A hybrid formulation for the vibro-acoustic analysis of structures in the mid-frequency domain

The mid-frequency field is a hybrid domain for which assembled structures exhibit simultaneously low- and high-frequency behaviours, depending on the material and geometrical properties of the different subsystems. Thus, dealing with the mid-frequency field requires simulation methods which are able to account the differences of behaviour of the different subsystems. A hybrid formulation that is able to correctly predict the vibro-acoustic response of a mid-frequency structure is presented in this paper, it is named the FE-SIF This formulation is based on the coupling of two different formulations, the Finite Elements (FEM) for the low frequency behaving sub parts and the Smooth Integral Formulation (SIF) applied to the high frequency subsystems. The FEM-SIF hybrid method enables to correctly predict the deterministic response of the low frequency parts which is not affected by randomness, and the smooth trend of the contributions of the high frequency parts.