布里渊光时域反射技术应用于模型实验测试的研究

Study of Brillouin Optical Time-domain Reflectometer Applied to Model Experimental Test

布里渊光时域反射技术凭借其体积小、结构效应低、数据采集效率高等优点在模型试验中应用具有较大的优势。针对布里渊光时域反射技术(Brillouin optical time-domain reflectometer,BOTDR)应用于模型试验中存在距离分辨率相对较大的问题设计了试验,考虑光纤位置约束影响因素定义光纤空间密度,研究光纤布设长度、类型、植入密度对测试结果的影响。研究结果表明:当试块内部传感光纤长度小于其应变采集仪的距离分辨率时,监测到的结果很难反映应试块实际应变情况;当试块内部光纤长度大于光纤应变采集仪分辨率时,随着试块内部光纤长度的增加,相对应变离散度逐渐降低,但同时也受到光纤布设方式的影响;随着光纤植入长度的增大和光纤空间密度的增大,试块开裂荷载呈现出先增大后减小的趋势。

Distributed optical-fiber sensing technology has great advantages in model tests due to its smaller size,lower structural effect,and higher data acquisition efficiency.In this paper,aiming at the problem of relatively large distance resolution in the application of Brillouin optical time-domain reflectometer technology(BOTDR)in the model test,an experiment was designed.Considering the influence factors of fiber position constraint,the spatial density of optical fiber was defined,and the influence of fiber layout length,type and implantation density on the test results is studied.Results show that when the length of the monitoring fiber inside the test block was less than the distance resolution of the BOTDR,the observed results can hardly reflect the actual strain of the test block.When the length of the monitoring fiber inside the test block was greater than the distance resolution of the BOTDR,as the length of the fiber inside the test block increased,the relative strain dispersion gradually decreased,but it was also affected by the way the fiber was laid.With increases in the length of the implanted fiber and in the spatial density of the fiber,the cracking load of the test block increased first and then decreased.