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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 new high-frequency strain testing method using fiber Bragg grating (FBG) sensor is proposed. A high-frequency demodulation system based on the unbalanced Mach-Zehnder interferometer was designed and constructed. A complete test system consists of FBG sensor, high frequency strain generating device and demodulation system composed of three parts. The frequency of the resulting strain signal can be controlled by a dedicated experimental setup, a variant split Split Hopkinson Pressure Bar (SHPB) experimental apparatus widely used to test the mechanical properties of the material. Strain persisting The time is based on the length of the ram with equal elastic impact diameter. The frequency range of the measurable signal of the test system is studied by means of high-frequency vibration signals. Vibration and shock experimental results are given and discussed. The designed system can test the amplitude of dynamic strain in real time. The experimental results show that the system has a good response to the signal under 8kHz.