A stochastic BEM formulation for vibro-acoustic analysis of structures in the mid-to-high frequency range

Predicting the acoustic behaviour of a complex structure in the mid-frequency range is a challenging task due to the complexity of the structure and the involved physical phenomena. Since, in the high- and even mid-frequency range, the variability of the product may have a significant effect on its NVH behaviour, it is important to include this sensitiveness in numerical models. In other respects a detailed description of the structures is necessary for structure borne contributions. The approach proposed in this paper provides a robust method for the vibroacoustic analysis of 3D acoustic domains coupled with structural components in the mid-frequency range. The method is based on a probabilistic approach which introduces uncertainties in the Boundary Element formulation: random geometrical parameters are introduced into the integral representations in order to model the increasing sensitivity of the harmonic vibrational responses to any parameter perturbation when the frequency increases. The stochastic formulation is solved in terms of the expectations of the square boundary kinematic unknowns and is valid in the entire frequency domain. The effectiveness of the formulation is demonstrated in this paper with a numerical application to a 3D model of an acoustic cavity coupled with a vibrating structure and with an internal source.