Research On Piezoelectric Pressure Sensor For Dynamic Measurement Of Explosion Shock Wave

High frequency dynamic pressure sensor can reflect the whole process of dynamic pressure change,the transient value of important process and the complete waveform signal without distortion.It is one of the main research contents of modern testing technology and widely used in engine transient pressure measurement,explosive mechanics,fluid mechanics and other fields.As a kind of high-frequency dynamic pressure sensor,piezoelectric sensor has the characteristics of good stability,short rise time,high natural frequency and good temperature characteristics,and is often used in fields such as dynamic measurement.In the process of dynamic and transient pressure measurement,piezoelectric sensors are susceptible to the influence of acceleration inertia load caused by vibration,which can easily cause superimposed output and seriously interfere with the waveform signal of normal pressure.At the same time,the influence of various structural parameters of the sensor on its static and dynamic characteristics seriously,in the case where the sensor acceleration sensitivity is eliminated.it is necessary to further improve the static and dynamic characteristics of the sensor to ensure the accuracy of the piezoelectric pressure sensor in the dynamic measurement process.Therefore,the research of piezoelectric pressure sensor for dynamic measurement of explosion shock wave is carried out.Firstly,the source of vibration in explosion shock wave measurement and the cause of acceleration parasitic effect of piezoelectric pressure sensor are analyzed.Through simulation experiments,it is further verified that the piezoelectric pressure sensor will have serious overlapping output when the pressure load and acceleration inertia load act simultaneously.Therefore,the sensitivity of piezoelectric pressure sensor to acceleration inertia load is theoretically deduced.The results show that the parasitic effect of acceleration can be eliminated.Based on this,a piezoelectric pressure sensor with acceleration compensation is designed.Secondly,based on the structure of the sensor,the mechanical model of the sensor is established,and the theoretical formulas for calculating the sensitivity and natural frequency of the sensor are derived.After the validity analysis of the mechanical model of the sensor is completed,the influence of the structural parameters of the sensor on its static and dynamic characteristics is analyzed.Thirdly,the sensitivity of the sensor under pressure and acceleration loads is simulated by finite element software,and the natural frequency of the sensor is obtained by modal analysis and harmonic response analysis.Combined with the theoretical derivation and simulation analysis results,the optimized design of the sensor is completed.The sensor's acceleration sensitivity is eliminated and the static and dynamic characteristics of the sensor are improved.The optimized sensor has a natural frequency of 257 kHz and a charge sensitivity of 4686 pC/MPa.Finally,through the calibration experiment of the sensor,the charge sensitivity of the sensor is 1136 pC/MPa,the natural frequency is 228.3 kHz.the acceleration sensitivity is 0.0244 pC/g,which can eliminate the sensitivity of piezoelectric pressure sensor to the acceleration inertia load.At the same time,the static and dynamic characteristics of the sensor meet the measurement requirements of high-frequency dynamic signals.