Investigation of stability and accuracy of high order generalized finite element methods

Li, Haoyang

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https://hdl.handle.net/2142/49379 Copy

Description

Title

Investigation of stability and accuracy of high order generalized finite element methods

Author(s)

Li, Haoyang

Issue Date

2014-05-30T16:41:01Z

Director of Research (if dissertation) or Advisor (if thesis)

Duarte, C. Armando

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Date of Ingest

2014-05-30T16:41:01Z

Keyword(s)

• Generalized Finite Element Method (GFEM)
• stable generalized finite element method
• convergence analysis
• conditioning analysis
• high order
• polynomial enrichment

Abstract

The Generalized Finite Element methods (GFEMs) is a family of discretization methods which are based on the partition of unity (PoU) concept and are able to provide users with flexibility in choosing enrichments to approximate the target problem. The quality of the resulting approximation can be judged by the accuracy and its convergence rate, the conditioning and its growth rate. A major type of GFEM enrichment is the polynomial enrichment. Based on that, several modified versions of enrichments can be formulated and adopted in the simulation yielding different approximation behaviors in terms of accuracy and conditioning. By solving a one-dimensional problem and a two-dimensional problem, this report compares the numerical behaviors for different discretization methods including p-Lagrange FEM, p-hierarchical FEM, GFEM, stable GFEM (SGFEM) which is a recently proposed method with improved conditioning, and a number of variations on the GFEM and SGFEM. Other aspects considered are the linear dependency (LD) issue, the effect of mesh perturbation, and the factorization time. They are also presented to provide the reader with a broader knowledge of GFEMs.

Graduation Semester

2014-05

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http://hdl.handle.net/2142/49379

Copyright and License Information

Copyright 2014 Haoyang Li

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