Study On The Effect Of Alternating Voltage Excitation On The Sound Absorption Characteristics Of PVDF Piezoelectric Micro-perforated Panel And Its Array

Micro-perforated panel absorber(MPPA)has the characteristics of light and thin,green and pollution-free,which is used in windows,ceilings,aircraft and other fields,but in the environment of variable noise frequency,the traditional sound absorption characteristics of MPPA can not be adjusted and can not effectively absorb sound and reduce noise.In the past few decades,piezoelectric materials have been used as sound absorption control layer for sound absorption and noise reduction.Because of its good inverse piezoelectric effect,piezoelectric materials have a considerable development prospect in the field of active noise reduction through external excitation voltage.In this paper,the mechanism of active and passive sound absorption and noise reduction of polyvinylidene fluoride piezoelectric micro-perforated panel(PVDF-MPPA)is studied.The PVDF film is numerically machined into piezoelectric micro-perforated panel,and three kinds of PVDF-MPPA arrays with different structures are designed to realize the sound absorption performance of the integration of active and passive noise reduction.By changing the external excitation signal of each unit of PVDF-MPPA,the sound absorption coefficient near the excitation frequency point in the low frequency band can be effectively improved.To realize multi-frequency sound absorption and noise reduction with adjustable sound absorption characteristics,the specific research contents are as follows:Firstly,this paper theoretically analyzes the sound absorption mechanism of rigid micro-perforated panel,flexible micro-perforated panel,external shunt circuit PVDF-MPPA and the active sound absorption mechanism of piezoelectric materials,which provides a theoretical basis for exploring the sound absorption mechanism of active and passive noise reduction of PVDF-MPPA array.Secondly,the frequency spectrum characteristics of polyvinylidene fluoride(PVDF)piezoelectric film and piezoelectric micro-perforated panel array are tested in the silent chamber,and the fluctuation mechanism of sound absorption coefficient of PVDF-MPPA at the excitation frequency is analyzed experimentally.At the same time,three kinds of PVDF piezoelectric micro-perforated panel array bases and external alternating voltage excitation circuit systems are designed.Finally,the standing wave tube method is used to test the sound absorption characteristics of the PVDF-MPPA array in the 100Hz-1600 Hz range.The experimental results show that the PVDF-MPPA array can effectively improve the sound absorption performance near the excitation frequency point by adjusting the external driving signal.According to different noise environments,the excitation frequency signal similar to the noise frequency is applied to the PVDF-MPPA array,selectively improve the sound absorption characteristics of PVDF-MPPA in the desired frequency band.