小波变换在横向裂纹转子升速过程状态监测中的应用

APPLICATION OF WAVELET TRANSFORM IN THE CONDITION MONITORING OF CRACKED ROTOR DURING STARTUP PORCESS

起停机过程中振动特征的提取及其识别对于旋转机械故障诊断是极其重要的。该文用数值积分方法求解含有横向裂纹的Jeffcott转子模型在转子升速过程中的动态响应,并对其进行小波变换,最后用时频等高图来表示小波变换系数。结果表明小波时频等高图不仅能表示升速过程中横向振动各振动分量的能量组成情况,而且也显示了各振动分量的变化趋势,完整而直观地展现了整个升速过程,充分地提取了裂纹转子在升速过程中的特征,为实际旋转机械的振动故障诊断提供了依据。

Extraction and identification of the vibration features in the process of start up or run down are very important for the fault diagnosis of rotating machinery. In this paper a simple Jeffcott rotor with a transverse crack was considered. Using numerical integration, the dynamic responses of the rotor model during the start up process were evaluated. The lateral responses were transformed with the Morlet wavelet. The transform results were plotted in a contour map which is so-called time-frequency contour map. The results indicate that the contour map not only shows the energy distribution of the responses, but also the trend of every overtone composing the responses. Since the contour map presents the process of start up entirely, it can extract enough characteristics for the vibration fault diagnosis of rotating machinery.