双悬臂梁结构的光纤光栅位移传感器设计

Design of Double Cantilever Beam Fiber Bragg Grating Displacement Sensor

为克服现有光纤光栅位移传感器设计中存在的温度—位移交叉影响、悬臂梁易产生横向偏移等对测量精度的不利影响,提出了一种温度解耦的双悬臂梁式光纤光栅位移传感器。推导传感器的位移测量原理并进行有限元仿真分析,得出梁挠度与位移变化成线性关系。通过对比双悬臂梁不同位置处光纤光栅组合测位移的线性度、灵敏度和重复性误差,结果表明:采用双悬臂梁上表面双向拉伸光栅测量位移时,效果最佳;所设计的光纤光栅位移传感器最大量程可达55mm,灵敏度可达47. 3035pm/mm,最大重复性误差仅为0. 491%,在结构健康监测中具有良好的应用前景。

In order to overcome the negative influence of temperature displacement in cross and transverse movement of cantilever beam on the measurement accuracy of existing Fiber Bragg Grating （FBG） displacement sensors ,a novel decoupling fiber optic grating displacement sensor of double cantilever beam is investigated. The measuring principle of the sensor is deduced and finite element simulation analysis of beam deflection and displacement into a linear relationship is obtained. By comparing the linearity, sensitivity and repeatability error of double cantilever beam at different positions of fiber grating displacement sensor measurement ,the contrast experiments are carried out. Test results show that the fiber optic displacement sensor under upper surface performs best. The maximum range of FBG displacement sensor is up to 55mm,the sensitivity is 47. 3035pm/mm,and the maximum repeatability error is only 0.491%, which have a good prospect in structural health monitoring.