基于光纤布拉格光栅的载荷定位与检测方法

针对传统定位系统存在的结构复杂、实时性低、需要建立训练集等问题,提出利用光纤Bragg光栅结合直角应变花结构的方法对冲击源进行定位。在平面应变下,建立横向效应补偿因子模型和应变解耦模型,证明了光纤布拉格光栅(Fiber Bragg grating,FBG)直角应变花结构用于定位时不受横向效应的影响。同时针对四边简支薄板结构,提出一种判定冲击载荷大小的新方法。通过不同位置两组FBG应变花分别测得的主应变方向,其交点来确定冲击源坐标;通过FBG传感器测得的轴向应变经横向效应补偿,并结合四边简支板扰度曲线和定位坐标,来对冲击载荷大小进行测量。试验表明其定位精度达到2.9 cm以内,定位实时性1 ms左右,冲击载荷大小判定误差在3 N以内。为冲击平台载荷检测提供了一种实用可行的方法。

Load Location and Measurement System Based on Fiber Bragg Grating Sensor

For the problem of complicated structure, low real-time and establishing a training set of traditional positioning system, a rectangular strain rosette structure consists of three fiber Bragg gratings (FBG) is adopted to detect impact load. Under the plane strain, transverse effect correction factor model and the strain of decoupling model are established, which proves that the rectangular strain rosette structure used for localization is not influenced by the transverse effect. At the same time, based on the four edges simply supported plate structure, a novel method is proposed for determining impact load. A principal strain direction of the impact point is respectively measured by two groups of different position of FBG rectangular strain rosette structures, and their intersection point determines the impact source coordinates. Axial strain measured by FBG sensors is compensated by transverse effect correction, which combines with four edges simply supported plate immunity curve and FBG positioning coordinates for determining impact load. Experiments show that the localization accuracy is within 2.9 cm, real-time localization around 1 ms, error of impact load prediction with 3 N. A practical and feasible method is provided for load detection on impact load platform.