Nonlinear magnetic negative stiffness active sound absorption device

Abstract

The invention relates to the technical field of noise control and in particular to a nonlinear magnetic negative stiffness active sound absorption device which comprises a sound absorbing structure, a modulation controller and a noise frequency acquiring component. The sound absorbing structure comprises a base body, a diaphragm and an electromagnet. The base body is hollow and has an open on the top. The diaphragm coats the open of the base body. The diaphragm and the base body together form a sound-absorbing cavity the bottom of which is provided with the electromagnet. The outer surface of the diaphragm is provided with an iron sheet. One end of the modulation controller is electrically connected to the electromagnet and the other end of the modulation controller is used as a signal receiving port to be connected with the signal output port of the noise frequency acquiring component. The sound absorption device can change the negative stiffness of the electromagnet to a film according to the different noise frequencies so as to make the resonance frequency of the film structure coincide with the noise frequency, thereby realizing controllable active sound absorption performance of noise with different frequencies, enlarging the valid sound absorption frequency band of the sound absorption structure, and enhancing the environment adaptability of the sound absorption structure.

Description

technical field [0001] The invention relates to the technical field of noise control, in particular to a nonlinear magnetic negative stiffness active sound absorption device. Background technique [0002] In the field of noise control, membrane material is one of the commonly used sound-absorbing materials. The film combines the closed cavity to form a resonant sound-absorbing structure. Its sound-absorbing characteristics are related to the tension, surface density and depth of the back cavity of the film. It usually has better sound-absorbing performance near the resonance frequency. In practical applications, it is often combined with micro-perforation and other methods. To expand its sound absorption bandwidth. [0003] Micro-perforated sound-absorbing structure occupies an extremely important position in many resonant sound-absorbing structures. Since the groundbreaking work of Academician Ma Dayou in the 1970s, the sound-absorbing structure of micro-perforated panels...

AI Technical Summary

Problems solved by technology

There is also a magnetic negative stiffness sound-absorbing device, which can achieve low-frequency sound absorption with a small back cavity structure, but the resonance frequency is fixed and the environmental adaptability is poor.

In view of this, it is urgent to find another way to solve the problem of poor environmental adaptability of the magnetic negative stiffness film sound-absorbing device

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