Analysis of electromagnetic scattering problems with the finite element method

Yılmaz, A. Egemen


Analysis of photonic-crystal problems with MLFMA and approximate Schur preconditioners
Ergül, Özgür Salih; Kilinç, Seçil; Sarıtaş, Serkan (2009-07-23)
We consider fast and accurate solutions of electromagnetics problems involving three-dimensional photonic crystals (PhCs). Problems are formulated with the combined tangential formulation (CTF) and the electric and magnetic current combined-field integral equation (JMCFIE) discretized with the Rao-Wilton-Glisson functions. Matrix equations are solved iteratively by the multilevel fast multipole algorithm. Since PhC problems are difficult to solve iteratively, robust preconditioning techniques are required t...
Analysis of RC walls with a mixed formulation frame finite element
Sarıtaş, Afşin (2013-10-01)
This paper presents a mixed formulation frame element with the assumptions of the Timoshenko shear beam theory for displacement field and that accounts for interaction between shear and normal stress at material level. Nonlinear response of the element is obtained by integration of section response, which in turn is obtained by integration of material response. Satisfaction of transverse equilibrium equations at section includes the interaction between concrete and transverse reinforcing steel. A 3d plastic...
Analysis of Dielectric Photonic-Crystal Problems With MLFMA and Schur-Complement Preconditioners
Ergül, Özgür Salih; Gurel, Levent (Institute of Electrical and Electronics Engineers (IEEE), 2011-3)
We present rigorous solutions of electromagnetics problems involving 3-D dielectric photonic crystals (PhCs). Problems are formulated with recently developed surface integral equations and solved iteratively using the multilevel fast multipole algorithm (MLFMA). For efficient solutions, iterations are accelerated via robust Schur-complement preconditioners. We show that complicated PhC structures can be analyzed with unprecedented efficiency and accuracy by an effective solver based on the combined tangenti...
Analysis of hypersonic flow using three dimensional Navier-Stokes equations
Özgün, Muharrem; Eyi, Sinan (2014-01-01)
© 2014 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.The purpose of this study is to develop an accurate and efficient CFD code that can be used in hypersonic flows. The flow analysis is based on the three dimensional Navier-Stokes equations. These equations are solved by using Newton’s method. The analytical method is used to calculate the Jacobian matrix. Flow parameters and convective heat transfer are analyzed on Apollo AS-202 Command Module. Especially, temperature...
Analysis of hypersonic flow using three dimensional navier-stokes equations
Özgün, Muharrem; Eyi, Sinan; Department of Aerospace Engineering (2016)
Metallic materials in aerospace structures are exposed to impact type loads depending on their usage area. High strain rate material characterization of metallic materials is very crucial to properly prepare finite element models to be used in impact loading situations. Johnson-Cook material model is a suitable material model to represent the behaviour of metallic materials at high strain rates. In the present thesis study, parameters of the Johnson-Cook material model for Al 7075-T651 are determined utiliz...
Citation Formats
A. E. Yılmaz, “Analysis of electromagnetic scattering problems with the finite element method,” Middle East Technical University, 2000.