Optimization of Sound Absorption Properties and Acoustic Impedance of Multilayer Rubber

Firstly, a model for calculating the sound absorption property of multilayer rubber is established by transfer matrix, and experimental samples are prepared to verify the accuracy of the model. Secondly, the effects of dynamic mechanical properties and thickness distribution of multilayer rubber on sound absorption properties were studied based on the dynamic mechanical properties of Styrene Butadiene Rubber (SBR). Lastly, the material and structural parameters were optimized by a genetic algorithm. The results show that for multilayer composite structure rubber, the impedance gradient structure with decreasing acoustic impedance is better than the traditional structure with increasing acoustic impedance. In addition, a “sandwich modulus structure” with high storage modulus in the middle layer and low on both sides was also found. Through the impedance mismatch design between the layers, the energy loss of the acoustic wave in the material was greatly improved, and the sound absorption properties was better than the impedance gradient structure. The average sound absorption coefficient of the “sandwich modulus” structure is 39.6% higher than that of the uniform structure rubber.