Study On High Frequency Dynamic Piezoelectric Pressure Sensor For Shock Wave Measurement

With the development of industry,higher requirements have been put forward for dynamic testing systems of shock wave signal in the fields of aerospace,military and others.Pressure sensors are the important component of dynamic testing systems,and the performance and stability of the testing system are determined.by static and dynamic measurement performance of sensors.Due to the complex manufacturing process and poor thermal stability of piezoresistive pressure sensors,they are less used in the field of projectile shock wave measurement,commonly.Piezoelectric pressure sensors are widely used in the dynamic field such as shock wave measurement due to the high linearity,high sensitivity and wide measurement frequency range.But the key manufacturing and assembly technologies are monopolized by foreign enterprises.In the fields of shock wave measurement and pressure measurement of aerospace engines in China,there is an urgent need for high-frequency dynamic pressure sensors with high sensitivity,high natural frequency and extremely fast response speed.Therefore,in order to break through the technological bottleneck that restricts the field of highfrequency dynamic detection,this article focuses on the measurement of shock wave projectile signals and conducts research on high-frequency dynamic piezoelectric pressure sensors.Firstly,the piezoelectric mechanism of piezoelectric pressure sensor is analyzed,and the piezoelectric constitutive equation is established.The time-frequency characteristics of projectile shock wave signals is analyzed.The performance requirements of high-frequency dynamic piezoelectric pressure sensors are determined.Based on the piezoelectric effect,a high-frequency dynamic piezoelectric pressure sensor with high sensitivity,high linearity,and high natural frequency for shock wave measurement is designed.According to the working environment of the sensor and the results of comparing simulation experiments,the structural scheme of the sensor was determined.At the same time,the influence of different piezoelectric materials on the static and dynamic measurement performance of the sensor is compared and analyzed,and the force sensing components of the sensor are selected.On the basis of analysis of the structure and foundation of high-frequency dynamic piezoelectric sensors,the transmission process of shock wave load signals was studied.Based on the mechanism modelling method,mechanical model of the sensor is established and the theoretical calculation formulas for the voltage sensitivity,charge sensitivity and natural frequency of the sensor is derived.And the effectiveness of the model was verified through ANSYS simulation experiments.Based on the static and dynamic model of the pressure sensor,influence of the structural size parameters of each component of the sensor on its static and dynamic performance is analyzed.Based on the theory of uniform experimental program,an experimental plan for sensor optimization is developed.Experimental data is process with regression analysis,and a regression model for sensor static and dynamic measurements is obtained.the model is imported into MATLAB and genetic algorithm is used to optimize the sensor model.The model is imported into ANSYS for statics,dynamics and piezoelectric coupling analysis,and the structural parameters of the sensor are optimized.Based on the characteristics of high-frequency dynamic piezoelectric pressure sensors,the assembly method of crystal group is studied and the assembly process of the sensor was developed.Based on the negative step principle,a quasi static calibration system for highfrequency dynamic piezoelectric pressure sensors is designed and constructed.the calibration experiment of the sensor is completed and the mapping relationship between the input load and the sensor output voltage is established.Based on the principle of shock tube,the dynamic calibration experiment of the sensor was completed,and the measurement performance indicators of the sensor,such as voltage sensitivity,repeatability,nonlinearity,and natural frequency are obtained.The sensor was applied to the automatic target reporting system for live fire shooting and verified through actual shooting experiments.