水电能源科学

鉴于传统点式传感器难以实现复杂环境下的长距离输水管道振动的分布式监测和损伤诊断，应用振幅传输模式下的布里渊光时域分析技术(AT-BOTDA),开展了输水管道振动的分布式光纤监测模型试验，提取了输水管道的固有频率和阻尼比，提出了基于分布式光纤动应变传递率的长距离输水管道损伤状态诊断方法。试验结果表明，输水管道损伤会引起固有频率降低、阻尼比升高，且频率和阻尼变化率随损伤程度增大而增大；运用输水管道沿程动应变传递率，可以实现管道损伤的准确定位和损伤程度诊断，比模态参数更具敏感性。由此可见，基于分布式光纤动应变传递率进行长距离输水管道损伤状态诊断切实可行。

In view of the problem that the traditional point sensors are difficult to realize distributed monitoring and damage diagnosis of long-distance water pipeline vibration in complex environments, the Amplitude Transfer-Brillouin Optical Time Domain Analysis(AT-BOTDA) was used to carry out the distributed optical fiber monitoring model test of water pipeline vibration. The natural frequency and damping ratio of water pipeline were extracted, and the long-distance water pipeline damage diagnosis method based on distributed optical fiber dynamic strain transmissibility was proposed. The test results show that the water pipeline damage will cause the decrease of natural frequency and increase of damping ratio, and the frequency and damping change rate increase with the increase of damage degree. Using the dynamic strain transmissibility along the water pipeline can realize the accurate positioning and damage degree diagnosis of pipeline, which is more sensitive than modal parameters. Therefore, it is practicable to diagnose the damage state of long-distance water pipelines based on the distributed optical fiber dynamic strain transmissibility.