Research On Dynamic Response Of Piezoelectric Impact Sensor

The advancement of modern engineering technology is inseparable from the rapid development of sensor technology.As a device used in extreme environments,piezoelectric impact sensors have higher and higher requirements for their performance.However,sensors with higher accuracy in static testing have large errors when using statically calibrated data for dynamic testing.The piezoelectric properties of piezoelectric ceramics under impact loads directly affect the response characteristics of piezoelectric impact sensors.The previous analysis and application are almost based on the static characteristics of piezoelectric ceramics.More and more studies have pointed out that piezoelectric ceramics under large loads exhibit significant nonlinear characteristics,especially for piezoelectric impact sensors used in extreme environments.Correct understanding of the piezoelectric properties of piezoelectric ceramics under impact loads is very important for understanding the dynamic response characteristics of piezoelectric impact sensors.In this paper,dynamic response of the piezoelectric impact sensor is studied through experiments and numerical simulations,including the following aspects:The mechanical and electrical response characteristics of piezoelectric ceramics at different loading speeds were tested by SHPB experimental technique.The changes of stress,strain and charge were analyzed.The results show that the piezoelectric properties of piezoelectric ceramics under impact loads have significant rate correlation.With the increase of the loading speed,the ability of the piezoelectric ceramics to generate electric charge in the unloading section is gradually reduced.The reason may be that the piezoelectric ceramics have a certain degree of damage during the loading process;during the impact loading,the piezoelectric strain constant of the piezoelectric ceramics d33 will change.And greater than the quasi-static measurement results,as the loading speed increases,d33 has a tendency to gradually increase.According to the HJC constitutive model commonly used in ceramics materials,the parameters required for the HJC model were determined by numerical experiments based on experimental results and literature data.The mechanical response characteristics of piezoelectric ceramics at different loading speeds were simulated and compared with the SHPB experimental results.The comparative analysis shows that the HJC model can simulate the mechanical behavior of piezoelectric ceramics under impact load in a certain range.The frequency response characteristics of a certain type of piezoelectric impact acceleration sensor were tested.Then,through the drop weight test,the output characteristics of the piezoelectric impact sensor under different drop heights were studied.With the increase of the drop height,the maximum charge of the sensor output is approximated.The linearity increases,and as the filter frequency gradually decreases,the maximum charge at the same drop height gradually decreases.The HJC model was applied to the piezoelectric ceramics,and the response of the piezoelectric impact sensor was simulated.The simulation results of the piezoelectric impact sensor were corrected according to the variation law of the piezoelectric strain constant obtained by the SHPB experiment,and compared with the drop hammer experiment.The results show that the modified simulation results are in good agreement with the experiment.