Analysis of Structural and Non-Structural Problems by Coupling of Finite and Infinite Elements

2014 ◽  
Vol 578-579 ◽  
pp. 445-455
Author(s):  
Mustapha Demidem ◽  
Remdane Boutemeur ◽  
Abderrahim Bali ◽  
El-Hadi Benyoussef
Keyword(s):  
Numerical Technique ◽  
Near Field ◽  
Main Idea ◽  
Far Field ◽  
Mining Operations ◽  
Infinite Element ◽  
Infinite Elements ◽  
Structural Problems ◽  
Infinite Element Method ◽  
Element Method

The main idea of this paper is to present a smart numerical technique to solve structural and non-structural problems in which the domain of interest extends to large distance in one or more directions. The concerned typical problems may be the underground excavation (tunneling or mining operations) and some heat transfer problems (energy flow rate for construction panels). The proposed numerical technique is based on the coupling between the finite element method (M.E.F.) and the infinite element method (I.E.M.) in an attractive manner taking into consideration the advantages that both methods offer with respect to the near field and the far field (good accuracy and sensible reduction of equations to be solved). In this work, it should be noticed that the using of this numerical coupling technique, based on the infinite element ascent formulation, has introduced a more realistic and economic way to solve unbounded problems for which modeling and efficiency have been elegantly improved. The types of the iso-parametric finite elements used are respectively the eight-nodes (Q8) and the four-nodes (Q4) for the near field. However, for the far field the iso-parametric infinite elements used are the eight-nodes (Q8I) and the six-nodes (Q6I).

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.

Efficient Structural Acoustic Analysis Using Finite and Infinite Elements and Parallel Processing Architectures

1997 ◽  
Author(s):  
Stewart W. Moore ◽  
Henno Allik
Keyword(s):  
Acoustic Analysis ◽  
Three Dimensional ◽  
Infinite Element ◽  
Analytical Technique ◽  
Infinite Elements ◽  
Infinite Element Method ◽  
Modeling Practices ◽  
Processing Architectures ◽  
Memory Architectures ◽  
Element Theory

Abstract The analysis of three-dimensional shell structures submerged in an infinite fluid and subjected to arbitrary loadings is a computationally demanding problem regardless of the analytical technique used. Over the past several years, we have developed a combined finite/infinite element method of solving this class of problems that is more efficient than other available techniques, and have implemented it in a comprehensive set of computer programs called SARA. This paper presents an overview of our work in parallizing this software. In the first part of the paper, we describe our method for solving the fluid-structure interaction equations including infinite element theory, and modeling practices that have evolved for solving cylindrical geometries. The second part of the paper addresses parallalization of SARA-3D on both shared and distributed memory architectures. The SARA implementation of the method is described along with sample problems, and a comparison to a SARA-3D solution is provided.

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.

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