光纤光栅型智能结构损伤识别的小波包分析

基于结构振动监测技术,采用小波包分析方法对采集的结构振动信号进行了小波分解。介绍了小波包分解技术,提出将小波包能量谱作为损伤指标用以表征结构的损伤状态。在相同损伤位置不同损伤程度、不同损伤位置相同损伤程度的两种情况下对试件进行了六种不同损伤工况的振动信号分析。数据分析结果表明,结构的损伤将导致结构振动信号小波包分解中特定阶数的能量增加,而所提出的损伤指标对结构的损伤程度、损伤距离及损伤位置与光栅传感器之间的角度均敏感,实验中能够识别12 g重物且距离光纤光栅传感器30 cm的损伤,表明对智能结构的在线损伤识别是可行的。

Damage diagnosis for optical fiber grating smart structure based on wavelet packet analysis

To realize the damage diagnosis of a optical fiber grating smart structure, the structual dynamic response signal was decomposed with the wavelet analysis method based on the vibration moni- tor of optical fiber grating smart structure. The wavelet packet decomposition was introduced, and the wavelet packet energy spectrum describing the damage character was used to identify the structual damage status. Then, six different damage circs were studied by experimental laminates, inculding the different degrees and the same location of structure damage, and different locations and the same degree of structure damage. The results show that the structure damage will lead to the increase of wavelet energy spectrum of some specifically frequency bands of the structure dynamic response signal, and the damage characters are sensitive to the damage degree, damage location and the degree from the damage to the sensor. In the experiment, this method can recognize the damage of 12 g weights and 30 cm from the optical fiber grating sensor, it is feasible to realize the structure on-line damage diagnosis.