环境激励下结构损伤识别广义柔度扰动法

Damage identification with generalized flexibility perturbation method under ambient excitation

提出一种环境激励下检测结构损伤的广义柔度扰动方法,所提方法只需要利用结构振动的少数低阶模态参数,并通过引入振型归一化系数来解决环境激励下不能获得归一化振型的问题。通过对广义柔度扰动方程作适当的变形,并利用矩阵的拉直和广义逆技术,最终可把各单元的损伤参数和振型归一化系数一并予以求解。所提方法不仅能够识别出结构的损伤状况,还能获得振型归一化系数,且理论简单,易于计算机编程实现。算例结果表明:仅采用环境激励下的第一阶模态数据,该方法能够较好地识别出算例结构的损伤状况,且能得到比较精确的振型归一化系数,具有良好的工程应用前景。

A generalized flexibility perturbation approach for structural damage detection was presented here under ambient excitation. By appropriately converting the generalized flexibility perturbation equation, the mass normalization coefficients a structure's first several modal of shapes and the elemental damage parameters were calculated simultaneously using the least-square method. With the proposed approach, not only the damage level of the structure was recognized, but estimates of the mass normalization coefficients also were obtained. The effectiveness of the proposed method was illustrated using the simulated data and the measured noise for an example of a two-storey frame structure. The results showed that the proposed method can be used to identify structural damages accurately only using a structure's first several modal shapes; the predicted mass normalization coefficients of the measured modal shapes with the proposed method have a good accuracy; the proposed procedure is computationally attractive and simple to implement, it is useful for structural damage identification under ambient excitation.