基于FBG的复杂面形应变场检测系统研究

Research on strain field detection system for complex surface based on FBG

为了实时采集在受力条件下复杂面形的应变分布,为复杂面形结构的健康程度评估提供数据支撑,设计了一种基于光纤传感网络的复杂面形应变分布实时检测系统。系统由光纤激光器、耦合器、解调仪、光纤传感阵列组成,采用与光学扫描检测数据对比的方法,进行了多种不同施力条件下待测件应变分布的理论分析和仿真计算;实验中采用4组光纤光栅传感器在待测面上正交排布的形式,针对5.0mm铝板进行了测试,并与仿真数据进行了对比。结果表明,应变分布与施力位置、大小、表面结构均有关;实验测得最大波长偏移量为1.324nm,2.547nm和1.643nm,其分别对应的位移偏移量为0.244mm,0.523mm和0.347mm,与激光扫描法标定数据对比,相对均小于10%。该测试数据能够反映面形变化趋势,符合设计要求。

In order to collect the real-time strain distribution of complex surface shapes,and provide data support for the health assessment of complex surface structures,the strain field detection system for complex surface was designed with fiber-optic sensor network.The system consisted of a fiber laser,a coupler,a demodulator,and a fiber sensing array.The method was compared with the optical scanning detection data,and the theoretical analysis and simulation calculation of the strain distribution were carried out under many different conditions.The strain distribution of the device under test with a variety of different force conditions was simulated and analyzed.The results show that the strain distribution is related to the applied position,size and surface structure.A 5.0mm aluminum plate was tested and compared with simulation data in the experiment.Four groups of fiber grating sensors were placed on the surface to be measured in an orthogonal structure arrangement.The test results show that the maximum wavelength offsets are 1.324nm,2.547nm,and 1.643nm,and the corresponding shift offsets are 0.244mm,0.523mm,and 0.347mm,respectively.Compared with the calibration data of laser scanning method,the offset of this method is relatively less than 10%.The test data can reflect the trend of surface shape change,and it meets the design requirements.