结构时变模态参数辨识的时频分析方法

应用线性和二次时频变换方法，即短时傅里叶变换和魏格纳—维尔分布，进行了时变结构模态参数的辨识．通过对刚度突变和刚度连续变化的单自由度系统时变参数辨识的仿真，论述了两种时频辨识方法的特点．仿真结果表明，时频变换辨识方法是辨识时变模态参数的有效工具，而且魏格纳—维尔分布二次时频表示能得到比基于短时傅里叶变换的谱图更好的辨识结果．

Time-Varying Modal Parameter Identification with Time-Frequency Analysis Methods

Two schemes of time frequency representation were developed and implemented to identify the time varying modal frequencies of single degree of freedom system with changing stiffness. This study explored the relationship between the spectrograms based on short time Fourier transformation (STFT) and the Wigner Vill distribution (WVD). The characteristics of those two kinds of time frequency representations were analyzed. To assess the validation of those time frequency analysis methods to identify time varying modal parameters, two simulated stiffness changing single degree of freedom systems were used to identify time varying modal frequencies. The simulated results indicate that the time frequency analysis method is an effective tool for identifying time varying modal parameters.