PVDF应力测试技术及其在多孔材料爆炸冲击实验中的应用

Stress-testing method by PVDF gauge and its application in explosive test of porous material

通过精确测量Hopkinson杆子弹速度,实现了对PVDF压力传感器的动态标定,测试数据线性度良好,误差不超过1.9%,得到动态灵敏度系数K=32.83pC/N,采用500g TNT对"钢板-泡沫铝-钢板"复合结构进行爆炸冲击加载,测量结构间应力波的传播情况。研究结果表明:电压测试信号可以较为准确地反映弹性波与塑性波的加载时间和传播速度,PVDF对弹性应力波段高频信号的动态响应灵敏准确,与理论数据的相对误差为3.5%。测得泡沫铝材料中塑性波的传播速度为590m/s,A1-B1界面塑性波透射系数达到了0.53,远高于弹性波透射系数。从机理上对应力时程曲线中出现的特殊现象进行了阐述,为相关爆炸测试提供参考。

In this work, by accurately measuring in the dynamic calibration of the PVDF pressure the bullet speed of the Hopkinson bar, we succeeded sensor. The test data obtained have a good linearity and a deviation below 1.9%. The coefficient value K of dynamic sensitivity is 32.83 pC/N. By apply- ing a blast loading of 500 g TNT to the composite structure of ＂steel-aluminum foam-steel＂, the prop- agation of the stress wave between its components was measured. The results show that the voltage signal can accurately represent the loading time and the propagation velocity of the elastic wave and plastic wave and the PVDF dynamic response of elastic stress wave with high-frequency signal is sensi- tive and accurate, with only a relative deviation of less than 3. 5% from the theoretical data. The measured propagation velocity of the plastic wave in the aluminum foam is 590 m/s, the transmission coefficient of the plastic wave in A1-B1 interface is 0.53, which is much higher than that of the elastic wave. Special remarks were made concerning the unusual phenomena observed in the stress curve based upon our understanding of the mechanism, providing a reference for relevant explosion tests.