高速交通轨道梁高精度光纤变形监测

为了分析长标距光纤光栅（FBG）在轨道梁变形监测中的可靠性问题，建立共轭梁法计算模型，分析跨中挠度的模型误差.引入测量误差，得到不同FBG标距、不同测量误差下长标距FBG的变形监测精度.通过某高速轨道梁的现场测试实验，对长标距FBG的可靠性进行验证，提出2种传感器优化布置方案.结果表明，当布置的传感器数量大于8时，监测结果的误差控制在1%以内，考虑20%的测量误差，监测结果的误差可以控制在10%以内；现场实测的挠度与理论值的相对误差为2.01%，由此说明长标距FBG可以实现对高速交通轨道梁的高精度变形监测.
Abstract: A conjugate beam model was constructed to analyze the theoretical error of mid-span deflection in order to analyze the reliability of the long-gage fiber Bragg grating(FBG)in the deformation monitoring for track girders. Then the measurement error was considered to establish the precision of the long-gage FBG sensors for deformation measurement considering different gage length and measurement error. A field testing on a track girder was conducted to verify the reliability of the long-gage FBG and two optimization programs for the sensor layout was proposed. The identification error can be controlled within 1% when the number of sensor is over 8 and the value becomes 10% considering 20% measurement error. The relative error between the test result and the theoretical value is 2.01%, which indicates that the long-gauge FBG can achieve high precision deformation monitoring for track girders in rapid rail transit.