基于连续小波变换的时变结构瞬时模态参数识别

为体现时变结构动力特性,定义随机冲击荷载作为时变结构输入激励,提出了基于连续小波变换的时变结构瞬时模态参数识别方法。在短时时变假定条件下,建立基于模局部极大值的连续小波变换时变参数识别原理,利用结构的输出响应进行瞬时模态参数识别,采用三自由度的时变结构体系进行数值模拟,该方法能够准确识别时变结构的瞬时模态参数值。通过设计具有质量参数可变的两层钢框架模型进行测试,验证了方法的有效性与可行性。

Instantaneous Modal Parameter Identification of Time-varying Structures Based on Continuous Wavelet Transform

In this paper, we propose a method for identifying the instantaneous modal parameters of a time-varying structure based on a continuous wavelet transform. First, we selected a random impact load as the input excitation of a time-varying structure. Then, under the assumed time-varying condition in a short time span, we established a principle for identifying the time-varying parameter based on the continuous wavelet transform. We identified the instantaneous modal parameter using only the output response of the structure, and performed a numerical simulation of a 3-DOF time-varying structure system. The results show that this method can accurately identify the instantaneous modal parameter of a time-varying structure. Finally, we designed and tested a two-layer steel frame model with variable quality parameters, and the results further verified the validity and feasibility of the proposed method.