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Real-time vibration monitoring system of thin-walled structures' health status based on the self-mixing effect

In this paper, a simple structure, low-cost all-fiber laser self-mixing vibration sensing system is designed for monitoring the health status of thin-walled structures which are workpieces in machining, for resolving the interferential problems with the existing vibration measurement system, caused by the cruel environment such as electromagnetic interference, humidity. In this system, a distributed feedback all-fiber laser with ultra-short cavity length is used as the light source, and the real-time monitoring of vibration state of plate under different positions of forced vibration sources is observed. The experimental results show that when the forced vibration source located at the free end or the restricted end of the plate, the measurable self-mixing signals (signal-to-noise ratio up to 30dB) is available at any position. Moreover, it will help us to analysis the specification and the physical mechanism of the forced vibration, by studying this all-fiber laser self-mixing vibration sensor in detail.