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Dissertations / Theses on the topic 'Rigid finite element method'

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Published: 4 June 2025

Last updated: 23 June 2025

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1

Davids, William G. "Modeling of rigid pavements : joint shear transfer mechanisms and finite element solution strategies /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/10157.

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2

Bönisch, Sebastian. "Adaptive finite element methods for rigid particulate flow problems." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:16-opus-70622.

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3

DeVries, Mark R. "Vibration of a cantilever beam that slides axially in a rigid frictionless hole." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA241352.

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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, September 1990.<br>Thesis Advisor(s): Salinas, David. "September 1990." Description based on title screen as viewed on December 17, 2009. DTIC Identifier(s): Vibration, sliding friction, guns barrels, cantilever beams, Euler equations, finite element analysis, transformations (mathematics), theses, frictionless holes, holes (openings), recoil. Author(s) subject terms: Cantilever beam, finite element method, axial motion, vibration, transient behavior. Includes bibliographical references (p. 110). Also available in print.

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4

Mello, Frank James. "Weak formulations in analytical dynamics, with applications to multi-rigid-body systems, using time finite elements." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/32854.

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5

Li, Ching-Chang. "Use of iterative techniques for the rigid-viscoplastic finite element analysis." Ohio : Ohio University, 1986. http://www.ohiolink.edu/etd/view.cgi?ohiou1183139974.

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6

Rivera, Alejandro. "Non-Linear Finite Element Method Simulation and Modeling of the Cold and Hot Rolling Processes." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/31035.

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A nonlinear finite element model of the hot and cold rolling processes has been developed for flat rolling stock with rectangular cross section. This model can be used to analyze the flat rolling of cold and hot steel rectangular strips under a series of different parameters, providing the rolling designer with a tool that he can use to understand the behavior of the steel as it flows through the different passes. The models developed, take into account all of the non-linearities present in the rolling problem: material, geometric, boundary, and heat transfer. A coupled thermal-mechanical analysis approach is used to account for the coupling between the mechanical and thermal phenomena resulting from the pressure-dependent thermal contact resistance between the steel slab and the steel rolls. The model predicts the equivalent stress, equivalent plastic strain, maximum strain rate, equivalent total strain, slab temperature increase, increase in roll temperature, strip length increase, slab thickness % reduction (draft), and stripâ s velocity increase, for both the cold and hot rolling processes. The FE model results are an improvement over the results obtained through the classical theory of rolling. The model also demonstrates the role that contact, plastic heat generation and friction generated heat plays in the rolling process. The analysis performed shows that the steel in cold rolling can be accurately modeled using the elastic-plastic (solid Prandtl-Reuss) formulation, with a von Mises yield surface, the Praguer kinematic hardening rule, and the Ramberg-Osgood hardening material model. The FE models also demonstrate that the steel in hot rolling can be modeled using the rigid-viscoplastic (flow Levy-Mises) formulation, with a von Mises yield surface, and Shidaâ s material model for high temperature steel where the flow stress is a function of the strain, strain rate, and the temperature. Other important contributions of this work are the demonstration that in cold rolling, plane sections do not remain plane as the classic theory of rolling assumes. As a consequence, the actual displacements, velocity, and stress distributions in the workpiece are compared to and shown to be an improvement over the distributions derived from the classical theory. Finally, the stress distribution in the rolls during the cold rolling process is found, and shown to be analogous to the stress distribution of the Hertz contact problem.<br>Master of Science

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7

Bönisch, Sebastian [Verfasser], and Rolf [Akademischer Betreuer] Rannacher. "Adaptive Finite Element Methods for Rigid Particulate Flow Problems / Sebastian Bönisch ; Betreuer: Rolf Rannacher." Heidelberg : Universitätsbibliothek Heidelberg, 2006. http://d-nb.info/1178796590/34.

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8

Bryner, Thomas K. "The composite extrusion process." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1182284434.

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9

Roberts, Peter John. "Numerical modelling of single and two phase fluid flow and energy transport in rigid and deforming porous media." Thesis, Swansea University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.644360.

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10

Beegle, David J. "Three-dimensional modeling of rigid pavement." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1176842076.

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11

Heard, William Franklin. "Diagonal and horizontal stiffeners for shear transfer in rigid frame square knees." Master's thesis, Mississippi State : Mississippi State University, 2006. http://library.msstate.edu/etd/show.asp?etd=etd-11092006-214442.

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12

De, Freitas Alves Talita. "Thermomechanical behaviour of bituminous lavers containing rigid inserts for eRoads." Thesis, Ecole centrale de Nantes, 2022. https://tel.archives-ouvertes.fr/tel-03920982.

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En général, quatre facteurs doivent être pris en compte avec précision et simplicité lors de la conception des chaussées souples : le trafic et la charge, les conditions environnementales, les propriétés des matériaux et les critères de défaillance (HUANG, 2004). L'inclusion de technologies de charge de véhicules en mouvement à l'intérieur des infrastructures routières modifie non seulement la disposition commune des couches, mais également la réponse globale de la structure aux sollicitations thermiques et mécaniques. Afin de quantifier l'impact de ces inclusions sur les performances des chaussées, cette étude propose des méthodologies à la fois numériques et expérimentales pour mesurer les évolutions de température, de contraintes et de déformations au sein des routes électrifiées (eRoads). Au moyen de simulations thermo-viscoélastiques transitoires en 2D en utilisant la Méthode des Éléments Finis (MEF), des profils routiers traditionnels et électrifiés ont été soumis aux fluctuations de température quotidiennes et au trafic.L'eRoad étudiée contient des rails électrifiés encastrés dans la couche de roulement bitumineuse, un cas particulièrement intéressant en raison de son exposition directe au trafic et au climat. La réponse des structures a été analysée et comparée à des valeurs admissibles couramment évaluées pour prédire l’endommagement. En laboratoire, un test thermique a été proposé pour évaluer les échantillons eRoad subissant des cycles chauds et froids au moyen de la technique de Corrélation d'Images Numériques (CIN). Les champs de déformation mesurés numériquement et expérimentalement conduisent à la même conclusion : les inserts rigides génèrent des contraintes supplémentaires le long de l'interface de l'unité de chargement et de la couche bitumineuse dues uniquement aux fluctuations quotidiennes de température. Le modèle thermo-viscoélastique proposé et le montage expérimental ont un grand potentiel pour évaluer des profils de chaussée innovants (eRoads inductives et conductrices)<br>In general, four factors need to be accurately and simply accounted for on the design of flexible pavements: traffic and loading, environmental conditions, materials properties and failure criteria (HUANG, 2004). The inclusion of charge-while-drive technologies inside road infrastructures modifies not only the common disposal of layers, but also the overall response of the structure to thermal and mechanical loadings. In order to quantify the impact of these inclusions on the performance of flexible pavements, this study proposes both numerical and experimental methodologies to measure temperature, stress and strain evolutions within electrified roads (eRoads). By means of transient 2-D FEM thermo-viscoelastic simulations, traditional and electrified road profiles were subjected to daily temperature fluctuations and to traffic.The eRoad studied contains electrified rails embedded in the bituminous wearing course, a case of particular interest due to its direct exposure to traffic and climate. The response of the structures was analysed and compared to admissible values commonly assessed to predict distresses. In laboratory, a thermal test was proposed to evaluate eRoad specimens undergoing warm and cold cycles by means of Digital Image Correlation (DIC) technique. The strain fields measured numerically and experimentally lead to the same conclusion: the rigid inserts generate additional strain along the interface of the charging unit and the bituminous layer solely due to daily temperature fluctuations. The thermos-viscoelastic model proposed and the experimental set-up have a great potential to assess innovative pavement profiles (inductive and conductive eRoads)

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13

Rivera, Rojas Alfonso Jose. "Lateral response of stiff column-supported shallow foundations." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100795.

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The mechanisms that control the lateral response of stiff column-supported shallow foundations, resulting from the application of horizontal load on shallow foundations supported by stiff columns, are uncertain. Stiff columns constructed in soft clayey soil have been used to support retaining walls and in such cases, the lateral thrust applied behind these geotechnical structures is a source of horizontal loading. For seismic events, stiff columns constructed in soft clayey soil have been used to support shallow foundations subjected to horizontal load coming from the upper structure of buildings. Due to its practical applications, it has become important to understand the consequences of subjecting a shallow foundation supported by stiff columns to horizontal load by identifying the factors that control the lateral response of such systems. A series of centrifuge tests were carried out to examine the lateral response of stiff column-supported shallow foundations. The experimental trends suggested that the thickness of the coarse-granular mattress placed above the soil-column composite, called the Load Transfer Platform (LTP), controlled the lateral capacity and the overall lateral response of these systems. A numerical study using the finite element method confirmed the experimental trends. A parametric analysis was conducted with the purpose of investigating the influence of different geometry-based and material-based variables in the lateral response of these systems. The results of the parametric analysis further confirmed the importance of the thickness of the LTP in controlling the lateral response. The parametric results also emphasized the contribution of other variables to this lateral response, and these variables included the undrained shear strength of the soft clayey soil around the stiff columns, the stiff column diameter, and the spacing of the stiff columns after they are constructed in the soft clayey soil.<br>Doctor of Philosophy

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14

Hošek, Štěpán. "Návrh konstrukčních úprav pro zmírnění následků předního nárazu automobilu do nedeformovatelné bariéry." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400464.

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There are many collisions on the roads every day. Automotive companies do number of different types of crash-tests to reduce the consequences of these collisions. Crash-tests are supposed to uncover problems of tested vehicles. Then it is possible to propose constructional changes to reduce the consequences of different types of collisions. Indipendent organisations then test productional vehicles according to their standarts and evaluate safety of these vehicles. One of these crash-tests is the small overlap test which is being done by Insurance Institute for Highway Safety. The small overlap test will be the subject of this thesis. Computational modelling of small overlap test is realised for basic variant and for variants with changes. There is also comparison of basic variant and variants with changes.

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15

Viktora, Luboš. "Návrh roštu výtahového stroje a vodítek." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230031.

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This thesis deals with the control of grid of lift machine and rigid hanging of ropes for elevator with a capacity of 675 kg. The main focus is strength analysis using finite element method. Furthermore, a calculation was performed also for anchoring of slide-ways and strength check was done according to standard ČSN EN 81-1. The thesis contains also the assembly drawing of grid of lift machine and it was executed in cooperation with LIFTMONT CZ s.r.o.

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16

El, Feghali Stéphanie. "Nouvelle formulation monolithique en élément finis stabilisés pour l'interaction fluide-structure." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00743488.

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L'Interaction Fluide-Structure (IFS) décrit une classe très générale de problème physique, ce qui explique la nécessité de développer une méthode numérique capable de simuler le problème FSI. Pour cette raison, un solveur IFS est développé qui peut traiter un écoulement de fluide incompressible en interaction avec des structures différente: élastique ou rigide. Dans cet aspect, le solveur peut couvrir une large gamme d'applications.La méthode proposée est développée dans le cadre d'une formulation monolithique dans un contexte Eulérien. Cette méthode consiste à considérer un seul maillage et résoudre un seul système d'équations avec des propriétés matérielles différentes. La fonction distance permet de définir la position et l'interface de tous les objets à l'intérieur du domaine et de fournir les propriétés physiques pour chaque sous-domaine. L'adaptation de maillage anisotrope basé sur la variation de la fonction distance est ensuite appliquée pour assurer une capture précise des discontinuités à l'interface fluide-solide.La formulation monolithique est assurée par l'ajout d'un tenseur supplémentaire dans les équations de Navier-Stokes. Ce tenseur provient de la présence de la structure dans le fluide. Le système est résolu en utilisant une méthode élément fini et stabilisé suivant la formulation variationnelle multiéchelle. Cette formulation consiste à décomposer les champs de vitesse et pression en grande et petite échelles. La particularité de l'approche proposée réside dans l'enrichissement du tenseur de l'extra contraint.La première application est la simulation IFS avec un corps rigide. Le corps rigide est décrit en imposant une valeur nul du tenseur des déformations, et le mouvement est obtenu par la résolution du mouvement de corps rigide. Nous évaluons le comportement et la précision de la formulation proposée dans la simulation des exemples 2D et 3D. Les résultats sont comparés avec la littérature et montrent que la méthode développée est stable et précise.La seconde application est la simulation IFS avec un corps élastique. Dans ce cas, une équation supplémentaire est ajoutée au système précédent qui permet de résoudre le champ de déplacement. Et la contrainte de rigidité est remplacée par la loi de comportement du corps élastique. La déformation et le mouvement du corps élastique sont réalisés en résolvant l'équation de convection de la Level-Set. Nous illustrons la flexibilité de la formulation proposée par des exemples 2D.

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17

Reis, Marcelo Campos Junqueira. "Análise não linear geométrica de pórticos planos considerando ligações semirrígidas elastoplásticas." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-06082012-082337/.

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Neste trabalho foi implementada uma técnica para considerar ligações semirrígidas elastoplásticas para a análise não linear geométrica de pórticos planos. As ligações semirrígidas foram consideradas com o comportamento elastoplástico multilinear e modeladas via o Método dos Elementos Finitos (MEF). Esta técnica foi acoplada ao programa AcadFrame, baseado no Método dos Elementos Finitos Posicional (MEFP) para a análise não linear geométrica de pórticos planos e treliças planas. O acoplamento numérico foi realizado através de uma formulação algébrica em que a matriz de rigidez das ligações semirrígidas elastoplásticas e as forças internas das ligações são somadas à matriz e ao vetor de forças internas da estrutura a cada iteração no processo de Newton-Raphson. Conceitos de álgebra linear e tensorial, dinâmica não linear, deformação, tensão, princípios variacionais e métodos numéricos são necessários para este propósito. Simular-se-ão diversos exemplos de ligações semirrígidas de estruturas metálicas e de concreto pré-moldado para a verificação das implementações realizadas. O trabalho permite a análise não linear geométrica de pórticos planos considerando as ligações semirrígidas elastoplásticas.<br>This work presents a technique to consider elastoplastic semi-rigid connections for geometric nonlinear analysis of plane frames. The connections were considered semi-rigid with elastoplastic behavior and modeled by The Finite Element Method (FEM). This technique was coupled to AcadFrame program, based on the Finite Element Method for geometric nonlinear analysis of plane frames and trusses flat. The numerical coupling is made by an algebraic formulation where, at each iteration of the Newton-Raphson process, the connections stiffness matrix and elastoplastic internal forces of are added to the Hessian matrix and the internal force vector of the structure. Concepts of linear and tensor algebra, non-linear strain, stress, variational principles and numerical methods are needed for this purpose. Several examples with semi-rigid connections are solved to verify the proosed formulation and performed implementations. This study allows geometric nonlinear analysis of plane frames considering elastoplastic semi-rigid connections, as steel and precast concrete structures.

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18

Kang, David Sung-Soo. "Hybrid stress finite element method." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/14973.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1986.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO<br>Bibliography: leaves 257-264.<br>by David Sung-Soo Kang.<br>Ph.D.

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Uslu, Cafer Harun. "3-d Finite Element Analysis Of Semi-rigid Steel Connections." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610835/index.pdf.

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Two types of connection are generally considered in the design of steel structures in practice. These are classified as completely rigid (moment) and simple (shear) connections. In theory, completely rigid connections can not undergo rotation and simple connections can not transfer moment. However, in reality rigid connections have a relative flexibility which makes them to rotate and simple connections have some reserve capacity to transfer moments. In many modern design specifications, this fact is realized and another type which is called partially restrained or semi-rigid connection is introduced. These types of connections have got the transfer of some beam moment to column together with shear. However, there is a lack of information on the amount of moment transferred and rotation of connection during the action of the moment transfer. The only way to quantify the moment and rotation of the partially restrained connections is to draw momentrotation curves. Nevertheless, drawing such curves requires great amount of expenses for experiments. Taking these into account, the use of finite elements with the help of increased computational power is one way to obtain moment-rotation curves of connections. Available test results guides the finite element analysis for justifications. So these analyses can be further implemented into design functions. This thesis is intended to conduct 3-D non-linear finite element analyses to compliment with tests results for different types of semi-rigid connections with angles and compare them with mathematical models developed by different researchers.

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20

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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21

Sevilla, Cárdenas Rubén. "NURBS-Enhanced Finite Element Method (NEFEM)." Doctoral thesis, Universitat Politècnica de Catalunya, 2009. http://hdl.handle.net/10803/5857.

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Aquesta tesi proposa una millora del clàssic mètode dels elements finits (finite element method, FEM) per a un tractament eficient de dominis amb contorns corbs: el denominat NURBS-enhanced finite element method (NEFEM). Aquesta millora permet descriure de manera exacta la geometría mitjançant la seva representació del contorn CAD amb non-uniform rational B-splines (NURBS), mentre que la solució s'aproxima amb la interpolació polinòmica estàndard. Per tant, en la major part del domini, la interpolació i la integració numèrica són estàndard, retenint les propietats de convergència clàssiques del FEM i facilitant l'acoblament amb els elements interiors. Només es requereixen estratègies específiques per realitzar la interpolació i la integració numèrica en elements afectats per la descripció del contorn mitjançant NURBS.<br/><br/>La implementació i aplicació de NEFEM a problemes que requereixen una descripció acurada del contorn són, també, objectius prioritaris d'aquesta tesi. Per exemple, la solució numèrica de les equacions de Maxwell és molt sensible a la descripció geomètrica. Es presenta l'aplicació de NEFEM a problemes d'scattering d'ones electromagnètiques amb una formulació de Galerkin discontinu. S'investiga l'habilitat de NEFEM per obtenir solucions precises amb malles grolleres i aproximacions d'alt ordre, i s'exploren les possibilitats de les anomenades malles NEFEM, amb elements que contenen singularitats dintre d'una cara o aresta d'un element. Utilitzant NEFEM, la mida de la malla no està controlada per la complexitat de la geometria. Això implica una dràstica diferència en la mida dels elements i, per tant, suposa un gran estalvi tant des del punt de vista de requeriments de memòria com de cost computacional. Per tant, NEFEM és una eina poderosa per la simulació de problemes tridimensionals a gran escala amb geometries complexes. D'altra banda, la simulació de problemes d'scattering d'ones electromagnètiques requereix mecanismes per aconseguir una absorció eficient de les ones scattered. En aquesta tesi es discuteixen, optimitzen i comparen dues tècniques en el context de mètodes de Galerkin discontinu amb aproximacions d'alt ordre.<br/><br/>La resolució numèrica de les equacions d'Euler de la dinàmica de gasos és també molt sensible a la representació geomètrica. Quan es considera una formulació de Galerkin discontinu i elements isoparamètrics lineals, una producció espúria d'entropia pot evitar la convergència cap a la solució correcta. Amb NEFEM, l'acurada imposició de la condició de contorn en contorns impenetrables proporciona resultats precisos inclús amb una aproximació lineal de la solució. A més, la representació exacta del contorn permet una imposició adequada de les condicions de contorn amb malles grolleres i graus d'interpolació alts. Una propietat atractiva de la implementació proposada és que moltes de les rutines usuals en un codi d'elements finits poden ser aprofitades, per exemple rutines per realitzar el càlcul de les matrius elementals, assemblatge, etc. Només és necessari implementar noves rutines per calcular les quadratures numèriques en elements corbs i emmagatzemar el valor de les funciones de forma en els punts d'integració. S'han proposat vàries tècniques d'elements finits corbs a la literatura. En aquesta tesi, es compara NEFEM amb altres tècniques populars d'elements finits corbs (isoparamètics, cartesians i p-FEM), des de tres punts de vista diferents: aspectes teòrics, implementació i eficiència numèrica. En els exemples numèrics, NEFEM és, com a mínim, un ordre de magnitud més precís comparat amb altres tècniques. A més, per una precisió desitjada NEFEM és també més eficient: necessita un 50% dels graus de llibertat que fan servir els elements isoparamètrics o p-FEM per aconseguir la mateixa precisió. Per tant, l'ús de NEFEM és altament recomanable en presència de contorns corbs i/o quan el contorn té detalls geomètrics complexes.<br>This thesis proposes an improvement of the classical finite element method (FEM) for an efficient treatment of curved boundaries: the NURBSenhanced FEM (NEFEM). It is able to exactly represent the geometry by means of the usual CAD boundary representation with non-uniform rational Bsplines (NURBS), while the solution is approximated with a standard piecewise polynomial interpolation. Therefore, in the vast majority of the domain, interpolation and numerical integration are standard, preserving the classical finite element (FE) convergence properties, and allowing a seamless coupling with standard FEs on the domain interior. Specifically designed polynomial interpolation and numerical integration are designed only for those elements affected by the NURBS boundary representation.<br/><br/>The implementation and application of NEFEM to problems demanding an accurate boundary representation are also primary goals of this thesis. For instance, the numerical solution of Maxwell's equations is highly sensitive to geometry description. The application of NEFEM to electromagnetic scattering problems using a discontinuous Galerkin formulation is presented. The ability of NEFEM to compute an accurate solution with coarse meshes and high-order approximations is investigated, and the possibilities of NEFEM meshes, with elements containing edge or corner singularities, are explored. With NEFEM, the mesh size is no longer subsidiary to geometry complexity, and depends only on the accuracy requirements on the solution, whereas standard FEs require mesh refinement to properly capture the geometry. This implies a drastic difference in mesh size that results in drastic memory savings, and also important savings in computational cost. Thus, NEFEM is a powerful tool for large-scale scattering simulations with complex geometries in three dimensions. Another key issue in the numerical solution of electromagnetic scattering problems is using a mechanism to perform the absorption of outgoing waves. Two perfectly matched layers are discussed, optimized and compared in a high-order discontinuous Galerkin framework.<br/><br/>The numerical solution of Euler equations of gas dynamics is also very sensitive to geometry description. Using a discontinuous Galerkin formulation and linear isoparametric elements, a spurious entropy production may prevent convergence to the correct solution. With NEFEM, the exact imposition of the solid wall boundary condition provides accurate results even with a linear approximation of the solution. Furthermore, the exact boundary representation allows using coarse meshes, but ensuring the proper implementation of the solid wall boundary condition. An attractive feature of the proposed implementation is that the usual routines of a standard FE code can be directly used, namely routines for the computation of elemental matrices and vectors, assembly, etc. It is only necessary to implement new routines for the computation of numerical quadratures in curved elements and to store the value of shape functions at integration points. <br/><br/>Several curved FE techniques have been proposed in the literature. In this thesis, NEFEM is compared with some popular curved FE techniques (namely isoparametric FEs, cartesian FEs and p-FEM), from three different perspectives: theoretical aspects, implementation and performance. In every example shown, NEFEM is at least one order of magnitude more accurate compared to other techniques. Moreover, for a desired accuracy NEFEM is also computationally more efficient. In some examples, NEFEM needs only 50% of the number of degrees of freedom required by isoparametric FEs or p-FEM. Thus, the use of NEFEM is strongly recommended in the presence of curved boundaries and/or when the boundary of the domain has complex geometric details.

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Valivarthi, Mohan Varma, and Hema Chandra Babu Muthyala. "A Finite Element Time Relaxation Method." Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-17728.

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In our project we discuss a finite element time-relaxation method for high Reynolds number flows. The key idea consists of using local projections on polynomials defined on macro element of each pair of two elements sharing a face. We give the formulation for the scalar convection–diffusion equation and a numerical illustration.

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23

Li, Ching-Chang. "Use of iterative technologies for the rigid-viscoplastic finite element analysis." Ohio University / OhioLINK, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1183139974.

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24

梁耀華 and Yew-wah Leung. "Finite element solution on microcomputers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31209300.

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Leung, Yew-wah. "Finite element solution on microcomputers /." [Hong Kong] : University of Hong Kong, 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12754948.

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26

Müller, Björn. "Parallel Finite Element Method with FEAP 8.2." Darmstadt TU, Fachgebiet Numerische Berechnungsverfahren im Maschinenbau, 2009. http://tuprints.ulb.tu-darmstadt.de/1336/.

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27

Zhang, Lin. "Generalized finite element method for multiscale analysis." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/1141.

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This dissertation describes a new version of the Generalized Finite Element Method (GFEM), which is well suited for problems set in domains with a large number of internal features (e.g. voids, inclusions, etc.), which are practically impossible to solve using the standard FEM. The main idea is to employ the mesh-based handbook functions which are solutions of boundary value problems in domains extracted from vertex patches of the employed mesh and are pasted into the global approximation by the Partition of Unity Method (PUM). It is shown that the p-version of the Generalized FEM using mesh-based handbook functions is capable of achieving very high accuracy. It is also analyzed that the effect of the main factors affecting the accuracy of the method namely: (a) The data and the buffer included in the handbook domains, and (b) The accuracy of the numerical construction of the handbook functions. The robustness of the method is illustrated by several model problems defined in domains with a large number of closely spaced voids and/or inclusions with various shapes, including the heat conduction problem defined on domains with porous media and/or a real composite material.

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28

Vu, Thu Hang. "Enhancing the scaled boundary finite element method." University of Western Australia. School of Civil and Resource Engineering, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0068.

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[Truncated abstract] The scaled boundary finite element method is a novel computational method developed by Wolf and Song which reduces partial differential equations to a set of ordinary linear differential equations. The method, which is semi-analytical, is suitable for solving linear elliptic, parabolic and hyperbolic partial differential equations. The method has proved to be very efficient in solving various types of problems, including problems of potential flow and diffusion. The method out performs the finite element method when solving unbounded domain problems and problems involving stress singularities and discontinuities. The scaled boundary finite element method involves solution of a quadratic eigenproblem, the computational expense of which increases rapidly as the number of degrees of freedom increases. Consequently, to a greater extent than the finite element method, it is desirable to obtain solutions at a specified level of accuracy while using the minimum number of degrees of freedom necessary. In previous work, no systematic study had been performed so far into the use of elements of higher order, and no consideration made of p adaptivity. . . The primal problem is solved normally using the basic scaled boundary finite element method. The dual problem is solved by the new technique using the fundamental solution. A guaranteed upper error bound based on the Cauchy-Schwarz inequality is derived. A iv goal-oriented p-hierarchical adaptive procedure is proposed and implemented efficiently in the scaled boundary finite element method.

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29

Davidsson, 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.

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In this essay we present the Sobolev spaces and some basic properties of them. The Sobolev spaces serve as a theoretical framework for studying solutions to partial differential equations. The finite element method is presented which is a numerical method for solving partial differential equations.

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30

Pack, Peter Michael Walter. "The finite element method in underwater acoustics." Thesis, University of Southampton, 1986. https://eprints.soton.ac.uk/52298/.

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A Finite Element Method (FEM) is developed to calculate rotationally symmetric acoustic propagation over short range intervals (0-5 km) in shallow oceans (0-200 m deep) at low frequencies (0-50 Hz). The method allows full two-way wave propagation in range dependent environments and includes coupling to a full elastic seabed. Numerical results from a computer program are presented for propagation upslope, downslope, over seamounts and across trenches in the seabed. The seabed is modelled as a pressure release surface, a fluid halfspace and an elastic, solid halfspace and the implications of each type of model are discussed. The halfspaces, being represented by a new set of infinite elements, are modelled without truncation. The results are presented primarily as plots of transmission loss against range for a fixed depth receiver. Subsidiary results show the effect of depth averaging the receiver location, and extract mode amplitude data to reveal the strength of mode coupling and backscatter in different environments.

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31

Liu, Yunshan. "P-adaptive hybrid/mixed finite element method /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487950153602937.

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32

Lu, Chuan. "Generalized finite element method for electromagnetic analysis." Diss., Connect to online resource - MSU authorized users, 2008.

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Thesis (Ph. D.)--Michigan State University. Electrical and Computer Engineering, 2008.<br>Title from PDF t.p. (viewed on Apr. 8, 2009) Includes bibliographical references (p. 148-153). Also issued in print.

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33

Gundu, Krishna Mohan. "hp-Finite Element Method for Photonics Applications." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195940.

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A hp-finite element method is implemented to numerically study the modes of waveguides with two dimensional cross-section and to compute electromagnetic scattering from three dimensional objects. A method to control the chromatic dispersion properties of photonic crystal fibers using the selective hole filling technique is proposed. The method is based on a single hole-size fiber geometry, and uses an appropriate index-matching liquid to modify the effective size of the filled holes. The dependence of dispersion properties of the fiber on the design parameters such as the refractive index of the liquid, lattice constant and hole diameter are studied numerically. It is shown that very small dispersion values between 0±0.5ps/nm-km can be achieved over a bandwidth of 430-510nm in the communication wavelength region of 1300-1900nm. Three such designs are proposed with air hole diameters in the range 1.5-2.0μm. A novel multi-core fiber design strategy for obtaining a at in-phase supermode that optimizes utilization of the active medium inversion in the multiple cores is proposed. The spatially at supermode is achieved by engineering the fiber so that the total mutual coupling between neighboring active cores is equal. Different designs suitable for different fabrication processes such as stack-and-draw and drilling are proposed. An important improvement over previous methods is the design simplicity and better tolerance to perturbations. The optimal implementation of perfectly matched layer (PML) in terms of minimizing the computational overhead it introduces is studied. In one dimension it is shown that PML implementation with a single cell and a high order finite element produces minimal overhead. Estimates of optimal cell size and optimal finite element degree are given. Based on the single cell implementation of PML in three dimensions, field enhancement in metallic bowties is computed.

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34

Olivier, Albertus Hendrik. "Object-oriented finite element framework." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52971.

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Thesis (MScEng)--Stellenbosch University, 2002.<br>ENGLISH ABSTRACT: The role of the computer has changed from a calculation tool to a tool that supports human thinking. In this thesis fundamental aspects of the Finite Element method are mapped to an object model with a well defined structure which provides for local and distributed analysis work. To achieve this the following was investigated: • An object-oriented framework for the Finite Element analysis method • An associated graphical user interface that enables the user to create and modify Finite Element models in an effective way • Requirements for the sharing of analysis information in a communication network Proposed solutions are implemented in a pilot application which indicates their potential.<br>AFRIKAANSE OPSOMMING: Die rol van die rekenaar het verander vanaf 'n gereedskapstuk wat berekening doen na 'n gereedskapstuk wat menslike denke ondersteun. In hierdie tesis word die fundamentele aspekte van die Eindige Element metode oorgedra na 'n objek model met 'n goed gedefinieerde struktuur wat lokale en verspreide analisering werk ondersteun. Om dit te bereik is die volgende ondesoek: • 'n Objek orienteerde raamwerk vir die Eindige Element metode • 'n Geassosieerde grafiese raamwerk wat die gebruiker in staat stelom objekte te skep en te verander • Vereistes vir die deel van analise inligting in 'n kommunikasie netwerk Die voorgestelde oplossing is geimplimenteer in 'n loodsimplementering wat die voordele van die benadering uitlig.

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35

Xiao, Dong Wen. "Efficiency analysis on element decomposition method for stochastic finite element analysis." Thesis, University of Macau, 2000. http://umaclib3.umac.mo/record=b1636334.

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36

Irfanoglu, Bulent. "Boundary Element-finite Element Acoustic Analysis Of Coupled Domains." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605360/index.pdf.

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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.

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37

Perry, William H. "Finite element analysis of polymer flows." Ohio : Ohio University, 1985. http://www.ohiolink.edu/etd/view.cgi?ohiou1184072781.

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38

Ayers, Christopher Lee. "Concurrent processing of finite element calculations." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/13072.

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39

Heinrich, Bernd, and Beate Jung. "The Fourier-finite-element method with Nitsche-mortaring." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200601493.

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The paper deals with a combination of the Fourier-finite-element method with the Nitsche-finite-element method (as a mortar method). The approach is applied to the Dirichlet problem of the Poisson equation in three-dimensional axisymmetric domains $\widehat\Omega$ with non-axisymmetric data. The approximating Fourier method yields a splitting of the 3D-problem into 2D-problems. For solving the 2D-problems on the meridian plane $\Omega_a$, the Nitsche-finite-element method with non-matching meshes is applied. Some important properties of the approximation scheme are derived and the rate of convergence in some $H^1$-like norm is proved to be of the type ${\mathcal O}(h+N^{-1})$ ($h$: mesh size on $\Omega_a$, $N$: length of the Fourier sum) in case of a regular solution of the boundary value problem. Finally, some numerical results are presented.

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40

Starkloff, Hans-Jörg. "Stochastic finite element method with simple random elements." Universitätsbibliothek Chemnitz, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200800596.

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We propose a variant of the stochastic finite element method, where the random elements occuring in the problem formulation are approximated by simple random elements, i.e. random elements with only a finite number of possible values.

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41

Ahlbert, Gabriella. "Method Evaluation of Global-Local Finite Element Analysis." Thesis, Linköpings universitet, Hållfasthetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78103.

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When doing finite element analysis upon the structure of Saab’s aeroplanes a coarse global model of mainly shell elements is used to determine the load distribution for sizing the structure. At some parts of the aeroplane it is however desirable to implement a more detailed analysis. These areas are usually modelled with solid elements; the problem of connecting the fine local solid elements to the coarse global model will shell elements then arises. This master thesis is preformed to investigate possible Global-Local methods to use for the structural analysis on Gripen. First a literature study of current methods on the market is made, thereafter a few methods are implemented on a generic test structure and later on also tested on a real detail of Gripen VU. The methods tested in this thesis are Mesh refinement in HyperWorks, RBE3 in HyperWorks, Glue in MSC Patran/Nastran and DMIG in MSC Nastran. The software is however not evaluated in this thesis, and a further investigation is recommended to find the most fitting software for this purpose. All analysis are performed with linear assumptions. Mesh refinement is an integrated technique where the elements are gradually decreasing in size. Per definition, this technique cannot handle gaps, but it has almost identical results to the fine reference model. RBE3 is a type of rigid body elements with zero stiffness, and is used as an interface element. RBE3 is possible to use to connect both Shell-To-Shell and Shell-To-Solid, and can handle offsets and gaps in the boundary between the global and local model. Glue is a contact definition and is also available in other software under other names. The global respectively the local model is defined as contact bodies and a contact table is used to control the coupling. Glue works for both Shell-To-Shell and Shell-To-Solid couplings, but has problem dealing with offsets and gaps in the boundary between the global and local model. DMIG is a superelement technique where the global model is divided into smaller sub-models which are mathematically connected. DMIG is only possible to use when the nodes on the boundary on the local model have the same position as the nodes at the boundary of the global model. Thus, it is not possible to only use DMIG as a Global-Local method, but can advantageously be combined with other methods. The results indicate that the preferable method to use for Global-Local analysis is RBE3. To decrease the size of the files and demand of computational power, RBE3 can be combined with a superelement technique, for example DMIG. Finally, it is important to consider the size of the local model. There will inevitably be boundary effect when performing a Global-Local analysis of the suggested type, and it is therefore important to make the local model big enough so that the boundary effects have faded before reaching the area of interest.

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42

Ali, Hassan O. "Near-field computation using the finite element method." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ26122.pdf.

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43

Parvini, Mehdi. "Pavement deflection analysis using stochastic finite element method." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0014/NQ42757.pdf.

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44

Durrani, Jawad Nadeem. "Dynamics of pipelines with a finite element method." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ65153.pdf.

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45

Parvini, Mehdi. "Pavement deflection analysis using stochastic finite element method /." *McMaster only, 1997.

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46

Savchuk, Tatyana. "The multiscale finite element method for elliptic problems." Ann Arbor, Mich. : ProQuest, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3245025.

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Thesis (Ph. D. in Applied Mathematics)--Southern Methodist University, 2007.<br>Title from PDF title page (viewed Mar. 18, 2008). Source: Dissertation Abstracts International, Volume: 67-12, Section: B, page: 7120. Adviser: Zhangxin (John) Chen. Includes bibliographical references.

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47

Dewasurendra, Lohitha. "A finite element method for ring rolling processes." Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1175098096.

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48

Druma, Adriana M. "Analysis of carbon foams by finite element method." Ohio : Ohio University, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1177611967.

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49

Balland, Philippe. "The solenoidal finite element method and reservoir simulation." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260727.

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50

Wong, Sze-chun, and 黃仕進. "Two level finite element method for structural analysis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B30425918.

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