基于应变模态梁型结构损伤识别研究

传统损伤识别方法大多仅限于结构件中单个裂纹的确定,且损伤识别指标无法准确反映早期局部损伤。为此,提出了一种以应变模态差为表征指标的结构表面多裂纹损伤识别方法。首先,依据欧拉伯努利梁理论,建立了含有多裂纹悬臂梁结构传递矩阵方程,得到含裂纹悬臂梁位移模态振型和应变模态振型；其次,计算损伤前后应变模态差并作为损伤识别指标进行识别。以悬臂梁为例,利用MATLAB分别对单损伤和多损伤等不同工况条件进行了模拟仿真,在此基础上,利用PVDF压电传感器进行了单裂纹和双裂纹悬臂梁损伤识别实验。仿真结果和实验结果表明：应变模态差可以对单裂纹与多裂纹损伤工况进行识别，且识别精度高。

Damage Identification Method based on strain mode in beam-like structures

As the traditional damage identification method studied the single crack and the damage identification indexes was not sensitive to the early local damage. A multi-crack damage identification index based on the strain mode for crack identification in beam structure was presented. Firstly, the equation of the transmission matrix of multi-crack cantilever beam based on Euler Bernoulli beam theory were established, the displacement mode and strain mode of the crack cantilever beam were obtained. Secondly, the difference of strain mode was used to identify the damage. Take the cantilever beam for example, the simulation of single damage and multi-injury conditions were carried out with MATLAB , furthermore,the experiment of single crack and double crack damage identification were carried out using PVDF sensors . The simulation results and the experimental results show that the difference of strain mode can be used to identify single crack and multi-crack damage, which has higher recognition accuracy .