Acoustic scattering by multicracks using a boundary finite element method

Advances in Boundary Element Techniques V (V.M.A. Leitão, M.H. Aliabadi: editors), EC Ltd, Eastleigh, UK (2004), pp. 161-168
https://web.tecnico.ulisboa.pt/~ist12831/proc/2004-Alves-Beteq04.pdf

The numerical simulation of crack scattering is an exterior problem where the use of boundary element methods is recommended. However when considering Neumann boundary conditions in the crack, difficulties connected to the hypersingularity in double layer potential kernel arise. The use of a boundary variational formulation on the boundary allows to overcome this difficulties. This was introduced in Nedelec [14] for the Laplace equation, and developed by Hamdi [9] for the case of acoustic scattering. The case of flat cracks has been addressed by Ha Duong [8]. In the case of a single flat cracks this method has been has been applied [1] with robust results also in the elastic crack scattering framework. In [3] the method was extended to non-planar cracks and here we present the multicrack case, showing simulations for the convergence of the method and we discuss some results concerning crack identification.