结构损伤的出现通常具有空间位置的任意性，使得传统的离散式传感器难以监测损伤的出现和发展，而分布式光纤传感器具有分布式、长距离、精度高和耐久性长等特点为大型复杂结构的分布式探测提供了可能。首先介绍了BOTDA分布式光纤传感技术与应变的关系，并论述了光纤传感器周围结构出现损伤变形时，传感器会监测到应变显著变化这一监测传感特性，然后制作了钢梁的裂缝损伤模型，应用BOTDA分布式光纤传感系统对梁在正常工作状态、单一裂缝和多裂缝工作状态进行了监测。结果显示，在裂缝损伤出现的位置，分布式光纤传感器监测到显著的应变变化，并可以准确定位损伤位置。通过对钢梁的损伤模拟的研究表明，在单一损伤和多损伤情况下，BOTDA光纤传感器可以准确有效的识别钢梁中裂缝的位置，能够实现复杂结构的分布式损伤监测。%Structural damage usually occurs with arbitrary spatial position ,which made it difficult for the traditional dis-crete sensors to monitor the emergence and development of damages ,while the distributed optical fiber sensors offered the possibility for the detection of large and complex architectures ,attributing to its characteristics such as distributablity , long-distance ,high-definition and durability .At first the relationship between BOTDA distributed optical fiber sensing technology and strain were introduced .Then the scenario that when structural damage and deforrmation appeared sur-rounding the optical fiber sensor ,it would monitor significant changes of the strain was dicussed .According to which a steel beam crack damage model was simulated to monitor the beam in normal ,single fracture and multiple fractures work-ing conditions by using BOTDA distributed optical fiber sensors .The results showed that when the crack damage occured , the sensors would monitor significant strain changes ,and accurately locate the damage location .The simulation studies indicate that BOTDA distributed optical fiber sensors can accurately and efficiently identify the location of cracks in steel beams with single and multiple fractures .Therefore ,the distributed damage monitoring of complex structures by using these sensors is feasible .
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