A composite sound-absorbing structure with variable damping mechanical impedance

Abstract

The invention discloses a variable-damping mechanical impedance combined sound absorption structure. The structure comprises a wall face and a sound absorption material, wherein a support is horizontally installed on the wall face, a bracket is welded to the inner side face of the support and stuck to one side of a viscoelastic hose, a variable-damping mechanical impedance plate is stuck to the other side of the viscoelastic hose, and damping liquid is injected in the viscoelastic hose. The structure can control changes of a damping coefficient and guarantee that a high sound absorption coefficient is achieved at a low frequency, and meanwhile a good sound absorption band width is achieved. Due to combination of variable mechanical impedance and the sound absorption material, the whole combined sound absorption structure is wide in sound absorption audio frequency and has good sound absorption property at low, medium and high frequencies. The variable-damping mechanical impedance sound absorption structure is small in thickness, needed space is small, medium and high frequency sound absorption does not need large thickness, the small thickness of the whole structure is important and excellent property of the combined structure, and the limited-space and high-sound-absorption requirement engineering problem is solved.

Description

technical field [0001] The invention relates to the field of noise control, in particular to a variable damping mechanical impedance composite sound-absorbing structure. Background technique [0002] Sound absorption technology is the core technology of noise control engineering. Sound-absorbing materials usually include porous sound-absorbing materials and resonant sound-absorbing materials. Traditional fibrous sound-absorbing materials are porous sound-absorbing materials, and micro-perforated plates are resonant sound-absorbing structures. The above-mentioned sound-absorbing materials and sound-absorbing structures must have good sound-absorbing effects at low frequencies. The thickness of must be large, which will take up a lot of space. The mechanical impedance structure can obtain sound absorption at low frequencies, but the sound absorption frequency band is not wide. The viscoelastic properties of the traditional mechanical impedance structure come from bulk viscoe...

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Problems solved by technology

The traditional mechanical impedance structure generally selects a certain material as its viscoelastic boundary. After the elastic coefficient is determined, the damping coefficient is determined accordingly with the determination of the material. The sound absorption coefficient is not easy to control, and the sound absorption frequency band is narrow.

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