3D isogeometric boundary element analysis and structural shape optimization for Helmholtz acoustic scattering problems

2021 ◽  
Vol 384 ◽  
pp. 113950
Author(s):  
Ahmed Mostafa Shaaban ◽  
Cosmin Anitescu ◽  
Elena Atroshchenko ◽  
Timon Rabczuk
Author(s):  
Steven J. Newhouse ◽  
Ian C. Mathews

Abstract The boundary element method is an established numerical tool for the analysis of acoustic pressure fields in an infinite domain. There is currently no well established method of estimating the surface pressure error distribution for an arbitrary three dimensional body. Hierarchical shape functions have been used as a highly effective form of p refinement in many finite and boundary element applications. Their ability to be used as an error estimator in acoustic analysis has never been fully exploited. This paper studies the influence of mesh density and interpolation order on several acoustic scattering problems. A hierarchical error estimator is implemented and its effectiveness verified against the spherical problem. A coarse cylindrical mesh is then refined using the new error estimator until the solution has converged. The effectiveness of this analysis is shown by comparing the error indicators derived during the analysis to the solution generated from a very fine cylindrical mesh.


2013 ◽  
Vol 327 ◽  
pp. 271-275 ◽  
Author(s):  
Zhi Xue Wu

A gradientless method for two-dimensional shape optimization is developed based on the magnitude of local relative-stress difference along the design boundary. The design boundary is modeled by using cubic splines, which are determined by a number of control points. The optimal shape of a design boundary with constant stress is achieved iteratively by moving control points consecutively (correspondingly, changing the shape of the design boundary) by an amount depending on the relative-stress difference between two neighboring boundary points. The key feature of the optimization method is that no arbitrary threshold stress is required. The result quality in terms of accuracy and efficiency are tested and discussed with several finite element analysis examples.


2020 ◽  
Vol 28 (4) ◽  
pp. 223-245
Author(s):  
Gabriel N. Gatica ◽  
Salim Meddahi

AbstractThis paper extends the applicability of the combined use of the virtual element method (VEM) and the boundary element method (BEM), recently introduced to solve the coupling of linear elliptic equations in divergence form with the Laplace equation, to the case of acoustic scattering problems in 2D and 3D. The well-posedness of the continuous and discrete formulations are established, and then Cea-type estimates and consequent rates of convergence are derived.


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