Statistical modes method-SMM for vibroacoustics calculations of coupled systems

摘要

Evaluating the vibroacoustic response of a fluid-structure coupled system is a relevant issue in many branches of engineering. Tasks related to this field are the analysis of the acoustic environment of the passenger compartment of a vehicle (in the automotive sector) and estimation of the vibrations of a satellite during its launch (in the aerospace sector). Vibroacoustic response is usually calculated by using the finite element method (FEM) for lower frequency band. For higher frequency band, the statistical energy analysis (SEA) is the usual choice. In this sense, the lack of a method capable to capture the response of the mid-frequency zone or even the full band is a matter of great interest for researchers from the last decades. A novel analytical model to evaluate the full band vibroacoustic response of a coupled system in a simplified way with average response is presented, the statistical modes method (SMM). The SMM provides the maximum responses on each frequency band and the overall response through the integral over the frequency domain. The eigenvalues are calculated based on modal density equations updated to also work in fundamental frequencies, the eigenvectors are not calculated in order to keep the method simple, and however, the variables which need it as coupling factor and nodal forces are analytically approximated from geometrical information and mode number. The method is validated over analytical, FEM, SEA and experimental results. The satellite Amazonia 1 from Instituto Nacional de Pesquisas Espacias acoustic tests was used for the experimental validation.