Adaptive micro-perforated plate sound absorber and real-time micropore adjusting method thereof

Abstract

The invention discloses an adaptive micro-perforated plate sound absorber and a real-time micropore adjusting method thereof. The sound absorber comprises a micro-perforated plate, wherein micropores are uniformly distributed on the micro-perforated plate; the micro-perforated plate is a piezoelectric film micro-perforated plate, is made from a piezoelectric film, and is provided with a circuit lead end connected with a piezoelectric film electrode; the circuit lead end is connected with an active control circuit; the active control circuit comprises a piezoelectric film driving circuit, an adaptive controller and a noise detector which are connected with the circuit lead end in turn; and a cavity formed by the piezoelectric film micro-perforated plate and side walls and a rear wall at the periphery of the plate is a piezoelectric film micro-perforated plate resonant sound absorption structure. The size of the micropores on the piezoelectric film micro-perforated plate is adjusted in real time through the piezoelectric effect of the piezoelectric film, so that the aims of optimizing the sound absorption coefficient of the micro-perforated plate resonant sound absorption structure in real time according to the sound wave characteristic of incident noise and greatly expanding the effective sound absorption frequency band of the micro-perforated plate resonant sound absorption structure can be fulfilled.

Description

technical field [0001] The invention relates to a resonant sound-absorbing structure for real-time adjustment of the aperture size of micropores on a piezoelectric film micro-perforated plate by utilizing the piezoelectric effect. Through active control and real-time adjustment of the size of the micropores on the piezoelectric film microperforated plate, a good sound absorption effect can be obtained in a wide frequency range. Background technique [0002] Noise is the third largest pollution source that harms the environment besides air pollution and water pollution. With the development of modern science and technology and the acceleration of social progress, the rapid development of mechanical processing and transportation has brought convenience to society, but at the same time, radiated noise has also brought harm. Research and control of noise is not only an urgent need to protect the environment, but also a problem that must be solved to improve the quality of indus...

AI Technical Summary

Problems solved by technology

[0005] However, the aperture size parameter of the micro-perforated plate with resonant sound-absorbing structure is determined, so the sound-absorbing frequency band and sound-absorbing coefficient of this specific structure can be calculated according to Professor Ma Dayou’s micro-perforated plate theory, for example At present, the micro-pore size of the micro-perforated plate used in large quantities is about 0.8 mm, and its sound absorption frequency band is about 2 to 4 1 / 3 octave bands, which is relatively narrow.

This shows that once the various parameters of the structure are designed, the effective sound absorption center frequency is fixed and the frequency band is narrow

Today, the environment for sound absorption and noise reduction using micro-perforated plate resonant sound-absorbing structures is more complicated, such as large-scale power equipment, roads and other open environments, and the noise signal has the characteristics of wide frequency band and complex spectrum

In this case, a traditional single-layer micro-perforated plate resonant sound-absorbing structure has a fixed effective sound-absorbing center frequency and a narrow frequency band, which determines that it cannot effectively deal with these complex noise environments.

At present, if the effective sound absorption coefficient of the resonant sound-absorbing structure of the micro-perforated plate is to be improved in a wide frequency band, the first is to further reduce the size of the micro-holes on the micro-perforated plate, but the corresponding perforation density will be greatly increased, and the processing The cost will also increase significantly

At the same time, since the aperture size of the micropores is still fixed, although the effective sound absorption bandwidth has been expanded to a certain extent, it is still not enough to cover the entire frequency range of low frequency, intermediate frequency and high frequency, and the sound absorption ability in complex noise environments is still limited.

Another way is to adopt a multi-layer composite micro-perforated plate resonant sound-absorbing structure. The perforation rate and micro-pore size parameters of each layer of micro-perforated plate can be different, so that it can simultaneously absorb low-frequency, medium-frequency and high-frequency noise. , but this solution obviously increases the structural complexity, and the material cost and processing cost will greatly increase

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