Research On Active Control Of Sound Absorption Based On PVDP-MPP

As a resonant sound absorption structure,micro-perforated plane absorber(MPPA)is widely used in various noise control fields due to its simple structure,good sound absorption performance and environmental friendliness.In practical applications,once the processing of traditional MPPA is completed,the parameters of aperture,hole spacing and plane thickness are also fixed,and cavity depth is the only parameter to adjust the sound absorption properties.However,due to the long wavelength of the low-frequency wave and the complex spectrum of the environmental noise,it is difficult for the fixed perforated plane absorber to meet the more complex requirements of noise reduction.Therefore,it is a hotpot to improve the sound absorption performance of MPPA on the premise of limited space,affordable cost,and facile structure.To overcome the bottlenecks of traditional rigid MPPA including narrow absorption bandwidth,weakness of response to the low frequency noise,unable to adapt to multiple frequency complex noise source polyvinylidene fluoride(PVDF)membrane was used to be processed into micro-perforation plane(PVDF-MPP).This structure has exhibited robust piezoelectricity,flexibility,and PVDF piezoelectric film was connected with the external drive circuit.It is effective to improve the sound absorption properties of PVDFMPPA by adjusting the excitation electrical signal.Under the action of applied electric field,PVDF-MPP can generate mechanical vibration,and the sound absorption performance of the MPPA can be dynamically regulated by adjusting the input parameters of frequency and amplitude of the electrical signal.This paper has firstly analyzed the theory of MPPA,the theory of flexible plane and the theory of piezoelectric active control.On this basis,according to the piezoelectric active control theory,followed by the establishment of high voltage driving circuit and sound absorption coefficient measurement device.Impedance tube was used to measure the sound absorption coefficients of single layer PVDF-MPPA,double layer PVDFMPPA and parallel PVDF-MPPA under different excitation conditions.The general law concerning the sound absorption properties of PVDF-MPPA inspired by the active sound absorption mechanism was also investigated.In summary,the main reasons for the adjustment of sound absorption performance of PVDF-MPPA under the applied electric field were briefly analyzed and summarized.