改进的小波包能量指标在结构损伤识别中的应用
Application of Improved Wavelet Packets Index to Structural Damage Detection

小波包分析采用时域和频域结合的方法对振动信号进行分析,在时频两域都具有表征信号局部特征的能力。大量研究成果表明小波包能量和模态柔度都对局部损伤变化非常敏感,通过离散小波包分解对冲击荷载作用下结构振动响应加速度信号进行各频带的分解与重构,在模态柔度曲率差思想的基础上,定义相对小波能量柔度曲率差损伤指标,对损伤进行定位。通过连续梁的数值模拟及连续梁的试验验证,并与仅基于相对小波包能量曲率差的方法进行比较,进一步说明该方法的可行性。
The wavelet transform may present the local properties of signal in time-frequency domain,it can zoom up and recognize the mutation signal of structural response under different scales. Numerous studies show both wavelet energy and flexibility curvature are very sensitive to local structural damage. Based on discrete wavelet decomposition, the signal under impact load can be decomposed to different frequency range and reconstructed. This paper presents a new damage index based on discrete wavelet decomposition and modal analysis. Through numerical analysis and experiments of a continuous beam,the results show that the proposed method is effective