Acoustic Properties of Open-Celled Metal Foams with a Stepwise Pore Size Gradient

摘要

The acoustic properties of open-celled metal foams are a function of their open pore size, relative density, and their constituent base material. While such foams offer a robust light-weight alternative to non-structural foams, their acoustic properties typically cannot compete with traditional polymeric foams due to their larger pore size. Here, we explore the possibility of compressing open-celled metal foams as a method for improving their acoustic properties. Aluminum foam samples were compressed in a controlled manner to reduce their effective pore size before being stacked together to simulate foams with discrete, stepwise pore size gradients. The effect of compression and stacking sequence on absorption was then analyzed using two-microphone impedance tube tests. Our results indicate that stepwise gradient foams offer a more effective acoustic material alternative to uniform foams.