基于第二代小波变换的结构损伤识别

Research of structural damage identification based on the second generation wavelet transform

利用第二代小波分解对信号突变信息敏感的特性,将结构动力响应信号分解为多个小波组分信号,通过各组分信号小波能量变化和小波能量变化率确定损伤位置和识别结构损伤,提出基于第二代小波能量变化率指标的结构损伤识别方法。研究结果表明:第二代小波能量变化率对结构损伤比较敏感,其幅值与置信上限之差远高于其它测点,可以用来判定结构损伤位置;但噪声对损伤识别的影响较大,在实用中应先对现场采取的动态信号进行降噪处理,再应用第二代小波能量变化率指标对结构进行损伤识别,可较好地识别出结构的损伤位置。

Employed the sensitivity of the second generation wavelet analysis to breaking information of signal, a new structural damage identification method based on the energy change rate indes was proposed by decomposing the structural response signal into multiple signal of wavelet components, determining the damage location and identifying the degree of structural damage through the enery change and its change rate of each wavelet components. Numerical simulation indicates that the change rate of second generation wavelet energy is sensitive to the structure damage. The difference between it＇s amplitude and upper confidence limits at structure damage loca- tion is much bigger than any other measuring points, which means it can be used to locate structure damage. But the identification result is obviously affected by noise, so when this method is employed in practical engineering, the noise in dynamic signal taken on - site must be firstly reduced, and then the second generation wavelet energy change rate indicators are adopted to indentify structural damage, which can locate damage well.