柱壳结构损伤识别方法

摘 要:对柱壳结构的损伤部位和程度进行识别是柱壳结构进行安全性评定的一个重要环节。本文对柱壳结构损伤前后动力特性进行了分析，采用摄动法推导了由于单元损伤引起的各阶模态振型改变系数；推导了模态应变能变化与单元损伤之间的关系；采用单元模态应变能的变化率作为柱壳结构损伤诊断的标识量，证明了单元模态应变化率对损伤的敏感性。对柱壳结构损伤识别方法进行了研究，所提出的方法仅需要量测的低阶模态信息和刚度矩阵就能完成结构的损伤识别。最后，以一混凝土柱壳结构为工程实例，对其在不同损伤情况下的损伤进行了分析，结果表明，所提出的损伤识别方法能够很好地识别不同损伤组合下的损伤部位和程度，同时能较好地识别结构小损伤，因而证明了本文所提出的方法的正确性和有效性。 关键词:柱壳结构；损伤识别；动力特性；损伤标识量；模态应变能

Damage Detection Method of Cylindrical Shell Structures

Abstract: The damage position and degree detection of cylindrical shell structure is an important link in safety evaluation of cylindrical shell structure. The dynamic properties of structure before and after damage were analyzed, and the change coefficients of modal shape were deduced from element damage using perturbation method. The relation between variation of modal strain energy (MSE) and damage of element was deduced. The variation rate of modal strain energy was taken as the signature for damage diagnosis, and it was proved that the element of modal strain rate was sensitive to damage. The method of damage detection of cylindrical shell structure was studied, which only needs low measured modal information and stiffness matrix before damage. Finally, a concrete cylindrical shell structure was studied as an example. Calculation results under different damage situations are analyzed. It is seen that the proposed method can identify the damage situation and degree under different combined damage situations. The method can also identify small damage correctly. Therefore, the method is proved to be accurate and effective.