轮对损伤诊断的模态分析方法

Modal Analysis Method for Damage Wheelset Diagnosis

应用频率移动及模态振型变化进行结构损伤定位和损伤度诊断的基本原理,对铁路车辆轮对的损伤度进行诊断摸拟分析,用有限元方法得到了轮对卸荷槽附近在不同损伤度的条件下轮对模态频率和位移振幅幅值的变化趋势。分析指出损伤度小时频率移动小,损伤度大时频率移动大,当损伤度由小变大时,位移频率响应的幅值变化比较明显。当损伤度小时亦采用模态振型进行损伤诊断,当损伤度大时亦采用频率进行损伤诊断。

Applying the basic theories of using modal frequency shift and modal vibration change to diagnose the structural damage and the crack position, the authors made a series of simulation for the railway vehicle wheelset; then, the trends of the modal frequency and the displacement amptitude at defferent damage near the unloading groove are obtained with FEM. The analysis shows that small damage result corresponds to small frequency shift, and the big damage the big one, meanwhile, the response amptitude of frequency shift changes obviously in the process. So, when the damage is small, the damage diagnosis is carried out with the means of modal vibration; otherwise, the diagnose is done with the way of frequency shift.