Sound absorption mechanism of sound absorbing materials
According to the sound absorption mechanism, sound absorption materials are divided into:
① Porous materials, which attenuate sound waves through many small open channels from the surface to the interior, they mainly absorb medium and high frequency sound waves, there are various organic or inorganic fiber aggregates, fibers and their products, as well as open-cell foam and expanded perlite products. porous structure.
② Flexible materials that absorb sound by resonance (such as closed-cell foam, which absorbs medium frequencies), film-like materials (such as plastic film or cloth, canvas, linoleum and artificial leather, which absorb low and medium frequencies), plate-like materials (such as plywood, hard fiberboard, Asbestos cement boards, gypsum boards, etc. absorb low frequencies) and perforated boards (made by perforating various sheet materials or metal plates to absorb medium frequencies).
The combination of the above materials can expand the sound absorption range, improve the sound absorption coefficient, stick decorative sound-absorbing panels on the wall or ceiling, install porous materials and perforated panels or film-like materials on the wall, and even use floating clouds to suspend them. Room sound quality and noise control. In addition to absorbing air-borne sound, porous materials can also attenuate vibrations caused by structure-borne sound and air-borne air-borne sound. Filling porous materials into composite structures composed of various plate-like materials can improve sound insulation ability to reduce the weight of the structure,
For materials that absorb incident sound energy, sound-absorbing materials are mainly used to control and adjust indoor reverberation time, eliminate echoes, and improve indoor listening conditions; they are used to reduce noise in noisy places and improve living and working conditions (see sound absorption and noise reduction) ; Also widely used to reduce noise in ventilation and air conditioning ducts.