Analysis and optimization design for sound absorption performance of gradient elastic porous materials

Gradient porosity structure has a great influence on sound absorption performance of porous materials, and it can broaden sound absorption frequency band of porous materials. Here, elastic porous material with gradient porosity was taken as the study object, and based on Biot theory and the transfer matrix method, effects of common gradient structure and gradient difference on its sound absorption coefficient were studied. The multi-island genetic algorithm (MIGA) was used to search the optimal thickness distribution of its gradient structure. The study showed that through reasonably designing porosity and layer thickness, the sound absorption performance of the expected frequency band can be improved; the gradient structure of porosity from high to low and then from low to high can obviously improve the broad frequency band sound absorption coefficient; the study results have important guiding significance for designing elastic porous materials and their application in acoustic package. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.