Simulation of wave problem in unbounded domains by commercial FEA software
  Revised:June 02, 2005
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DOI:10.7511/jslx20075122
KeyWord:absorbing boundary,modified Higdon's ABCs,equation transformation,high order,FEA code,Msc.Marc
WANG Bing-jian  LIU Tian-yun
Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China
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Abstract:
      In practical calculation,it is often essential to truncate the unbounded medium in order to render the computational domain finite and apply absorbing boundary conditions at the computational boundary.A new method based on Higdon's absorbing boundary(HK ABCs) is introduced,which simplifies the computation procedure of the HK ABCs' partial equation by introducing a number of auxiliary variables.Then appropriately transforming the simplified equations to the form that is feasibly applied to commercial finite element code.In the transformation of the FEA discrete equations,the coherent forces which derived from the ABCs is moved to the right of the equation,equated to the boundary forces.In the resultant application,we can use any order of the ABCs in the FEA computation,meanwhile,keep FEA code running stably.Numerical examples are presented to illustrate the effectiveness of the method.Current limitations and possible extensions are also discussed.