Design And Properties Simulation On High Temperature Shear Mode Piezoelectric Accelerometer

At present,piezoelectric acceleration sensors account for about 80%of all kinds of vibration sensors.With the development of modern science and technology,many industrial and scientific research departments,such as atomic energy,energy,aerospace,smelting,petrochemical and so on,need electronic equipment that can work at a higher temperature,especially the development of domestic large aircraft,which needs a lot of high-temperature piezoelectric acceleration The shear type piezoelectric acceleration sensor has high sensitivity and frequency response.The shear type sensor can effectively isolate the base strain.The interference signal from the base is smaller,the test accuracy is higher,and the lateral sensitivity is much smaller than the compression type sensor,which is more suitable for military applications.However,the research on the design theory and method of shear type high-temperature piezoelectric acceleration sensor in China has some shortcomings:the treatment of tangential contact stiffness in the dynamic model is not accurate,and a perfect modeling method of piezoelectric acceleration sensor has not been formed;the research on bolt preload is still in the stage of cause analysis,and the influence of preload on sensor performance has not been analyzed Under high temperature conditions,the appropriate initial preload is determined;the finite element modal analysis is only used to evaluate the performance of the sensor,not to apply the modal analysis method to the optimization design of sensor structural parameters;a perfect design method of shear type high temperature piezoelectric acceleration sensor is not summarized.Due to the shortcomings of these design theories and methods,there is no mature shear piezoelectric acceleration sensor which can withstand the temperature above 800? and meet the requirements of various performances.In this paper,based on the mature research on the compression type high temperature piezoelectric acceleration sensor,the shear type high temperature piezoelectric acceleration sensor is studied from the aspects of bolt preload and contact stiffness research,dynamic modeling,design method and finite element analysis,so as to solve the above problems.This paper analyzes the influence of temperature on the pre tightening force of sensor bolt,deduces the calculation formula of pre tightening force of bolt with different temperature,and obtains the change rule of natural frequency with the pre tightening force of bolt,and obtains the best calculation method of pre tightening force of bolt by combining this rule with the strength calculation formula.The influence of bolt preload on the contact stiffness of the sensor is also analyzed,and the engineering calculation method of tangent contact stiffness is obtained from the empirical formula of normal contact stiffness and the contact parting theory.The method of sensor modeling and the influencing factors of performance are studied.Based on the actual structure of two types of piezoelectric shear acceleration sensor,the force analysis and working mode analysis of the sensor structure are carried out,and the dynamic model building method of the sensor is obtained based on the tangent contact stiffness calculation method.According to the established dynamic model,the influence of structural parameters,materials and temperature on the sensor performance is analyzed,and then the method to improve the sensor performance is obtained,which lays the foundation for the establishment of the sensor design method.On the base of the above research,the design method of shear type high temperature piezoelectric acceleration sensor is summarized from the aspects of sensor structure determination,performance design calculation,insulation resistance design calculation,bolt preload design calculation and strength design calculation.Finally,the performance of the sensor is simulated by finite element method.Taking two types of shear piezoelectric acceleration sensors as examples,the physical three-dimensional model is established,and the appropriate calculation unit and grid division method are determined by using the finite element analysis software.The modal analysis of the sensor is carried out.The influence of the size of piezoelectric sheet,the diameter of bolt rod,the thickness of central column and the size of transition structure on the natural frequency is analyzed,and the structure size is optimized The results provide some guidance for the application of finite element method in the field of sensor optimization design.