Design of two-dimensional low-frequency fiber Bragg grating vibration sensor
In order to acquire and monitor the low-frequency vibration signal,a two-dimensional vibration sensor with a symmetrical circular flexure hinge is designed,which can work in the x and z axes.The mech-anical characteristics of the sensing structure are analyzed theoretically.The model is established in Comsol for simulation analysis,and the structure is optimized by finite element method.The hinge resonant fre-quency is designed to be 420 Hz.The fiber Bragg grating is pasted on the surface of the hinge structure as a strain detection device,and the dynamic demodulation of FBG is realized by the edge filter method.The per-formance of the sensor is tested with a standard shaking table.The experimental results show that the natural frequencies of the sensor in the x and z axes both are 420 Hz,the operating frequency range is 20-300 Hz,the average sensitivity in the flat region is 1 847.32 mV/g,and the acceleration resolution is 5.41x10-4 g.The sensor demonstrates a less than 5％lateral interference level in all two-dimensional orientations.The sensor designed in this paper is a two-dimensional vibration sensor,which is suitable for highly sensitive detection of low-frequency vibration signals.
acceleration sensorvibration testFiber Bragg Gratinghinged construction
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