An investigation on the optimization of air layers and porous elastic materials for sound in-sulation of composite structure

Based on the Biot theory of sound propagation in multi-layer materials, the method of transfer matrix were used to derive the transmission loss of typical layered-structure consists of elastic solid, fluid and porous material. The influence of air layer and porous material on sound insula-tion performance of multi-layer structure have been discussed by numerical calculation. The sound insulation performance of the composite structure has been optimized in the specific fre-quency band by using genetic algorithm and transfer matrix. The results indicate that the air layer and porous materials can improve the sound insulation performance of the composite structure. The distribution of the air layer and porous materials also has great influence on the sound insulation performance.