The purpose of this paper is to obtain the hydro-acoustic modulus of high-strength polyvinyl chloride (PVC) foam through an inversion algorithm based on the measured underwater acoustic insertion loss values of the composite samples, then improve the calculation accuracy of the insertion loss of the composites.

First, the static elastic modulus of high-strength PVC foam is obtained through mechanical tests such as compression and tension, and then the insertion loss of the sandwich composite is calculated using the transfer-matrix method. The reason for the large difference in the calculated values and the measured values obtained by the acoustic pulse-based tube method is that the input value of the elastic modulus of the core material is low. Based on the measured insertion loss values, the underwater acoustic modulus values of five PVC foam samples are then calculated via genetic algorithm inversion.

The quantitative calculation results indicate that the hydro-acoustic modulus value of high-strength PVC foam is higher than the measured static elastic modulus values. The average ratio of hydro-acoustic modulus to compressive modulus is 1.24, and that to tensile modulus is 1.36.

When calculating the hydro-acoustic performance of sandwich composites containing high-strength PVC foam, the error can be reduced by positively correcting the input value of the material's elastic modulus on the basis of the measured value of the static modulus.