摩擦振动的时频特性

TIME-FREQUENCY CHARACTERISTICS OF FRICTION-INDUCED VIBRATION

采用短时傅里叶变换(Short-time Fourier transform,STFT)和Zhao-Atlas-Marks分布(ZAMD)这两种时频分析技术对往复滑动条件下的摩擦振动时频特性进行研究。用例子探讨了这两种时频分析技术的特点,联合采用STFT 和ZAMD方法可得到较高的时频分辨率。对摩擦振动信号的时频特性研究表明,摩擦振动的频率从其初始形成到消失的全过程中基本没有发生变化,这个特性显示在摩擦振动的形成和消失过程中没有遇到结构非线性因素。还讨论了时频不变特性的物理意义,指出用模态耦合理论不能满意地解释摩擦振动有限和消失现象。

Short-time Fourier transform （STFT） and ZhaoAtlas-Marks distribution （ZAMD） are applied to analyze timefrequency characteristics of friction-induced vibration. STFT and ZAMD are synthetically used to obtain better the identifying accuracy of the frequencies of vibration signals. Special emphasis is placed on an analysis of the process from initial formation to disappearance of friction-induced vibration. The result shows that the friction-induced vibration is stationary during the whole process from its initial generation to disappearance. It suggests that no nonlinear factor is involved during the formation and disappearance of frictioninduced vibration. The physical phenomenon correlated with this characteristic is also discussed. This unchanging timefrequency representation does not appear to support the modal coupling mechanism of friction-induced vibration generation.