提出一种反射型极大倾角光纤光栅(ExTFG)悬臂梁振动传感器。从理论上分析ExTFG的弯曲应变特性和振动传感原理,并利用ANSYS构建有限元模型,对传感器进行模态分析和谐振特性响应分析,通过实验研究其在受到周期性载荷下发生弯曲振动的动态响应特性。结果表明:反射型ExTFG悬臂梁振动传感器对加速度连续性激励信号展现出良好的动态响应,可通过调节传感器长度实现其固有频率的改变,在1~5g范围内具有良好的线性响应,其最大加速度灵敏度相对于透射式ExTFG振动传感器提高了约2.5倍, 横电模和横磁模时的最大加速度灵敏度分别达到0.3 V/g和0.26 V/g。此外,该传感器的传感探头尺寸足够小,以ExTFG作为敏感单元,无需额外封装,在实际应用中具有潜在价值。

A vibration sensor based on the reflection-type excessively tilted fiber grating (ExTFG) cantilever is proposed in this work. The bending strain characteristics and vibration sensing principle of ExTFG are theoretically analyzed, and a finite element model is constructed by ANSYS to analyze the modality and resonance characteristic response of the sensor. The dynamic response characteristics of bending vibration of the sensor under the periodic load are studied experimentally. The results show that the vibration sensor based on the reflection-type ExTFG cantilever exhibits a good dynamic response to the acceleration continuous excitation signal. The natural frequency of the sensor can be changed by adjusting its length. The sensor has a good linear response in the range of 1--5g, and its maximum acceleration sensitivity is increased by about 2.5 times compared to the transmission-type ExTFG vibration sensor. The maximum acceleration sensitivity of the transverse electric mode and transverse magnetic mode reaches 0.3 V/g and 0.26 V/g, respectively. In addition, the size of the sensor probe is small enough, and the ExTFG is used as the sensitive unit without additional packaging, so it has potential value in practical applications.