基于PVDF传感器的单脉冲激光推力加载过程研究

Pulse thrust loading process based on PVDF sensor

利用高频响应材料PVDF作为敏感元件,建立了一套单脉冲瞬态推力测试系统,并用φ37mm分离式Hopkinson压杆装置对该测试系统进行动态标定。标定结果显示,在0-150MPa范围内,PVDF传感器（5mm×5mm）的压电特性呈线性,动态压电系数经线性拟合后为20pC/N。用所建推力测试系统获得了单脉冲激光作用下,旋转抛物形激光推力器的推力加载曲线,并对该曲线形成多个峰值的原因进行了分析。实验结果表明,该系统可以捕获激光推力器脉冲推力加载特征。

The paper presents a system to measure pulse instantaneous thrust using PVDF, which can respond to high frequency signal, as the sensitive element. System calibration is completed using separate Hopkinson pressure bars（SHPB） whose diameter is 37 mm. Result of calibration shows that piezoelectric characteristic of PVDF （5 mm×5 mm） is linear if the pressure is lower than 150 MPa. Piezoelectric coefficient of PVDF is about 20 pC/N after the calibrated data fitting. Thrust loading curve of parabolic laser thruster impacted by single pulse is acquired and the peak values of thrust are analyzed. Experimental results indicate that this test system can capture the characteristics of thrust loading and it is valuable for investigating laser thrusters and pulse detonation engines.