Дисертації з теми "Finite element methods (FEMs)"
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Kleditzsch, Stefan, and Birgit Awiszus. "Modeling of Cylindrical Flow Forming Processes with Numerical and Elementary Methods." Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-97124.
Повний текст джерелаBreslavsky, D. V., V. O. Mietielov, O. K. Morachkovsky, S. O. Pashchenko, and О. А. Tatarinova. "Asymptotic methods and finite element method in cyclic creep-damage problems." Thesis, Львівський національний університет ім. І. Франка, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/19395.
Повний текст джерелаCamacho, Fernando F. "A Posteriori Error Estimates for Surface Finite Element Methods." UKnowledge, 2014. http://uknowledge.uky.edu/math_etds/21.
Повний текст джерелаWang, Sili. "An ABAQUS Implementation of the Cell-based Smoothed Finite Element Method Using Quadrilateral Elements." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416233762.
Повний текст джерелаWitkowski, Thomas. "Software concepts and algorithms for an efficient and scalable parallel finite element method." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-141651.
Повний текст джерелаSoftwarepakete zur numerischen Lösung partieller Differentialgleichungen mit Hilfe der Finiten-Element-Methode sind in vielen Forschungsbereichen ein wichtiges Werkzeug. Die dahinter stehenden Datenstrukturen und Algorithmen unterliegen einer ständigen Neuentwicklung um den immer weiter steigenden Anforderungen der Nutzergemeinde gerecht zu werden und um neue, hochgradig parallel Rechnerarchitekturen effizient nutzen zu können. Dies ist auch der Kernpunkt dieser Arbeit. Um parallel Rechnerarchitekturen mit einer immer höher werdenden Anzahl an von einander unabhängigen Recheneinheiten, z.B.~Prozessoren, effizient Nutzen zu können, müssen Datenstrukturen und Algorithmen aus verschiedenen Teilgebieten der Mathematik und Informatik entwickelt und miteinander kombiniert werden. Im Kern sind dies zwei Bereiche: verteilte Gitter und parallele Löser für lineare Gleichungssysteme. Für jedes der beiden Teilgebiete existieren unabhängig voneinander zahlreiche Ansätze. In dieser Arbeit wird argumentiert, dass für hochskalierbare Anwendungen der Finiten-Elemente-Methode nur eine Kombination beider Teilgebiete und die Verknüpfung der darunter liegenden Datenstrukturen eine effiziente und skalierbare Implementierung ermöglicht. Zuerst stellen wir Konzepte vor, die parallele verteile Gitter mit entsprechenden Adaptionstrategien ermöglichen. Zentraler Punkt ist hier die Informationsaufbereitung für beliebige Löser linearer Gleichungssysteme. Beim Lösen partieller Differentialgleichung mit der Finiten Elemente Methode wird ein großer Teil der Rechenzeit für das Lösen der dabei anfallenden linearen Gleichungssysteme aufgebracht. Daher ist deren Parallelisierung von zentraler Bedeutung. Basierend auf dem vorgestelltem Konzept für verteilten Gitter, welches beliebige geometrische Informationen für die linearen Löser aufbereiten kann, präsentieren wir mehrere unterschiedliche Lösermethoden. Besonders Gewicht wird dabei auf allgemeine Löser gelegt, die möglichst wenig Annahmen über das zu lösende System machen. Hierfür wird die FETI-DP (Finite Element Tearing and Interconnect - Dual Primal) Methode weiterentwickelt. Obwohl die FETI-DP Methode vom mathematischen Standpunkt her als quasi-optimal bezüglich der parallelen Skalierbarkeit gilt, kann sie für große Anzahl an Prozessoren (> 10.000) nicht mehr effizient implementiert werden. Dies liegt hauptsächlich an einem verhältnismäßig kleinem aber global verteilten Grobgitterproblem. Wir stellen eine Multilevel FETI-DP Methode vor, die dieses Problem durch eine hierarchische Komposition des Grobgitterproblems löst. Dadurch wird die Kommunikation entlang des Grobgitterproblems lokalisiert und die Skalierbarkeit der FETI-DP Methode auch für große Anzahl an Prozessoren sichergestellt. Neben der Parallelisierung der Finiten-Elemente-Methode beschäftigen wir uns in dieser Arbeit mit der Ausnutzung von bestimmten Voraussetzung um auch die sequentielle Effizienz bestehender Implementierung der Finiten-Elemente-Methode zu steigern. In vielen Fällen müssen partielle Differentialgleichungen mit mehreren Variablen gelöst werden. Sehr häufig ist dabei zu beobachten, insbesondere bei der Modellierung mehrere miteinander gekoppelter physikalischer Phänomene, dass die Lösungsstruktur der unterschiedlichen Variablen entweder schwach oder vollständig voneinander entkoppelt ist. In den meisten Implementierungen wird dabei nur ein Gitter zur Diskretisierung aller Variablen des Systems genutzt. Wir stellen eine Finite-Elemente-Methode vor, bei der zwei unabhängig voneinander verfeinerte Gitter genutzt werden können um ein System partieller Differentialgleichungen zu lösen
Pacheco, Roman Oscar. "Evaluation of Finite Element simulation methods for High Cycle Fatigue on engine components." Thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148779.
Повний текст джерелаCascio, Michele. "Coupled Molecular Dynamics and Finite Element Methods for the simulation of interacting particles and fields." Doctoral thesis, Università di Catania, 2019. http://hdl.handle.net/10761/4120.
Повний текст джерелаSzegda, Damian. "Experimental investigation and computational modelling of the thermoforming process of thermoplastic starch." Thesis, Brunel University, 2009. http://bura.brunel.ac.uk/handle/2438/3445.
Повний текст джерелаFerro, Newton Carlos Pereira. "Uma combinação MEC/MEF para análise de interação solo-estrutura." Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-08122017-102331/.
Повний текст джерелаIn the present work a combination of the Boundary Element Method (BEM) and the Finite Element Method (FEM) is used for pile-soil interaction analyses, considering the soil as a homogeneous, three-dimensional and infinite medium. The three-dimensional infinite continuous medium is modeled by the BEM, and the piles are, considered as beam elements, modeled by the FEM. This combination also is used for studying the interaction of plates sitting on a continuous medium. The pile equations generated from the FEM are combined with the medium equations generated from the BEM, resulting a complete equation system. Manipulating properly this equation system, a set of stiffness coefficients for the system soil-pile is obtained. Finally, to make the model more comprehensive, it presented a formulation to take into account the soil nonlinear behavior at the pile interface.
Janhunen, Tony, and Martin Mikus. "Dynamisk analys och utmattningskontroll med hjälp av fältmätningar och FEM : Fallstudie över SL:s Bro norr om Söderströmsbron." Thesis, KTH, Structural Design and Bridges, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12228.
Повний текст джерелаFöljande examensarbete omfattar en fallstudie av Bro norr om Söderströmsbron, en tunnelbanebro i stål med fyra spår. Den byggdes 1956 som en del av förbindelsen mellan station Gamla stan och station Slussen i Stockholm. I fallstudien, som är ett samarbete mellan KTH och SL, ingår att bedöma brons dynamiska egenskaper, tillstånd avseende utmattning samt att skapa en finita elementmodell av bron. Vidare begränsas fallstudien till brokonstruktionen för det spår som går närmast slussen mellan Mälaren och Saltsjön, och som i dagsläget utgör gröna tunnelbanelinjen mot Farsta strand, Hagsätra och Skarpnäck.
Under 2005 trafikerades det aktuella spåret under högtrafik av 30 tåg i timmen och under lågtrafik av 15 tåg i timmen. När tåg passerar visar bron stora förskjutningar och glapp mellan sliprar och underliggande stålkonstruktion. Dessa förskjutningar skapar spänningar i stålet och avgörande för brons tillstånd avseende utmattning är antalet skadliga spänningsvidder vid kritiska snitt som inträffat sedan brons färdigställande.
Dagens spänningsvidder mäts med hjälp av töjningsgivare placerade i fältmitt. Mätningen har utförts av KTH, avdelningen för Brobyggnad i samband med examensarbetet. Av intresse är utmattningsrisk för svetsad anslutning mellan lång- och tvärbalkar. Utmattningsrisken beräknas dels med typiserade spänningskollektiv enligt BSK 07, dels med verkliga spänningskollektiv enligt Palmgren-Miners delskadehypotes. Enligt båda metoderna konstateras utmattningshållfastheten vara uttömd, med reservation för förbandsklasser och partialkoefficienter. Kollektivparametern κ enligt BSK 07, vilken vid dimensionering beaktar spänningskollektivets form, uppskattas vara närmare 2/3 än SL:s nuvarande värde 5/6.
Ur responsen från givarna konstateras att den dynamiska förstoringsfaktorn vid 60 km/h varierar mellan 0.63 och 1.43, vilket visar att brons respons har ett stort dynamiskt innehåll.
En finita elementmodell skapas i Abaqus med hjälp av Matlab, med syftet att komplettera resultat från mätningar. I modellen studeras töjning, vertikal förskjutning och acceleration, dynamisk förstoringsfaktor och egenmoder. Den statiska responsen för modell och bro konstateras vara snarlik.
This thesis includes a case study of the Bro norr om Söderströmsbron, a steel subway bridge with four rail tracks. The bridge was built in 1956 as a part of the connection between the two subway stations Gamla stan and Slussen in Stockholm. The case study, which is a collaboration between KTH and SL, includes an evaluation of the dynamic properties of the bridge, in which condition it is regarding fatigue and the creation of a finite element model of the bridge. The case study is limited to the construction carrying the rail track closest to the lock between Mälaren and Saltsjön, and now represents the green subway line towards Farsta strand, Hagsätra and Skarpnäck.
In 2005, the train frequency during rush hour was 30 trains per hour and during low traffic 15 trains per hour. When a train crosses, the bridge shows large displacements and gaps between the sleepers and the underlying steel structure. The displacements cause stresses in the steel and crucial to the bridge fatigue state is the number of damaging stress ranges that have occurred since the opening of the bridge.
The current stress variations are measured using strain gauges positioned in the mid-span. Measurements were carried out by KTH, division of Structural Design & Bridges, during this thesis. Of key interest is a welded edge between the main- and crossbeams. The risk of fatigue is calculated using standardised stress ranges according to BSK 07 and Palmgren-Miners cumulative damage theory. According to both methods, the fatigue life of the bridge is exceeded, with reservations to the detail category and partial coefficients. The stress collective parameter κ according to BSK 07, which in design accounts for the distribution of the stress collective, is estimated closer to 2/3 than SL’s present value of 5/6.
According to the strain gauges, the dynamic amplification factor at 60 km/h varies between 0.63 and 1.43, indicating that the bridge’s response has a large dynamic content.
A finite element model is created in Abaqus using Matlab, with the purpose of complementing results from the measurements. In the model, the strain, vertical displacements and acceleration, dynamic amplification and natural modes are studied. The static response of the model and bridge were found to be similar.
QC 20100707
Mathias, Berggren, and Sonesson Daniel. "Design Optimization in Gas Turbines using Machine Learning : A study performed for Siemens Energy AB." Thesis, Linköpings universitet, Programvara och system, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-173920.
Повний текст джерелаSimeitis, Sven D. "Vergleich von Simulationen mittels Pro/MECHANICA und ANSYS." Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-68443.
Повний текст джерелаGrasso, Eva. "Modelling visco-elastic seismic wave propagation : a fast-multipole boundary element method and its coupling with finite elements." Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00730752.
Повний текст джерелаDavidsson, Johan. "Sobolev Spaces and the Finite Element Method." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-67470.
Повний текст джерелаXie, Mengyin. "X-ray and neutron diffraction analysis and fem modelling of stress and texture evolution in cubic polycrystals." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:c5f8b36c-4728-4c17-8e2e-82b926200019.
Повний текст джерелаDonner, Hendrik. "FEM-basierte Modellierung stark anisotroper Hybridcord-Elastomer-Verbunde." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-229188.
Повний текст джерелаThe analysis of stresses and strains within textile-reinforced rubber components like air springs, tyres, driving belts, and tubes requires accurate as well as efficient computational models. On the one hand, the large deformations, the composite's strongly anisotropic properties, and the large ratio between the size of the cords and the composite necessitate a precise modeling. On the other hand, the highly loaded parts of the components are spatially confined and thus a reduction of the computational effort is desirable. These reduced models are efficient enough for performing engineering-oriented optimizations. The two main priorities of this work are the continuum mechanical modeling of hybrid cords and the development of representative volume elements of highly loaded hybrid cord-rubber composites. Based on an anisotropic plasticity model, which takes the frictional sliding between the filaments within multifilament yarns into account, a finite element model for the simulation of the twisting process of a hybrid cord is the fundament of this work. A comparison with experimental results from tensile and torsional tests as well as images of cross sections validate the proposed hybrid cord model. The basis of the representative volume element is the extension of the classical periodic boundary conditions, which now enable to take the curvature and pressure load into account. Thus, the model is suitable to analyze the highly loaded parts of hybrid cord-rubber composites like the rolling lobe of an air spring. Finally, the set-ups of hybrid cords and hybrid cord-rubber composites are analyzed by means of parameter studies to obtain a minimized loading of the rubber, yarns, and their interface
Dunkelberg, Jr John S. "FEM Mesh Mapping to a SIMD Machine Using Genetic Algorithms." Digital WPI, 2001. https://digitalcommons.wpi.edu/etd-theses/1154.
Повний текст джерелаKingsley, Thomas Charles. "Multidisciplinary design and optimisation of liquid containers for sloshing and impact." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-01242006-100142.
Повний текст джерелаGerstmann, Thoralf. "Erweiterung der Verfahrensgrenzen des Flach-Clinchens." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-208840.
Повний текст джерелаClinching is one of the most common used mechanical joining processes in automotive industry. Here, two or more overlapping metal sheets are locally formed so that a form- and force-closed joint with diesided protrusion is established. A special type of clinching is the so-called flat-clinching for the production of one-sided planar joints. Within the framework of this thesis, two novel process variants of flat-clinching are developed for enhancing the process limitations of conventional flat-clinching. For increasing the joint strength, a complementary joining element is inserted into the joint. This causes an enlargement of the interlocking, leading to a higher resistance to cross tension loads. Also, the additional material stabilizes the joint and hence improves the resistance to shear load. The second process variant, adhesive flat-clinching, includes the combination of flat-clinching and adhesive bonding. The metal sheets are fixed by flat-clinching and the final joint strength is achieved after the complete curing of the adhesive. This enables a continuous processing of the component and therefore, the process time can be shortened. The development of flat-clinching using complementary joining elements and adhesive flat-clinching is exclusively carried out by using numerical simulation. The knowledge gained from the simulations is subsequently experimentally proven. Also, the joint strength of the novel process variants is experimentally determined
Holsten, Sven. "FEM-unterstützte Parameterstudie des Innengewinde-Fertigungsverfahrens Gewindefurchen." Kassel : Kassel Univ. Press, 2005. http://deposit.d-nb.de/cgi-bin/dokserv?idn=981992331.
Повний текст джерелаChiocchetti, Simone. "High order numerical methods for a unified theory of fluid and solid mechanics." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/346999.
Повний текст джерелаLi, Ziyun. "Haptic Dissection of Deformable Objects using Extended Finite Element Method." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31445.
Повний текст джерелаBeuchler, Sven. "Wavelet preconditioners for the p-version of the fem." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200600607.
Повний текст джерелаCenanovic, Mirza. "Finite element methods on surfaces." Licentiate thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Produktutveckling - Simulering och optimering, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-28424.
Повний текст джерелаDogan, Abdulkadir. "Petrov-Galerkin finite element methods." Thesis, Bangor University, 1997. https://research.bangor.ac.uk/portal/en/theses/petrovgalerkin-finite-element-methods(4d767fc7-4ad1-402a-9e6e-fd440b722406).html.
Повний текст джерелаPalmerini, Claudia. "On the smoothed finite element method in dynamics: the role of critical time step for linear triangular elements." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Знайти повний текст джерелаDamme, Sabine. "Zur Finite-Element-Modellierung des stationären Rollkontakts von Rad und Schiene." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1178280100443-79279.
Повний текст джерелаScope of this work is the preparation of a suitable simulation tool for the numerical investigation of rolling contact phenomena. The main focus lies on the continuum–mechanical formulation of the mechanical field problem of contacting bodies and its numerical solution within the framework of the Finite Element Method. For reducing the numerical effort in rolling contact simulation, induced by the necessity of a very fine discretization within the expected contact area, a relative–kinematical description is utilized. This arbitrary LAGRANGian–EULERian approach is based upon the decomposition of the total motion into a rigid body motion and a superimposed deformation. The derivation of the equation of motion for the contact problem requires the relative–kinematical formulation of the continuum–mechanical fundamental equations, i. e. the balance equations and the constitutive relations. A suitable contact model including the contact of rough surfaces and varying contact boundary conditions is also necessary. The physical embedding into the environment is accomplished by NEUMANN and DIRICHLET boundary conditions. Based upon that foundation the elastomechanics’ equations of motion are derived, which however can not be solved analytically in general. Hence, the equations of motion are transferred into their weak form by the application of the principle of virtual displacements serving for the numerical solution. The implementation of the problem demands for an incremental and discrete formulation of the equations, especially regarding the terms of inertia and the contact terms. Thereby, special attention has to be paid to the distinction between sticking and sliding within the framework of the tangential contact analysis. The numerical solution of the finite elements’ system of equations provides the state of stress, displacement and contact of two bodies in rolling contact. The reliability of the developed algorithms is finally verified by means of meaningful numerical examples for both static contact and for stationary rolling contact, whereby the numerical results coincide well with available analytical reference solutions
Melnikov, Anton. "Strukturzuverlässigkeit durch Frequenzganganalyse mit Finite-Elemente-Methode im Rahmen des Projektes DRESDYN." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-226090.
Повний текст джерелаLau, Sum-hung. "Adaptive FEM preprocessing for electro magnetic field analysis of electric machines /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17505823.
Повний текст джерелаIatridis, Konstantin. "Temperaturoptionen für die Elemente BITO und TORU des FEM-Programms COSA." [S.l.] : Universität Stuttgart , Zentrale Universitätseinrichtung (RUS, UB etc.), 1996. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB6783421.
Повний текст джерелаDamme, Sabine. "Zur Finite-Element-Modellierung des stationären Rollkontakts von Rad und Schiene." Doctoral thesis, Technische Universität Dresden, 2006. https://tud.qucosa.de/id/qucosa%3A24869.
Повний текст джерелаScope of this work is the preparation of a suitable simulation tool for the numerical investigation of rolling contact phenomena. The main focus lies on the continuum–mechanical formulation of the mechanical field problem of contacting bodies and its numerical solution within the framework of the Finite Element Method. For reducing the numerical effort in rolling contact simulation, induced by the necessity of a very fine discretization within the expected contact area, a relative–kinematical description is utilized. This arbitrary LAGRANGian–EULERian approach is based upon the decomposition of the total motion into a rigid body motion and a superimposed deformation. The derivation of the equation of motion for the contact problem requires the relative–kinematical formulation of the continuum–mechanical fundamental equations, i. e. the balance equations and the constitutive relations. A suitable contact model including the contact of rough surfaces and varying contact boundary conditions is also necessary. The physical embedding into the environment is accomplished by NEUMANN and DIRICHLET boundary conditions. Based upon that foundation the elastomechanics’ equations of motion are derived, which however can not be solved analytically in general. Hence, the equations of motion are transferred into their weak form by the application of the principle of virtual displacements serving for the numerical solution. The implementation of the problem demands for an incremental and discrete formulation of the equations, especially regarding the terms of inertia and the contact terms. Thereby, special attention has to be paid to the distinction between sticking and sliding within the framework of the tangential contact analysis. The numerical solution of the finite elements’ system of equations provides the state of stress, displacement and contact of two bodies in rolling contact. The reliability of the developed algorithms is finally verified by means of meaningful numerical examples for both static contact and for stationary rolling contact, whereby the numerical results coincide well with available analytical reference solutions.
Kleiven, Svein. "Finite Element Modeling of the Human Head." Doctoral thesis, KTH, Farkost- och flygteknik, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3347.
Повний текст джерелаQC 20100428
Bedoya, Cervera Jose Julian. "Stent design and arterial mechanics: parameterization tools using the finite element method." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5812.
Повний текст джерелаO, Chol Gyu. "Shape optimization for Two-Dimensional transonic airfoil by using the coupling of FEM and BEM." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-26978.
Повний текст джерелаZeng, Wei. "Advanced Development of Smoothed Finite Element Method (S-FEM) and Its Applications." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439309306.
Повний текст джерелаLins, Rafael Marques. "A posteriori error estimations for the generalized finite element method and modified versions." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-03092015-083839/.
Повний текст джерелаEsta tese investiga dois estimadores de erro a posteriori, baseados na recuperação do gradiente, visando preencher o hiato das estimativas de erro para o Generalized FEM (GFEM) e, sobretudo, suas versões modificadas denominadas Corrected XFEM (C-XFEM) e Stable GFEM (SGFEM). De modo a alcançar este objetivo, primeiramente, breves revisões a respeito do GFEM e suas versões modificadas são apresentadas, onde as principais vantagens atribuídas a cada método são destacadas. Em seguida, alguns importantes conceitos relacionados ao estudo do erro são apresentados. Além disso, algumas contribuições envolvendo estimativas de erro a posteriori para o GFEM são brevemente descritas. Posteriormente, os dois estimadores de erro propostos neste trabalho são abordados focando em problemas da mecânica da fratura elástico linear. O primeiro estimador foi originalmente proposto para o C-XFEM e por este meio é estendido para o âmbito do SGFEM. O segundo é baseado em uma divisão do campo de tensões recuperadas em duas partes distintas: singular e suave. A parte singular é calculada com o auxílio da integral J, enquanto que a suave é calculada a partir da combinação entre as técnicas Superconvergent Patch Recovery (SPR) e Singular Value Decomposition (SVD). Finalmente, vários exemplos numéricos são selecionados para avaliar a robustez dos estimadores de erro considerando diferentes tipos de enriquecimento, versões do GFEM, modos solicitantes e tipos de elemento. Aspectos relevantes tais como índices de efetividade, distribuição do erro e taxas de convergência são usados para descrever os estimadores de erro. As principais contribuições desta tese são: o desenvolvimento de dois eficientes estimadores de erro a posteriori para o GFEM e suas versões modificadas; uma comparação entre o GFEM e suas versões modificadas; a identificação das características positivas de cada estimador de erro e um estudo detalhado sobre a questão dos elementos de mistura.
Wong, S.-W. "Element-by-element methods in transient analysis." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383902.
Повний текст джерелаMekchay, Khamron. "Convergence of adaptive finite element methods." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3216.
Повний текст джерелаThesis research directed by: Mathematics. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Zeng, Yang. "Finite Element Methods for Microelectromechanical Systems." Thesis, Uppsala University, Department of Information Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-110896.
Повний текст джерелаThe stationary Joule heating problem is a crucial multiphysical problem for many microelectromechanical (MEMS) applications. In our paper, we derive a finite element method for this problem and introduce iterative solution-techniques to compute the numerical simulation. Further we construct an adaptive algorithm for mesh refinement based on a posteriori error estimation.Finally, we present two numerical tests: convergences analysis of different iterative methods for distinct materials which are classified by electrical conductivities, and a test of the new adaptive refinement algorithm. All the numerical implementations have been done in MATLAB.
Samvin, David. "Finite Element Methods for Interface Problems." Licentiate thesis, Jönköping University, JTH, Industriell produktutveckling, produktion och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-54570.
Повний текст джерелаDenna avhandling fokuserar på effektiva beräkningsmetoder för flöde i porösa media med sprickor. Två tillvägagångssätt presenteras där sprickan tillåts skära det underliggande finita elementnätet. Sprickans inverkan på flödet tas om hand med hjälp av den underliggande diskretiseringen som tillåter diskontinuiteter. Med andra ord kan flöden modelleras med olika egenskaper; på var sida av sprickan, samt längs sprickan. Metoden tar även hand om instabilitet som uppstår dels på grund av godtyckliga skärningar av bakgrundselementen och dels på grund av olika materialegenskaper. Syftet med denna avhandling är att presentera grunderna för dessa metoder och ge grundläggande matematiska förklaringar.
Chaabane, Nabil. "Immersed and Discontinuous Finite Element Methods." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73194.
Повний текст джерелаPh. D.
Cenanovic, Mirza. "Finite element methods for surface problems." Doctoral thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Produktutveckling, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-35369.
Повний текст джерелаHuang, Yihan. "Extrusion die design using finite element method for sheet and pipe dies." Thesis, Nottingham Trent University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297736.
Повний текст джерелаDostál, Tomáš. "Návrh ražby a primárního ostění tunelu na stavbě vysokorychlostního železničního spojení." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409747.
Повний текст джерелаOf, Günther, Gregory J. Rodin, Olaf Steinbach, and Matthias Taus. "Coupling Methods for Interior Penalty Discontinuous Galerkin Finite Element Methods and Boundary Element Methods." Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-96885.
Повний текст джерелаHuang, Huai Hui. "Simulação da formação de cavacos usando FEM (Finite Element Method) - temperatura e força." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18145/tde-11122007-162007/.
Повний текст джерелаThe distribution of temperature, the deformations and the cutting forces in the cutting zone during chip formation are very important aspects of the process. Therefore they have great influence in results of machining. Tool wear, the precision of the machining operations and the finishing superface are some of these results that affect the economy of the process. This work has the objective of an evaluation offered potentialities for simulating chip formation using FEM (Finite Element Method). Four models with sufficiently different principles are used to exploring the most recent innovations in terms of resources offered by ABAQUS/Explicit software. In the models, WC tools coated TiN was used to machine AISI 4340 steel. The simulations provide a study and detailed examination of temperature distribution, deformations, cutting forces, flow of material and an enormous amount of information that could be useful for the analysis of new processes and optimization of existing processes. Additionally, they open new horizon in the study of the chip formation. The simulations also demonstrate the complexity of the chip formation process, which creates many difficulties for its analysis using based analytical equations in constants. Some comparisons are established with experimental results found in temperature measurements.
Tumonis, Liudas. "Simulation of mechanical behaviour of the electromagnetic railgun by finite element method." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100303_124423-17934.
Повний текст джерелаDisertacijoje baigtinių elementų metodu nagrinėjamas elektromagnetinės šaudyklės (EMŠ) konstrukcinių dalių mechaninis būvis, veikiant dinaminei ap-krovai. Tyrimo objektas yra EMŠ „EMA-3“. Šaudyklės mechaninė dalis sudaryta iš elektrai laidžių bėgių, pritvirtintų prie dielektrinio pagrindo. Tiriama mechani-nio būvio rodiklių priklausomybė nuo apkrovos pobūdžio ir šaudyklės bėgių įtvirtinimo. Šaudyklės mechaninio būvio nustatymas jos darbo metu leistų tiks-liau prognozuoti jos elgseną, pagreitintų projektavimą, tobulinimą ir atpigintų eksploatavimą. Disertacijos tikslas yra skaitiniais metodais aprašyti ir ištirti šau-dyklės mechaninį deformavimą, veikiant dinaminei apkrovai, ištirti mechaninio būvio rodiklių priklausomybes nuo apkrovos parametrų, palyginti skirtingus ap-krovų režimus. Remiantis gautais skaičiavimo rezultatais, siekiama įvertinti šių veiksnių įtaką ir teikti siūlymus režimų patobulinimui. Darbe spręsti keli uždaviniai: sudarytas ir ištirtas „EMA-3“ šaudyklės skaiti-nis baigtinių elementų modelis. Pasiūlytais rodikliais įvertintas šaudyklės mecha-ninis būvis ir palyginta realių apkrovų įtaką bėgių deformavimui. Uždaviniai su-formuluoti atsižvelgiant į esamų modelių ribotumą, į šaudyklės rezonansinę elgseną kritinio greičio aplinkoje ir į tinkamo darbinio režimo parinkimo proble-mą. Disertaciją sudaro įvadas ir keturi skyriai. Įvade apibrėžta tyrimų sritis ir aktualumas, aprašyta mokslo problema, su-formuluotas darbo tikslas ir uždaviniai, paminėti naudoti tyrimo... [toliau žr. visą tekstą]
Karasan, Mustafa Murat. "Residual Stress Analysis Of Riveting Process Using Finite Element Method." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608997/index.pdf.
Повний текст джерелаtheir permanence after installation and their economical advantages. In a riveted joint, it is known that residual stresses are present as a result of the installation process. Furthermore, during the flight of an aircraft, the fuselage is loaded in one cycle and such cycles are repeated throughout the service life. As a result, the panels and the rivets are subjected to fatigue type loading. The integrity of the joint must be maintained against this combination of service loads and the residual stresses. Hence, the riveting process parameters which influence the residual stresses are utmost critical in terms of fatigue life of the hole body. In this study it is aimed to obtain an accurate numerical model of a single-lap riveted joint which is widely used in airframes. 2-D axisymmetrical and 3-D numerical models are generated using commercial finite element code ABAQUS/CAE and subsequent parametric studies are carried out on these models. The Results of both models are compared with those found in the literature. Clearance between hole and rivet shank is selected as the primary parameter to be inspected. The effects of hole clearance on the final residual stress field are examined on 2-D and 3D models. Furthermore, a through the thickness, crack on the inner panel which is initiated after installation is modeled. The crack is perpendicular to the direction of loading. It is placed to the residual tensile stress zone that surrounds the rivet hole. Hence, the effects of residual stresses are also taken into account. For a riveted joint subjected to fatigue loading, such a macroscopic crack could eventually form. In this thesis, stress intensity factors (SIF&rsquo
s) for this crack are calculated for various parameters such as clearance and crack length. These can be utilized in a subsequent fatigue crack growth analysis as the initial values or they can be used in a fracture analysis, to predict unstable crack growth due to overload (i.e. crack linking).
Bernert, Katrin. "Algorithmus zur adaptiven Neuvernetzung des Werkstückes für die FEM-Simulation des Querwalzens." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11244006.
Повний текст джерелаINOUE, NELSON. "IMPLEMENTATION OF A COMPUTER CODE CONSIDERING THE COUPLING OF THE FINITE ELEMENT METHOD (FEM) AND THE BOUNDARY ELEMENT METHOD (BEM)." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1522@1.
Повний текст джерелаO presente trabalho tem como principais objetivos estudar a formulação do método dos elementos de contorno e implementar um programa computacional para análise de tensões de problemas bi-dimensionais (estado plano de deformação e axissimetria) considerando também a possibilidade de acoplamento dos métodos dos elementos de contorno (MEC) e dos elementos finitos (MEF). Dentro deste estudo são abordados as soluções fundamentais para materiais linearmente elásticos, a formulação das integrais no contorno, as técnicas para tratamento de singularidade, a utilização de nós duplos para estudos de canto, etc. Os resultados numéricos obtidos em alguns problemas bi-dimensionais pelos métodos dos elementos de contorno e dos elementos finitos, considerando isoladamente ou acoplados, são comparados mutuamente e com soluções analíticas da teoria da elasticidade linear. Vantagens e desvantagens destes métodos, bem como dificuldades de implementação numérica, são discutidas ao longo deste trabalho.
The main objectives of this work are the study of the boundary element formulation as well as the implementation of computer program for stress analyses of bidimensional problems under axisymmetric or plane strain conditions. The computer program also combines the boundary element method (BEM) with the finite element method (FEM) thus permitting its application to wide range of geotechnical problems. In this study research several mathematical aspects of the boundary element method are reviewed, such as the fundamental solutions for elastic materials, contour integration, singularities, corner problems, etc. The numeric results obtained in some 2D problems the BEM and FEM, in a coupled or isolated form, are compared with analytical solutions provided by classical theory of elasticity. Advantages and shortcomings of both methods, as well as the difficulties in the computer implementation, are also discussed in this work.