Shunt capacitor array shock wave position sensor

Abstract

The position of the shock wave front under an impact load can reveal many material properties. A design of a shunt capacitive shock wave position sensor has been investigated in this work, utilizing a series of electric probes connected to the shunt capacitor array to measure the moment when the shock wave front reaches a specific point on the sample, which can be used to determine the shock wave front's evolution law. Using the Simulink module in MATLAB software, a sensor circuit model was designed and simulated, and the influence of various conditions on the output signal's falling edge relaxation times were investigated. The results indicate that the relaxation times initially increase, then gradually flatten out, after that, when electrical probes are progressively triggered, the relaxation times will increase again. The relaxation time increase with the rising capacitance, self-inductance coefficient, and voltage drop, and it decrease with increasing coupling coefficient. In addition, it initially decreases and then increase as the initial output voltage increases. Comparing the output signals of the traditional series resistance shock wave position sensor under the same general parameters, it reveals that the voltage falling edge relaxation times for each stage of the sensor are in the order of 10−10 s magnitude, much smaller than the 10−8 s magnitude of the latter, indicating higher measurement accuracy for the sensor. In this work, it also provides a reliable theoretical basis for selecting circuit parameters of the shunt capacitor shock position sensor in experiments by simulation.