基于小波包分析的拉索损伤声发射信号特征提取

结合显式有限元和小波包分析技术开展了拉索损伤声发射信号特征提取的仿真分析。采用ANSYS/LS-DYNA模拟得到拉索损伤声发射信号的仿真信号,基于小波包能量谱对拉索声发射的有限元仿真信号进行了特征提取,从小波包分解层次、特征频带数量的选择及特征参数的噪声鲁棒性三个方面开展了讨论分析。结果表明:(1)通过选择适当的小波包分解层次,小波包能量谱可以精细地反映信号的特征;(2)选取少数特征频带就能使得小波包能量谱反映声发射信号的特征信息;(3)基于小波包能量谱的特征参数具有良好的损伤敏感性及噪声鲁棒性,能在强噪声影响下实现对拉索不同损伤类型的判别。

Feature extraction of acoustic emission signals for cable damage based on wavelet packet analysis

The simulation Analysis of feature extraction of acoustic emission signals for the damage of cables is presented on the basis of the combination of explicit finite element method and wavelet packet analysis. The wavelet packet energy spectrum is used to extract the features of acoustic emission signals, which are simulated by using the program of ANSYS/LS-DYNA. The feature extraction is discussed from the aspects of decomposition level, number of the selected feature bands and noise robustness of the feature parameters. The results show that (i) the wavelet packet energy spectrum can reflect the feature of the signals finely when proper decomposition level is chosen; (ii) only a minority of the feature bonds can make the wavelet packet energy spectrum reflect the feature information of acoustic emission signals; (iii) the feature parameters established based on wavelet packet energy spectrum indicate the preferable damage sensitivity and noise robusticity and the discrimination of various damage types can be realized with high levels of noise.