基于复小波变换的拉索结构阻尼比识别

采用复小波变换对结构自由响应信号进行分析,推导出信号小波变换的脊线包含结构频率与阻尼比信息;采用动态规划的方法提取小波脊线,用最小二乘拟合方法识别结构固有频率和阻尼比.并对一数值算例信号添加不同噪音进行分析,与对数衰减率法识别结果进行对比,验证了方法的有效性和抗噪性.数值算例结果表明：提出的方法能有效识别结构频率与阻尼比;与对数衰减率法相比,小波方法具有更高的稳定性和抗噪性.将提出的方法用于安装减震器拉索的试验研究,较好地识别出了结构模态频率和阻尼比.

Identifying damping ratio of cable structures using complex wavelet transform

The free response signal of structure was processed using complex wavelet transform.It was deduced that wavelet ridge included the information of structural modal frequencies and damping ratios.The wavelet ridges were extracted by dynamic optimization method,and then the modal frequencies and damping ratios were identified through least square fitting method.A numerical example signal added with different noise was analyzed.By comparing with the identified result of the logarithmic decrement ratio method,the validity and anti-noise was confirmed.The numerical result shows that the proposed method can accurately estimate structural modal frequencies and damping ratios.Compared with the logarithmic decrement ratio method,the wavelet transforms method is more steadied and anti-noised.The addressed method was used in an experimental study on cable structure fixed with shock absorber,and the structural modal frequencies and damping ratios were well identified.