Temperature compensation of a PVDF stress sensor and its application in the test of gun propellant charge compression stress

Due to the randomness and transiency of the compressional movement of the gun propellant charge, polyvinylidene fluoride (PVDF) film with easy processing and a high frequency response is used as a test unit of the PVDF stress sensor. The sensor is often used at the same ambient temperature as the gun propellant charge, and its accuracy is susceptible to temperature. The temperature test of the PVDF stress sensor was carried out to obtain the pyroelectric effect and mechanical response in the range of −40 °C to 30 °C. The response time of the pyroelectric effect is much longer than the action time of the compression stress, so the pyroelectric effect can be ignored in the compression stress test. The least squares support vector machine (LS-SVM) method is used to process the test data of the mechanical response in the range of −40 °C to 30 °C, and the LS-SVM model is established to obtain the input force with compensation, which improves the test accuracy of the sensor. A PVDF stress sensor and a dynamic compression device of the gun propellant charge were used to test the compression stress of the gun propellant charge. The compensated compression stress was obtained according to the LS-SVM model established by the temperature test, and the error with the standard sensor test result is small. The new method used in this paper can effectively solve the effect of temperature on the PVDF stress sensor during the compression stress test of the gun propellant charge. (paper)