A new method for location of the main contribution modes by the decomposed sound pressure

Abstract

The control of loud structure-borne noise inside car cabins is commonly by analyses such as panel acoustic contribution analysis, sensitivity analysis, and optimization analysis, to find suitable and practical structural modifications. However, these analyses are usually repeated dozens of times before accessing effective structural modifications, which requires more computation and time. This paper presents a new way to decompose sound pressure and quickly locate structural and acoustic modes of the main contribution for efficient access of feasible structural modifications. The decomposition process of the sound pressure inside structure-acoustic coupled systems was summarized by analyzing specific mathematical formulas. The details for locating the structural and acoustic modes of the main contribution by the decomposed sound pressure were investigated, taking a typical structure-acoustic coupled system of a rigid box with one flexible wall at bottom as an example. To evaluate the correctness of the main contribution modes, modifications were suggested in the structural modes of the main contribution, based on the mechanics of structure-acoustic coupling. The results indicated that the interior sound pressures of structure-acoustic coupled systems are decomposed into matrices by certain mathematical formulas. The main contribution modes are located by analyzing larger data in the decomposition matrices. The modifications in the structural modes of the main contribution reduce the corresponding sound pressure, which shows the correctness of the main contribution modes found. Furthermore, one way for quick suggestion of effective structural modifications was proposed, which offers a potential option for the reduction of structure-borne noise inside car cabins.