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Jin, Jianming Jin, Jianming Geubelle, Philippe H. Goddard, Lynford L. Gong, Songbin Schutt-Ainé, José E. Zhang, Kedi 2018-09-04T20:33:45Z 2018-09-04T20:33:45Z 2020-09-05T09:15:29Z 2018-01-02 2018-05 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. Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2020-05-01 The student, Kedi Zhang, accepted the attached license on 2018-01-02 at 10:44. The student, Kedi Zhang, submitted this Dissertation for approval on 2018-01-02 at 11:05. This Dissertation was approved for publication on 2018-01-02 at 14:14. DSpace SAF Submission Ingestion Package generated from Vireo submission #12002 on 2018-08-31 at 17:16:34 Made available in DSpace on 2018-09-04T20:33:45Z (GMT). No. of bitstreams: 2 ZHANG-DISSERTATION-2018.pdf: 32256174 bytes, checksum: ea0e26002b50757d3bc8465ccc99bd64 (MD5) LICENSE.txt: 4207 bytes, checksum: a820b2a928adee3b7f252c4c62afae53 (MD5) Previous issue date: 2018-01-02 Embargo set by: Seth Robbins for item 107191 Lift date: 2020-09-04T20:34:13Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 107191 Lift date: 2020-09-04T20:37:00Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 107191 Lift date: 2020-09-04T20:42:08Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only Restriction Lifted for Item 107191 on 2020-09-05T09:15:29Z. application/pdf http://hdl.handle.net/2142/101108 en Copyright 2018 Kedi Zhang computational electromagnetics generalized finite element method domain decomposition method hybrid method parallel computing radar cross-section shape optimization large-scale simulation Advanced finite-element techniques for simulation of composite materials and large-scale scattering problems text text Electrical & Computer Eng Electrical & Computer Engr University of Illinois at Urbana-Champaign Dissertation Ph.D.