基于光纤Bragg光栅的古建筑结构健康监测技术研究∗

摘要

Ancient architecture has the great value of history,culture,art and science research. A structural health monitoring system for ancient architecture was designed, which combined M-Z interferometer demodulation technique based on 3×3 coupler and LabVIEW. It realizes the functions of data collection from interferometer,pro-cessing,storage,waveform display,variation tracking display,spectral analysis and warning. The system can not only avoid the influence of change of light source intensity and interference fringe contrast on the measurement results, but also has the advantages of simple operation,low equipment cost. The experiment of fiber Bragg grating strain sensor was designed to test system performance. The results show a good linear relationship between phase change and strain,the measurement error is 1.4%.%古建筑具有极其宝贵的历史、文化、艺术和科学研究价值。通过基于3×3耦合器的M-Z干涉解调技术和LabVIEW相结合的方法，设计了古建筑结构健康监测系统，实现了干涉仪信号的采集、处理、保存、波形显示和变化量的跟踪显示、频谱分析、预警等功能，不仅能够避免光源强度与干涉条纹对比度变化对测量结果的影响，而且操作简单，设备成本低。设计了光纤光栅应变传感实验测试系统性能，结果表明相位变化与应变呈良好的线性关系，测量误差为1.4%。