Sub-regions without subdomain partition with boundary elements

This paper presents a simple and effective numerical procedure to model domains with sectorial heterogeneous properties using the boundary element method. The physical problem is divided into a complete homogenous domain and other non homogeneous sectors. Matrices similar to the standard H boundary element matrix are constructed for each sector, which are related to the energy stored in them. The assembly of the coefficients related to the sectorial matrices in the final boundary element system is done through the direct introduction of unknown variables at internal auxiliary points. Comparatively to the sub-regions technique, the proposed procedure is advantageous, since the effect of interface approximations is attenuated and computer implementation of its corresponding numerical model is simpler.