Study On Control Of Low-frequency Noise In Vehicles Based On Piezoelectric Effect

With the development of advanced technologies,it’s improved that eliminate the level of vehicle interior high-frequency noise and vibration.However,it’s stubborn problem that the ways of low-frequency noise result from various sound sources in the vehicle.With the development of all kinds of smart materials,it’s a new choice to control of vehicle interior noise and vibration.In this thesis,the piezoelectric shunt damping system is proposed to control of vehicle interior noise and vibration below 200 Hz.It is verified through theoretical and experimental analysis.Firstly,it is to depend on mechanics of piezoelectricity that study on different boundary condition have different the linear piezoelectric constitutive equation,a mathematical model of piezoelectric shunt damping system is established.Through the characteristics of the shunting circuit to make sure the type is an R-L circuit in this thesis.Through frequency response analysis to gain the formula of the parameter of the R-L circuit.It is researched on equivalent inductance circuit that apply to part of theoretical and experimental analysis in low-frequency noise.Secondly,the Finite Element Coupling Model of the cavity-piezoelectric plate are established and studied on the vibration of the plate and the change of sound field in the cavity.Through calculating and analyzing,it’s effective way piezoelectric shunt damping system diminish the vibration of the plate and the Sound Pressure Level in the cavity.Through the modal stress of cavity-plate analyses to make sure the number and position of the piezoelectric vibrator.It’s calculated the first modal frequency under the short and open of the piezoelectric vibrator,as on basis of the above conclusion make sure the value of the shunting circuit.Simulation for the response of the vibration of the plate and the Sound Pressure Level in the cavity under with and without piezoelectric shunt damping system and the results show that with piezoelectric shunt damping system is better than without.The results have reference values for the control of high-efficiency low-frequency noise in the vehicle.Finally,according to the Finite Element Coupling Model of the cavity-piezoelectric plate,the experiment is carried out and analyzed.According to the process of the experiment analysis,test for the response of the vibration of the plate and the Sound Pressure Level in the cavity,the experimental results agree reasonably well with the FEM results,which verify the feasibility of piezoelectric shunt damping system applying to control of vehicle interior low-frequency noise.This thesis aims at studying on control of low-frequency noise in vehicles.The obtained conclusion may be provided as a theoretical guidance for control of low-frequency noise,which is practical significant and instructive to the field of aviation and aerospace.