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Full-Text Articles in Electromagnetics and Photonics
Three-Dimensional Fem-Bem Computation Of Electromagnetic Responses Of Flaws, Jian-She Wang, Nathan Ida
Three-Dimensional Fem-Bem Computation Of Electromagnetic Responses Of Flaws, Jian-She Wang, Nathan Ida
Nathan Ida
Electromagnetic (EM) nondestructive testing of a lossy dielectric material involves exciting the material with an external EM source, measuring responses on a measuring surface, and inferring the location, shapes and properties of possible flaws. But the interaction of electromagnetic fields with the material is a highly complex process. Three-dimensional computation is therefore required to accurately predict the overall interaction of EM fields with the material and flaws. The problem is unbounded, and strong inhomogeneity exists inside the material, due to the presence of flaws. The coupling of the finite element method (FEM) and the boundary element method (BEM) provides an …
A Transient, Axisymmetric Formulation For Modeling Of Composite Materials, Min Eig Lee, Nathan Ida
A Transient, Axisymmetric Formulation For Modeling Of Composite Materials, Min Eig Lee, Nathan Ida
Nathan Ida
The electrically small loop is of great practical importance in finding direction and probing magnetic fields. In [1], it was proposed for communication from above ground to observation points within coal mines. In this paper, the interactions of electromagnetic field, produced by a current-excited small loop, with lossy and lossless materials are investigated. The use of a small loop for the NDE of composite materials is also presented. To achieve these goals, solutions of interface problems become necessary. Since the exciting current is not restricted to be time-harmonic, we will solve the problems in the time domain. Also, to obtain …
Performance Of Large Scale Finite Element Eddy Current And Ultrasonic Models On A Vector Computer, Nathan Ida, Reinhold Ludwig
Performance Of Large Scale Finite Element Eddy Current And Ultrasonic Models On A Vector Computer, Nathan Ida, Reinhold Ludwig
Nathan Ida
Following the early success of finite element modeling of magnetostatic and eddy current nondestructive testing phenomena, considerable effort has taken place in order to extend these models to full three dimensional geometries [1,2]. More recently, the formulation of the elastic wave equations has been implemented and applied to the solution of ultrasonic testing situations [3,4].
A 3-D Fem-Bem Model For Electromagnetic Wave Interactions With Material, Jian-She Wang, Nathan Ida
A 3-D Fem-Bem Model For Electromagnetic Wave Interactions With Material, Jian-She Wang, Nathan Ida
Nathan Ida
This paper continues the authors effort in numerical modeling of electromagnetic forward scattering for high frequency nondestructive testing (NDT) applications. Started in [1], a two-dimensional problem in the time domain was solved by finite difference method in conjunction with a local absorbing boundary condition located some distance away from the scatterer. In the present work, more complicated, three-dimensional models in the frequency domain are considered. A typical electromagnetic NDT situation involves interaction of a given incident wave field with a material sample. Numerical modeling of such an NDT situation usually involves a large solution domain or inverting a very large …
Three Dimensional Finite Element Modeling, Nathan Ida
Three Dimensional Finite Element Modeling, Nathan Ida
Nathan Ida
Numerical modeling of electromagnetic nondestructive testing problems has become in the last few years common enough to be considered an integral part of the engineering design practice. In particular, eddy current modeling activity has been on the increase because of the benefits afforded by such models and their relative simplicity and availability. This is certainly true for two dimensional and axisymmetric modeling where both general [1] and NDT models [2] exist. In many such cases, little more than a small computer and a reasonably trained person are needed.
Numerical Modeling Of Transient Wave Propagation For High Frequency Ndt, Jian-She Wang, Nathan Ida, S. I. Hanharan
Numerical Modeling Of Transient Wave Propagation For High Frequency Ndt, Jian-She Wang, Nathan Ida, S. I. Hanharan
Nathan Ida
Electromagnetic nondestructive testing (NDT) methods use frequencies ranging from low (dc) to high (microwave) frequencies [1]. Applications of numerical methods to model two- and three-dimensional low-frequency (dc or eddy current) nondestructive testing phenomena, where displacement currents can be omitted, were extensively examined, [2,3]. These are all interior boundary value problems. Finite element study of ultrasonic wave propagation and scattering in metals, which is again an interior boundary value problem, was recently reported in [4]. However, modeling of wave propagation for high-frequency NDT problems have not yet been attempted. Recently, finite difference methods in time domain have been successfully applied to …