Sound absorption design and characteristics of variable-section perforated double-porosity multiscale aerogel

Abstract

A constant-section perforated double-porosity multiscale porous material (CDMPM) introduces periodically distributed straight mesoperforations in an appropriately selected traditional single-porosity substrate. In this work, the effects of mesopore radius ([Formula: see text]) and mesopore height ([Formula: see text]) on the sound absorption performance are numerically investigated using graphene-polyvinyl alcohol aerogel (GPA-1) as a microporous substrate. The findings indicate that adjusting mesopore parameters enables to tune the frequency band and thereby enhancing sound absorption performance. However, CDMPM exhibits insufficient performance in broadband and low-frequency application scenarios. To address this issue, a variable-section perforated double-porosity multiscale porous material (VDMPM) with stepped mesopore profile is proposed via the combination of CDMPMs with different perforation parameters. The influence of multiscale design parameters on the sound absorption characteristics of VDMPM is studied, and the key parameters are adjusted based on CDMPM. The optimized design demonstrates global acoustic characteristics, with absorption peaks at low frequencies and efficient broadband absorption in the mid-to-high frequency range. The stepped mesopore profile of VDMPM induces a sophisticated pressure diffusion effect and expands the energy dissipation region. Finally, the applicability of the proposed perforation strategy is examined using rockwool and melamine foam as alternative microporous substrates. The findings of this research provide practical principles to guide the multiscale structural design of double-porosity materials and to ensure effective enhancement of sound absorption performance of traditional porous materials.