Research On Piezoelectric Thin Film Vibration Sensor

Seismic exploration is an important method to find resources,vibration sensor is the core component of seismic exploration equipment,its performance determines the quality of seismic data,electromagnetic vibration sensor is widely used at present,it has high low frequency response,large weight and other problems.PVDF(polyvinylidene fluoride)is a kind of high molecular piezoelectric polymer,which has light weight and good piezoelectric and electromechanical coupling properties.The research of PVDF piezoelectric sensor with low frequency response and high sensitivity has certain practical significance.Therefore,a double-layer PVDF film vibration sensor with cantilever beam structure is designed based on the physical characteristic equation of piezoelectric materials by analyzing the basic principle of vibration sensor used in exploration.It mainly includes the following work: 1.Analyze the mechanical properties of the double film sensitive element,establish the electromechanical integration mathematical model of the double film vibration sensor,complete the derivation of the sensor transfer function,and then design a variety of sensitive element size and signal conditioning circuit according to the requirements.2,using the finite element method for the design of piezoelectric thin film vibration sensor mechanical part has carried on the modal response and harmonic response analysis,through the circuit simulation software to design the signal readout circuit to carry on the simulation analysis,the different feedback capacitance scanning simulation analysis and the feedback resistance parameters,the simulation results show that consistent with the theoretical design.3.The designed piezoelectric thin film vibration sensor was made,including mechanical part and circuit part,and its shaking table test,experimental data show that the test results are consistent with the theoretical design.Finally,a piezoelectric film sensor is presented.The test results show that its sensitivity is about 2.98V/g,and its natural frequency is about 5.5Hz,which meets the basic design requirements.This topic provides some ideas and references for the design of low-frequency piezoelectric thin-film vibration sensor through mathematical modeling-simulation verification-physical production-experimental test.