is no higher than 0.7, and the sound absorption rate in the low-frequency region below 4000Hz is lower than 0.2, so the overall sound absorption coefficient is not high.The sound absorption of closed-cell aluminum foam mainly depends on three ways: one is the sound absorption of helmholtz resonator;Second, crack and micro - hole sound absorption;Third, diffuse absorption.When the closed-cell aluminum foam is cut through the surface, some half-holes will be formed, namely the helmholtz resonator. When the sound waves reach the surface, they will partially enter the hole of the material, causing resonance and sound absorption.There are cracks and micro-pore structures in the material. When air passes through, the viscous resistance of air is generated in the cracks and micro-pores, and the kinetic energy of vibrating air is constantly converted into heat energy and dissipated.
The aluminum foam acoustic panels is used to make road and railway sound insulation screen, metro tunnel noise reduction lining, metro station noise reduction lining, tunnel vent noise reduction lining, railway tunnel noise reduction lining, natnatarium noise reduction lining, conference hall noise reduction lining and so on.
