Sound absorbing material with porous structure - is anisotropic with different moduli of elasticity in different directions

摘要

The sound absorbing material has a polyognal cross-section (2) incorporating a porous structure. The material is also anisotropic in that it has a modulus of elasticity E in one direction which is less than the modulus of elasticity in at least one other direction. The material has a soundwave impedance characteristic in one direction which is of the same order of magnitude as the sound wave impedance characteristic of air. The material is made from soft foamed plastic and has a honeycomb cross-section. USE/ADVANTAGE - Sound absorbing material which is cheap to produce.