Sound absorption performance of various nickel foam-base multi-layer structures in range of low frequency
(College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China)
Abstract: Commercial 3D reticular nickel foam and its composite structure were investigated on the sound absorption at 200-2000 Hz. The absorption performance of foam plates 1-5 layers (1-layer thickness: 2.3 mm; porosity: 89%; average pore-diameter: 0.57 mm) was found to be poor, and could be improved by adding backed cavum or front perforated thin sheet. The absorption coefficient could reach about 0.4 at 1000-1600 Hz for the composite structure of 5-layer foam with a backed 5 mm-thick cavum, and even 0.68 at about 1000 Hz for that of 2-layer foam with the same cavum and a perforated plate closely in front of the foam.
Key words: reticular metal foam; reticular nickel foam; composite structure for sound absorption; low frequency sound absorption