光纤Bragg光栅用于高频应变测试的研究(英文)

Fiber Bragg grating sensor for high frequency strain measurement

提出了一种传感部分采用光纤Bragg光栅(Fiber Bragg grating,FBG)传感器的高频应变测试新方法。设计并构建了基于非平衡马赫-曾德(Mach-Zehnder)干涉仪的高频解调系统。完整的测试系统由FBG传感器、高频应变产生装置和解调系统三部分组成。所产生的应变信号的频率可以通过专门的实验装置来控制,这是一种广泛用于测试材料机械性能的变形分离式霍布金逊压杆(Split Hopkinson PressureBar,SHPB)实验装置,应变持续的时间根据与撞击弹性等径的冲锤长度计算。借助高频振动信号研究了测试系统可测信号的频率范围。给出了振动和冲击实验结果,并进行了讨论。所设计的系统可以实时测试动态应变的幅值,实验结果表明,该系统对频率为8kHz以下的信号具有好的响应。

A novel scheme for measurement of high-frequency strain is presented. The strain measurement system is made up of Fiber Bragg Grating（FBG） sensor, high-frequency strain signal source and demodulation part. The high frequency demodulation system of FBG is designed based on unbalanced Mach-Zehnder interferometer. The frequency of strain signal can be controlled by a special experimental setup, which is a kind of modified Split Hopkinson Pressure Bar（SHPB） used widely for testing physical properties of materials. The lasting time of strain is calculated according to the length of an elastic piston. It has the same section with impacted elastic bar. Operating frequency range of the measurement system is studied using vibration signal. Experimental results of vibration and impact are shown and discussed. The system can measure amplitude of dynamic strain in real time. Experiment results demonstrate that the measurement system has good frequency response within 8kHz.