Modified analytical model for predicting the nonlinear acoustic characteristics of perforated sound-absorption structures at high sound pressures.

Abstract

This paper presents a modified model for predicting the nonlinear acoustic characteristics of a microperforated plate at high sound pressure levels with increased accuracy of PARK Model. Based on PARK Model, the acoustic impedance of the cavity behind the plate is taken into account in the equivalent circuit to adjust the velocity in the perforations. The modified model was compared with the previous model to verify its accuracy at high sound pressure levels. Furthermore, to establish that the proposed model also has higher accuracy when considering perforated structures with complex cavities, a four-unit coupled structure (FUCS) composed of four coiled-up space channels was constructed. A finite-element model was used to verify the accuracy of our proposed model. This confirmed that our model calculates the sound-absorption coefficient and average particle velocity in the microholes more accurately than several other models at 155 dB. Experimental assessments of the sound-absorption performance of the FUCS within the 300-1900 Hz range confirmed the accuracy of the model. When considering perforated sound-absorption structures at high sound pressure levels, this model is more accurate than PARK's Model and, therefore, has potential application value in relation to the extreme noise fields experienced in aerospace applications.