一种基于新型双轴圆弧铰链的二维FBG加速度传感器

为了实现大跨度桥梁中拉索构件的二维(two-dimensional, 2D)振动信号高精度测量，本文设计并研究了一种小型化的新型2D光纤布拉格光栅(fiber Bragg grating, FBG)加速度传感器，以解决现有FBG加速度传感器体积与质量较大的问题。所设计的FBG加速度传感器主要由含有质量块的双轴圆弧铰链、4个固定支架，以及刻有4段阵列FBG的光纤组成。通过建立FBG加速度传感器的动力学普遍方程，得到灵敏度与固有频率的理论数值，另外辅以Abaqus软件对其进行有限元仿真以验证理论推导的结果。实验测试数据表明，FBG加速度传感器的固有频率约为500 Hz,双FBG的布置使其灵敏度可以达到595.2 pm/g,此外对称推挽的圆弧铰链设计还具有优异的横向抗干扰和温度自补偿性能。最后以某中承式钢管混凝土拱桥为实际工程案例，使用所设计的2D FBG加速度传感器实现了吊索索力的有效测量。

A 2D fiber Bragg grating accelerometer based on a novel biaxial arc hinge

In order to realize the high-precision measurement of the two-dimensional (2D) vibration signal of the cable components in the long-span bridge, and to solve the problem of the large volume and mass of the existing fiber Bragg grating (FBG) accelerometer,a new miniaturized 2D FBG accelerometer is designed and studied in this paper.The designed FBG accelerometer is mainly composed of a biaxial arc hinge with a mass block,four fixed brackets,and an optical fiber engraved with four-segment array FBGs.By establishing the general dynamic equation of FBG accelerometer,the theoretical values of sensitivity and natural frequency are obtained. In addition,it is supplemented by Abaqus to carry out finite element simulation to verify the theoretical derivation results.The experimental test data show that the natural frequency of the FBG accelerometer is about 500 Hz.The arrangement of the dual FBGs allows the sensitivity to reach 595.2 pm/g.In addition,the symmetrical push-pull arc hinge design also has excellent lateral anti-interference and temperature self-compensation performance.Finally,taking a middle-supported concrete-filled steel tube arch bridge as an actual engineering case,the designed 2D FBG accelerometer is used to effectively measure the cable force of the sling.