A Generalized Collocation Approach for Acoustic Analysis of Mixed Regular and Thin Bodies

In several applications of boundary element methods to acoustic and vibroacoustic analysis there is the need to model thin shells. Typically the classical Helmholtz integral equation is considered to breakdown for thin geometries and alternative approaches are used. In this paper it is however showed that the breakdown is not related to the Helmholtz integral equation itself, but instead is due to the discretization technique. An extension of the classical collocation approach that permits to bypass the thin shape breakdown is then proposed. The new discretization technique is referred as generalized collocation since the collocation point is no more placed on the integration surface but in the computational domain. Several numerical example are presented in order to show the accuracy and robustness of the proposed method.