução analítica, os resultados experimentais e as simulações numéricas, que possam ser validados, ainda não são totalmente dominados, devido a complexidade do problema de contato dinâmico não linear do impacto que envolve várias disciplinas da elasticidade e plasticidade estática e dinâmica. É preciso reconhecer os vários parâmetros que influenciam o processo e obter um modelo de simulação numérica 3D de elementos finitos (EF) dinâmica e estática, utilizando ferramentas comerciais consagradas, que tenha relativa precisão e possa ser validado ao se caracterizar a tensão residual mecânica induzida e conseqüente deformação. O estudo de modelos estáticos de carregamento equivalente são limitados pela precisão da temperatura e pressão que da a forma final da peça. No modelo de EF elasto-plástico dinâmico 3D do impacto simples, identifica-se que a camada deformada plasticamente, a tensão residual superficial e sub-superficial são influenciados significativamente pelas características da esfera. Além disso, a separação entre as esferas no impacto simultâneo alteram o desenvolvimento da região plástica. Modelos de impactos múltiplos são implementados com base nestes resultados para a condição de impacto concentrado e disperso de forma semialeatória para modelos reduzidos da peça discretizada
Abstract: Shot peen forming presents a great challenge to engineers to get a precise residual stress and the correct final plastic strain distribution within the formed parts. Because there is not a complete knowledge on analytical solutions, experimental results and numerical simulations are commonly used due to the complex dynamic contact of nonlinear impact problems that involve many disciplines on static and dynamic elasticity and plasticity. Therefore, it is essential to know the parameters that affect the process to obtain a static and dynamic 3D finite element (FE) numerical model to simulate peen forming using powerful FE commercial codes that have relative precision and give results that can be validated and consequently induced mechanical residual stress and consequent deformation can be characterized. The study of equivalent static load models are limited by the precision of temperature and pressure to calculate the correct deformed shape. In the elastic-plastic 3D dynamic FE model with a single impact, the shot characteristics influence the thickness plasticity, and the superficial and under surface residual stress. Besides, the separation distance between adjacent shots changes the development of the plastic region. Multiple shot impacts models are implemented based in these results for concentrate and partial randomic dispersed impact conditions to reduce the models of the target
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
Taro, Mandikizinoyou. "Modélisation et simulation des procédés de mise en compression des surfaces à très grandes vitesses de déformation par méthode semi-analytique." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0105/document.
Full textThe failure of the mechanical parts is very often initiated by a surface defects. Consequently, the generation of compressive residual stresses on mechanical parts by introducing a heterogeneous plastic strain improves the resistance to fatigue and increases the lifetime of the parts. Among the processes making it possible to introduce residual stresses into the parts, the laser shock peening is more interesting for several reasons. On the one hand, it makes it possible to produce pressures on the surface of material of about 1 to 6 going GPa over short pulse times from 3 to 30 nanoseconds. In addition, he gives the opportunity of introducing residual stresses of compression on a certain depth while preserving the initial state of the treated part. The numerical simulation becomes necessary to determine the best physical phenomena involved. Thus, the semi-analytical method offers a lot of advantages, in particular the simplicity of the models and the computation times saving. This method was never extended to the dynamic problems. In this thesis the semi-analytical method was extended to the dynamic problems and the model implemented is applied for the simulation of the Laser process of shock
Boyer, Vincent. "Modélisation du grenaillage d’un alliage de nickel avec prise en compte de l’écrouissage et de la microstructure." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0030.
Full textShot-peening in a surface treatment used in the industry to enhance fatigue life of a mechanical part. Nonetheless, this process remains empirical as complex phenomena linked with residual stress relaxation are not well understood yet. For these reasons, peening step of turbine disks produced by Safran Aircraft Engines, made in Inconel 718, is not considered in the dimensioning phase of the part. Today there is a need for a precise prediction of the process and the life enhancement of peened parts. This thesis is part of the CONDOR project, the objective of which is to answer this need. This work is the first step, and its goal is to build a numerical model of shot-peening able to predict the work-hardening state after the process. In fact this parameter is known to have an important role in the relaxation of residual stress.Complete assessment of the mechanical behavior of Inconel 718 is first proposed. Then the numerical model is built, able to adress the stress and work-hardening state of the peened part. A statistical approach is also proposed. An important XRD experimental campaign on peened sampled was led to correlate the model. Finally, the simulation is used to predict the mechanical state after shot-peening
Capron, Adélie. "Towards the predictive FE analysis of a metal/composite booster casing’s thermomechanical integrity." Doctoral thesis, Universite Libre de Bruxelles, 2020. https://dipot.ulb.ac.be/dspace/bitstream/2013/314767/5/contratAC.pdf.
Full textDoctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
Štegnerová, Kateřina. "Popis šíření trhlin v polích silně nehomogenních a reziduálních napětí." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399210.
Full textMaricic, Luke A. "Thermo-mechanical Behaviour of Turbine Disc Assembly in the Presence of Residual Stresses." Thesis, 2013. http://hdl.handle.net/1807/43135.
Full text