On the analysis of coupling strength of a stiffened plate-cavity coupling system using a deterministic-statistical energy analysis method

Abstract

This paper combines the Impedance Mobility Compact Mothed (IMCM) with Statistical Energy Analysis (SEA) method to develop analytical structural-acoustic approach for analysis of a plate-cavity coupling system. The coupled system is composed of an acoustic cavity covered with a rectangular flexible plate that is stiffened by a beam integrated to the inner surface of the plate to modify the coupling strength between the plate and the air inside the cavity. This paper discloses the relationship between the coupling strength and coupling quotient. The results of the study indicate that the coupling strength between the plate and acoustic cavity can be determined by the natural frequency proximity and the matching degree of the mode shapes of the plate and acoustic cavity. Addition of stiffener onto the plate, increase of the plate thickness or decrease of the cavity volume will reduce the coupling strength. The newly proposed coupling coefficient can better quantify the coupling characteristics of the plate and cavity system in the low-middle frequency ranges. The results assessed by the proposed coupling coefficient have been verified by those assessed by the previously defined coupling coefficient and the coupling quotient in the SEA model in the high frequency range.