Structure-acoustic simulation using the modal expansion method and the optimum sensor placement

Abstract

This paper is concerned with the application of the modal expansion method (MEM) to the vibro-acoustic simulation of flexible vibrating structures. The structural vibration field due to the external excitation is expanded by a FEM-based modal expansion method, and the corresponding normal velocity is transferred into the acoustic FE mesh that is generated for the acoustic analysis. In this kind of acoustic simulation, the numerical results are definitely influenced by the accuracy of the expanded vibration field using the modal expansion method, which is in turn influenced by the sensor placement for extracting and determining the reduced numerical mode shapes and the modal participation factors that are essential for the modal expansion method. In this context, the investigation of its effect on the numerical accuracy of the acoustic analysis is of importance. We in this paper compare the acoustic analysis results, such as the sound patterns, power, and pressures, between the regular and optimum sensor placements with MSC/Nastran results for three different boundary conditions.