Finite Element Method Simulations of the Near-Field Enhancement at the Vicinity of Fractal Rough Metallic Surfaces

2004 ◽  
Vol 108 (9) ◽  
pp. 2939-2947 ◽  
Author(s):  
Miodrag Micic ◽  
Nicholas Klymyshyn ◽  
H. Peter Lu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Near Field ◽  
Field Enhancement ◽  
Metallic Surfaces ◽  
Element Method

An Extrapolation Method to Compute Far-Field Pressures From Near-Field Pressures Obtained by Finite Element Method

1995 ◽  
Author(s):  
Jamal Assaad ◽  
Christian Bruneel ◽  
Jean-Michel Rouvaen ◽  
Régis Bossut
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Near Field ◽  
Radiation Condition ◽  
Directivity Pattern ◽  
Extrapolation Method ◽  
External Boundary ◽  
Finite Width ◽  
Far Field ◽  
Element Method

Abstract The finite element method is widely used for the modeling of piezoelectric transducers. With respect to the radiation loading, the fluid is meshed and terminated by an external nonreflecting surface. This reflecting surface can be made up with dipolar damping elements that absorb approximately the outgoing acoustic wave. In fact, with dipolar dampers the fluid mesh can be quite limited. This method can provides a direct computation of the near-field pressure inside the selected external boundary. This paper describes an original extrapolation method to compute far-field pressures from near-field pressures in the two-dimensional (2-D) case. In fact, using the 2-D Helmholtz equation and its solution obeying the Sommerfeld radiation condition, the far-field directivity pattern can be expressed in terms of the near-field directivity pattern. These developments are valid for any radiation problem in 2D. One test example is described which consists of a finite width planar source mounted in a rigid or a soft baffle. Experimental results concerning the far-field directivity pattern of lithium niobate bars (Y-cut) are also presented.

Determination of Far-Field Pattern of Rigid Scatterers Using Independent Finite Element Method and Eigenfunction Expansion, Part 1: Axisymmetric Scattering

1996 ◽  
Vol 118 (4) ◽  
pp. 575-582 ◽  
Author(s):  
C. P. Vendhan ◽  
C. Prabavathi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Eigenfunction Expansion ◽  
Near Field ◽  
Prolate Spheroid ◽  
Field Pattern ◽  
Far Field ◽  
Outer Domain ◽  
Far Field Pattern ◽  
Element Method

The near-field steady state scattered potential around a rigid scatterer subjected to plane incident wave is computed using the finite element method with radiation boundary dampers on a finite truncation boundary. Then the solution in the outer domain is sought in the form of an eigenfunction expansion and the expansion coefficients are obtained using the finite element solution on the truncation boundary as Dirichlet boundary condition. The scattered far-field pattern is derived from this solution for prolate spheroid and hemispherically capped cylinder problems.

Modeling recent experiments of apertureless near-field optical microscopy using 2D finite element method

2003 ◽  
Vol 221 (1-3) ◽  
pp. 13-22 ◽  
Author(s):  
R. Fikri ◽  
D. Barchiesi ◽  
F. H’Dhili ◽  
R. Bachelot ◽  
A. Vial ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optical Microscopy ◽  
Near Field ◽  
Element Method

Simulation of Interfacial Corner Cracks in Bimaterial Systems

2012 ◽  
Author(s):  
Badrinath Veluri ◽  
Henrik Myhre Jensen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Front ◽  
Near Field ◽  
Three Dimensional ◽  
Strain Energy Release ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Corner Cracks ◽  
Element Method

A phenomenological model focused on modeling the shape of such interface cracks and calculating the critical stress for steady-state propagation has been developed. The crack propagation is investigated by estimating the fracture mechanics parameters that include the strain energy release rate, crack front profiles and the three-dimensional mode-mixity along the crack front. A numerical approach is then applied for coupling the far field solutions utilizing the capability of the Finite Element Method to the near field (crack tip) solutions based on the J-integral. The developed two-dimensional numerical approach for the calculation of fracture mechanical properties has been validated with three-dimensional models for varying crack front shapes. In this study, a custom quantitative approach was formulated based on the finite element method with iterative adjustment of the crack front to estimate the critical delamination stress as a function of the fracture criterion and corner angles. The implication of the results on the delamination is discussed in terms of crack front profiles and the critical stresses, which can then be used as the framework for modeling reliability of advanced interconnects system.

Wave Diffraction of Steep Stokes Waves by Bottom-Mounted Vertical Cylinders

2003 ◽  
Author(s):  
J. W. Kim ◽  
J. H. Kyoung ◽  
R. C. Ertekin ◽  
K. J. Bai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Near Field ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Two Dimensional ◽  
Highly Nonlinear ◽  
Stokes Waves ◽  
Vertical Cylinders ◽  
Element Method

The diffraction of highly nonlinear Stokes waves by vertical cylinders of circular cross section is numerically simulated in the time domain. A finite-element method, based on Hamilton’s principle, is used to discretize the fluid domain. The Stokes waves, input at the numerical wave maker, are obtained numerically from the two-dimensional steady solution of the finite-element method. A new matching scheme is developed to match the two-dimensional wave at the far field and the three-dimensional diffracted wave in the near field. The method developed here can easily be extended to the diffraction of irregular, nonlinear waves. Numerical examples are presented for the diffraction of Stokes waves with various steepnesses by a circular cylinder. The wave elevation and run-up on the cylinder are calculated and compared with the available theoretical results.

Time domain finite element method for metamaterial-based low frequency near field systems

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhi Gong ◽  
Shiyou Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Frequency Domain ◽  
Time Domain ◽  
Near Field ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Content Type ◽  
The Time Domain ◽  
Element Method

Purpose The purpose of this work is to develop a computational paradigm for performance analysis of low-frequency electromagnetic devices containing both magnetic metamaterials (MTMs) and natural media. Design/methodology/approach A time domain finite element method (TDFEM) is proposed. The electromagnetic properties of the MTMs are modeled by a nonstandard Lorentz model. The time domain governing equation is derived by converting the one from the frequency domain into the time domain based on the Laplace transform and convolution. The backward difference is used for the temporal discretization. An auxiliary variable is introduced to derive the recursive formula. Findings The numerical results show good agreements between the time domain solutions and the frequency domain solutions. The error convergence trajectory of the proposed TDFEM conforms to the first-order accuracy. Originality/value To the best knowledge of the authors, the presented work is the first one focusing on TDFEMs for low-frequency near fields computations of MTMs. Consequently, the proposed TDFEM greatly benefits the future explorations and performance evaluations of MTM-based near field devices and systems in low-frequency electrical and electronic engineering.

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