基于光纤光栅的T形节点结构损伤识别

T形加强筋是船体主要强度件,介绍了T形节点结构在船体结构稳定性上的关键作用;分析了光纤光栅传感器的独特优点,推导了光纤光栅应变传感原理;根据T形节点结构特点,搭建了一套基于光纤光栅应变传感网络的结构损伤识别系统;构建了T形节点结构的两种不同损伤状态,运用不同载荷作用下结构应变值变化趋势直接判断了损伤存在性和损伤位置;对传感网络的应变值进行归一化处理,结合支持向量机算法识别了T形节点结构的损伤程度,其最大识别偏差为3.43%;实验结果表明光纤光栅传感网络在大型复杂结构健康监测中具有广泛的应用前景。

Damage identification in T-joint structure with Fiber Bragg Grating

As the main strengthening part of the ship structure,the key role of T-joint structures in the stability of ship hull is introduced.The unique advantages of Fiber Bragg Grating sensor are analyzed,such as small size,corrosion resistance,anti-electromagnetic interference,easy to build sensor network etc.The work principle of Fiber Bragg Grating is also introduced.A structural damage identification system has been set up with Fiber Bragg Grating strain sensor network according to the T-joint structure characteristic.Two kinds of damage case of T-joint structure were designed,and the damage existence and damage location of T-joint structure were directly identified by the strain variation trendency under different loads.After the strain values′ normalization processing and being input to the support vector machine,the damage degree were intelligently identified with support vector machine algorithm.It shows that the identification error is 3.43%.From the experimental results,it can be seen that the Fiber Bragg Grating sensor network has a wide application prospect in the structural health monitoring for large and complex structures.