The influence of closed pore ratio on sound absorption of plant-based polyurethane foam using control unit model

[Display omitted] In order to improve the environmental-friendly performance and sound absorption performance of petroleum polyurethane (PU) foam, a variety of polyols are used to prepare plant-based PU foams with different closed pore ratios. In this research, the microstructure of PU foam was replicated and a periodic unit cell (PUC) model with ideal conditions was created. The model was created as tetrakaidecahedrons with pores of different sizes in the different cytoderms. The non-acoustic parameters of the Johnson-Champoux-Allard (JCA) acoustic model can be obtained by finite element analysis of the PUC model under specific conditions. The theoretical sound absorption coefficient of different foams was obtained through the JCA acoustic model. The experimental results show that the increase of the closed pore ratio can improve the sound insulation performance of PU foam. Both the experimental results and the simulation results show that the increase in closed pore ratio can improve the sound absorption effect of PU foam on low-frequency noise. The simulation results further show that the sound absorption coefficient of PU foam first increases and then decreases with the increase in closed pore ratio. And the change of the closed pore ratio has a greater influence on the air-flow resistivity and tortuosity.