Abstract:

A novel adaptive modal parameter identification method based on modified Morlet continuous wavelet transform(MCWT) was proposed to improve the modal parameter identification precision. In MCWT,a modified operator was applied to adjust the band wide of the mother wavelet to improve the resolution in frequency domain. The proposed principle of maximum-energy (PME),and the principle of maximum-distance(PMD)/minimum-relativity (PMR) of continuous wavelet decomposition of the close scales were adopted to ascertain optimal decomposed scale of wavelet.Simultaneously, different anti-repeat operators were applied into target function to eliminate the coupling of the decomposed signals at the most extends.A simulation and an experiment were carried out on a simple supported beam,the results validate the proposed method.

Key words: modified Morlet wavelet, adaptive, modal analysis, parameter identification

摘要：

提出了一种修正的Morlet小波自适应结构模态参数识别方法，选取Morlet小波作为母小波，并引入一个调整因子N根据信号的特征对母小波的带宽进行调整。提出了能量极大值原则，结合相邻尺度小波分解的距离最大原则和相关系数最小原则，自适应地选择最佳小波分解尺度。数值仿真证明了该方法对密集模态进行解耦的有效性。将所提方法应用于一个简支梁的模态分析，实验结果表明，提出的自适应模态参数识别方法降低了模态参数识别的难度，提高了模态频率和阻尼比的识别精度。

关键词: 修正的Morlet小波, 自适应, 模态分析, 参数识别