| 摘要 |
#CMT# #/CMT# The acoustic material has an acoustic resistance ranging between a product of .2, P and c and a product of 1.5, P and c and an acoustic reactance ranging between a product of .2, P, c and a product of 1, P and c on a range of frequencies between 500 and 5000 hertz, where the P represents a density of outer fluid medium and C represents a speed of sound in the medium. The material is formed from a fibrous fabric material layer (11) and a glass fabric layer (13), where the layers are impregnated with a material such as phenolic thermoplastic resin and epoxy resin. #CMT# : #/CMT# An independent claim is also included for a method for fabricating a porous acoustic material. #CMT#USE : #/CMT# Porous acoustic material for forming a porous acoustic wall of a Helmholtz resonator type acoustic processing element or acoustic processing device (claimed) that is utilized in a ventilating head, bell mouth and casing, of a ventilator in a ventilation air supply circuit of aircraft for processing noise emitted by a machine e.g. turbo jet engine, of the aircraft in airport. #CMT#ADVANTAGE : #/CMT# The porous acoustic material permits to reduce noise emitted in front of a conduit communicating with a cabin of aircraft, thus improving comfortness of passengers and constructors of transport unit. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a sectional view of an acoustic porous material for being used as acoustic skin. 10 : Layer assembly 11, 15 : Fibrous textile material layers 13, 17 : Glass fabric layers. |
