基于PVDF传感器的固体推进剂冲击应力测量

Measurement of the Impact Stress of Solid Propellant Based on PVDF Sensors

为了测量高速冲击下固体推进剂的应力水平,设计搭建了一套基于PVDF压电膜传感器的应力测量系统;采用分离式Hopkinson压杆对其进行标定,应用有限元软件分析计算了落锤试验中推进剂表面受到的平均应力;对比了推进剂落锤试验实际采集的应力信息,得到了落高和应力的关系曲线。结果表明,所采用的PVDF压电膜通过SHPB标定后得到其压电常数为9.7pC/N;搭建的应力测量系统能满足高速冲击试验的相关需求,应力与电压值满足σ=130 U关系式;推进剂落锤试验与有限元计算结果显示推进剂受到的最大应力与落高的0.5次方成正比。

To measure the stress level of solid propellant under high speed impact,a set of stress measurement system based on PVDF piezoelectric film sensor was designed and built.The separated Hopkinson pressure bar was used for calibration.The finite element analysis software was used to analyze and calculate average stress of propellant surface in the drop hammer test.The actual stress information collected in the drop hammer test of propellant was compared.The relation curve of drop height and stress was obtained.The results show that the piezoelectric constant of PVDF piezoelectric film sensor obtained after calibration by SHPB is 9.7pC/N.The established measurement system can meet the relevant requirements of high-speed impact test.The stress and voltage satisfy the relation formulaσ=130 U.The results of drop hammer test and finite element simulation of propellant reveal that the maximum stress subjected on the propellant is proportional to 0.5 square of drop height.