PVDF压力计在相似材料动态力学参数测试中的应用

随着相似材料逐渐用在动力学模型试验中，其动态力学参数的测试和研究显得尤为重要.相似材料是软弱材料，其强度较低，波阻抗也无法与Kolsky杆常用的钢杆或铝杆相匹配，因而无法利用传统的应变测量系统进行动态力学测试.本文基于一维应力波理论，推得被测试件端面应力与应变、应变率之间的关系表达式，进而利用PVDF压电薄膜传感器改进SHPB装置的压力量测方法和系统；采集到相似材料的动态压力信号，得到了相似材料在不同应变率下的全应力应变曲线、动态弹性模量、动态峰值强度以及随速率变化的关系. 

Calibration of PVDF Pressure Gauge and Its Application in Dynamic Parameters Tests of Similar Materials

As similar materials are more and more frequently used in dynamic model tests, it is significant to measure and analyze the dynamic mechanical parameters of similar materials. Since similar material is soft material, its strength is far lower than rock and concrete, and its wave impedance is also much lower than that is Kolsky bar, which is usually made of steel or aluminum. Therefore, it is impracticable to measure the dynamic mechanical parameters by using the traditional strain measurement system. In this paper, the measurement system in SHPB was improved by utilizing the PVDF piezoelectric gauge, which was based on stress wave theory. By using PVDF gauge to directly measure the two ends of specimen, the dynamic parameterswas obtained, including full stress-strain curve, dynamic modulus of elasticity and the dynamic peak intensity, under different strain rates.