Sökning: "finite element method"

Visar resultat 1 - 5 av 789 avhandlingar innehållade orden finite element method.

1. 1. On failure modelling in finite element analysis : material imperfections and element erosion

   Författare :Mattias Unosson; Larsgunnar Nilsson; Kjell Simonsson; Lars Olovsson; Anders Eriksson; Linköpings universitet; []
   Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finite element method; element erosion; material failure; material imperfections; crack-tip; Solid mechanics; Fastkroppsmekanik;

   Sammanfattning : This dissertation concerns failure modelling with material imperfections and element erosion in finite element analyses. The aim has been to improve the element erosion technique, which is simple to use and implement and also computationally inexpensive. LÄS MER

3. 2. Modelling Alternative Load Paths in Platform-Framed CLT Buildings : A Finite Element Approach

   Författare :Johannes Albert Josef Huber; Mats Ekevad; Ulf Arne Girhammar; Sven Berg; Sigurdur Ormarsson; Luleå tekniska universitet; []
   Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; timber; robustness; finite element method; alternative load paths; disproportionate collapse; Träteknik; Wood Science and Engineering;

   Sammanfattning : Timber has become more popular as a construction material during recent years. Engineered wood products, such as glued laminated timber and cross-laminated timber, have enabled the construction of multi-storey buildings. Tall buildings with many occupants need to resist a disproportional collapse in case of unexpected exposures, e.g. LÄS MER

4. 3. Adaptive Finite Element Methods for Optimal Control Problems

   Författare :Karin Kraft; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; discontinuous Galerkin method; optimal control; a posteriori error estimate; dual weighted residual; adaptive; multilevel algorithm; Newton method; control constraint; variational inequality; vehicle dynamics.; dual weighted residual;

   Sammanfattning : In this thesis we study the numerical solution of optimal control problems. The problems considered consist of a system of differential equations, the state equations, which are governed by a control variable. The goal is to determine the states and controls which minimize a given cost functional. LÄS MER

5. 4. A hybrid finite element method for electromagnetics with applications in time-domain

   Författare :DAVID DEGERFELDT; Chalmers University of Technology; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nitsche s method; antenna arrays; NASA almond; edge elements; scattering; explicit-implicit time-stepping; Maxwell s equations; Finite Element Method; mass lumping; stability analysis; Finite-Differences Time-Domain; periodic structures; shape and material optimization;

   Sammanfattning : In this thesis, a new hybrid method that combines the Finite Element Method (FEM) with the Finite-Difference in Time-Domain (FDTD) method is presented. Tetrahedrons in the unstructured FEM region are connected directly to thehexahedrons in the structured FDTD region. LÄS MER

7. 5. Adaptive Finite Element Procedures in Structural Dynamics

   Författare :Xiangdong Li; Chalmers University of Technology; []
   Nyckelord :finite element; h-adaptivity; Newmark method; structural dynamics; space-time; a posteriori; superconvergent patch recovery; postprocessing; automatic time-stepping; semidiscretization; error estimation; discontinuous Galerkin;

   Sammanfattning : This thesis deals with a posteriori error estimation and adaptivity in finite element procedures for the analysis of structural dynamic problems. First, error estimation and adaptivity for the Newmark time integration method are studied. LÄS MER