Advanced finite-element techniques for simulation of composite materials and large-scale scattering problems

Zhang, Kedi

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https://hdl.handle.net/2142/101108 Copy

Description

Title

Advanced finite-element techniques for simulation of composite materials and large-scale scattering problems

Author(s)

Zhang, Kedi

Issue Date

2018-01-02

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

Jin, Jianming

Doctoral Committee Chair(s)

Jin, Jianming

Committee Member(s)

• Geubelle, Philippe H.
• Goddard, Lynford L.
• Gong, Songbin
• Schutt-Ainé, José E.

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• computational electromagnetics
• generalized finite element method
• domain decomposition method
• hybrid method
• parallel computing
• radar cross-section
• shape optimization
• large-scale simulation

Abstract

This dissertation aims at developing sophisticated finite-element based numerical algorithms for efficient electromagnetic modeling and design of composite materials, fast frequency-domain scattering analysis of electrically large problems on massive parallelized computers, and efficient broadband analysis of resonant waveguide structures. To these ends, first, an interface-enriched generalized finite-element method (IGFEM) is introduced for electromagnetic analysis of heterogeneous materials. To avoid using conformal meshes, the method assigns generalized degrees of freedom at material interfaces to capture the discontinuities of the field and its derivatives, and maintains the same level of solution accuracy and computational complexity as the standard FEM based on conformal meshes. The fixed mesh nature combined with an analytical sensitivity analysis significantly reduces the computational cost in gradient-based shape optimization. Second, an efficient parallelization strategy is proposed for the domain decomposition based dual-primal finite-element tearing and interconnecting (FETI-DP) algorithm. Load balancing, global, neighboring, inter-processor communication minimization, and preconditioning techniques are adopted to improve the computational and parallel efficiency. An inhomogeneous truncation boundary condition is presented to enable the FETI-DP simulation of a stratified medium. The parallel FETI-DP algorithm is also combined with a fast near- to far-field transformation and a linear interpolation technique for efficient vectorial field imaging of electrically large objects. Finally, a hybrid technique that consists of the time- and frequency-domain computations and model-order reduction strategy is developed for the efficient simulations of resonant waveguide structures. Numerous results are presented to demonstrate the accuracy, efficiency, and capability of the proposed methods.

Graduation Semester

2018-05

Type of Resource

text

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http://hdl.handle.net/2142/101108

Copyright and License Information

Copyright 2018 Kedi Zhang

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