基于光纤光栅增敏传感器的贮箱焊缝应力测试方法

Stress Testing Method for Tank Welding Seam Based on Fiber Grating Sensitive Sensor

摘要:

提出并制备了一种基于光纤布拉格光栅(FBG,Fiber Bragg Grating)的增敏型应变传感器,并对其室温下应变特性进行了实验研究。通过建立传感器件应变传递力学模型,推导出平均应变传递率表达式,并结合传感器件有限元仿真分析设计了双环增敏结构。实验中,将封装后的FBG应变传感器粘贴在等强度梁上进行测试,实验结果表明在0~490με的应变范围内,FBG应变传感器的应变灵敏度达到2.18pm/με,线性度为达0.9914,增敏比为2.59,并采用五点式应变花布设方法对火箭贮箱模型焊缝处进行应变测量,得出焊缝上下两端测试点的主应变灵敏度差值为1.19 με/kg。证明所设计的传感器能够对火箭贮箱模型焊缝处受到的力实现定量分析。

Abstract:

A sensitized strain sensor based on Fiber Bragg Grating (FBG) has been proposed and fabricated, and its strain characteristics at room temperature have been experimentally studied. By establishing a strain transfer mechanical model of the sensor, the expression of the average strain transfer rate is derived, and a double-ring sensitization structure is designed in conjunction with the finite element simulation analysis of the sensor. In the experiment, the packaged FBG strain sensor was pasted on the beam of equal strength. The experimental results show that within the strain range of 0~490με, the strain sensitivity of the FBG strain sensor reaches 2.18pm/με, the linearity is up to 0.9914, and the sensitization ratio is 2.59. The five-point strain rosette method is used to measure the strain at the weld of the rocket storage tank model, and the difference in the principal strain sensitivity of the test points at the upper and lower ends of the weld is 1.19 με/kg. It proves that the designed sensor can quantitatively analyze the force received at the weld of the rocket storage tank model.