Study On Low Frequency Sound Absorption Characteristics Of Micro-perforated Panel With Multi-reaonance

The micro-perforated plate has received more attention and development in the field of noise control due to its own beautiful appearance,cleanness and good sound absorption characteristics.However,the conventional micro-perforated plate has a high sound absorption coefficient only at the resonance frequency,and the effective sound absorption band is narrow.If the sound absorption band is widened,it is necessary to increase the back cavity depth of the micro-perforated plate,which greatly limits the application of micro-perforation.Thinner microperforated sheets are required in some lightweight applications.Sound waves can cause vibration of the microperforated plate,which can significantly affect the sound absorption characteristics of the microperforated plate.This topic mainly focuses on the theoretical analysis and experimental research on the above two problems.In this paper,the three-dimensional simulation model of micro-perforated plate was established by COMSOL simulation software.The influences of four structural parameters of aperture,perforation rate,back cavity depth and plate thickness on the sound absorption characteristics of microperforated plates were analyzed.The combined micro-perforated plates in series and parallel are designed.The sound absorption characteristics of different combinations of micro-perforated plates are simulated and analyzed.The results show that the combined structure can effectively widen the sound absorption band of the micro-perforated plate and enhance the sound absorption characteristics.The theoretical calculation results were tested and verified by the transfer function method through the impedance tube.The experimental results and the simulation results were in good agreement.Unreasonable structural parameters can seriously affect the sound absorption effect of micro-perforated plates.The simulated annealing algorithm is used to optimize the structural parameters of single-layer and combined micro-perforated plates.The optimized micro-perforated plate sound absorption effect has been improved significantly.The multi-resonance micro-perforated plate was optimized and the sound absorption coefficient was measured in the reverberation chamber.Compared with the traditional sound-absorbing material,the multi-resonance micro-perforated plate was found to have superior sound absorption characteristics.When the microperforated plate is thin,the vibration of the plate significantly affects its sound absorption characteristics.In this paper,the effect of piezoelectric ceramic coupling on the sound absorbing plate is studied by piezoelectric shunting technology.The influence of the components in the external shunt circuit on the sound absorption characteristics of the piezoelectric ceramics is analyzed through experiments.Through the experimental results,it can be obtained that by using the piezoelectric shunt damping technology,the sound absorption characteristics between the two sound absorption peaks of the microperforated plate can be improved,and the sound absorption effect of the sound absorption body can be improved.