Phase determination of reverberant structural-acoustic systems using pole and zero distribution

Abstract

This study investigates the phase behavior of a simple coupled structural acoustic system with high modal overlap. It proposes that phase is simply accumulated across the components making up the structure. Classical dynamic solutions breakdown with high modal overlap and complex geometries, and standard Statistical Energy Analysis (SEA) solutions work well for high modal overlap but give no phase information. Many applications such as active control predictions and time-domain signal analysis require phase information. Results of the investigation show that the amount of damping in the system is very important in the estimation of reverberant phase. The amount of energy lost due to coupling with adjacent subsystems was also demonstrated to be important for both acoustic and structural subsystems. The reverberant phase of an acoustic subsystem was found to be affected more by the inclusion of coupling loss to an adjacent structure than the reverberant phase of a structure attached to an acoustic subsystem. The phase of the overall system is calculated by simply accumulating the phase of each of the subsystems.