基于小波奇异性的梁结构损伤诊断

利用小波奇异性检测原理,采用墨西哥草帽小波对结构在健康和损伤状态下的模态振型差进行小波变换。根据模态曲率进行损伤检测的原理,提出了表示损伤位置的指标,指标值极大处即损伤发生的位置。以一个悬臂梁损伤检测为例,进行了数值模拟和实验分析。数值模拟结果表明该指标能准确的对损伤位置进行诊断,并根据指标模极大,讨论了Lipschitz指数与损伤程度的关系。

A BEAM DAMAGE DIAGNOSIS BASED ON WAVELET SINGULARITY

The continuous wavelet transform (CWT) by a Mexican hat wavelet having two vanishing moments is applied to the first mode shape difference of a structure under the health and damage state. A damage index is presented based on the wavelet singularity detection theory and mode curvature conception, and the damage location is detected by the maximum of the index. To test the effectiveness of the proposed method, numerical simulation and experiment analysis are performed on a cantilever beam. Numerical simulation results show that the index can exactly detect the location of the damage. The relation between Lipschitz exponent and damage extent is analyzed based on the index maximum.