多孔吸音材料的研制（Development of porous sound-absorbing material）.doc

多孔吸音材料的研制（Development of porous sound-absorbing material） The principle of sound absorption The vibration sound source to the object, it is caused by vibration in the air and the adjacent formation acoustic wave, and in the air medium to spread around. When the incoming sound component material surface, part of the sound energy is reflected through a part of materials, as well as a component material in vibration or sound due to the propagation of friction with the surrounding medium, the sound energy into heat energy, sound energy loss, often said that the sound is absorbed by the material. The sound absorption performance of the sound absorption coefficient of the material is expressed by the sound absorption coefficient. For the E /E0 absorption loss coefficient, and penetration coefficient is E / E0 and penetration. The surface characteristics of the sound absorption properties of materials and materials in their structure, thickness and material of the outside, and also the direction and frequency of the incident sound Sound-absorbing material 1 on from the surface to the sound-absorbing material in Open channel to the acoustic wave attenuation of the porous materials department of many small, to absorb the high frequency sound waves, with fibrous tissue accumulation of various organic or inorganic fiber and its products as well as the porous structure of open cell foam and expanded perlite products. The effect of the resonance absorption by flexible materials (such as closed cell foam, absorption, intermediate) membrane material (such as plastic or cloth, canvas, leather and artificial leather, absorption of low frequency), the plate material (such as plywood, hardboard, asbestos cement board and gypsum board, absorbing low frequency) and perforation board (all kinds of plate material or a metal plate perforated and prepared, absorption frequency). The above composite materials used, can expand the range of sound absorption, improve sound absorption coefficien