基于疲劳损伤谱的转向架设备振动载荷谱编制研究

Research on Compiling Vibration Load Spectrum of Equipment mounted on Bogie Frame Based on Fatigue Damage Spectrum

轨道车辆转向架设备服役环境复杂多变,编制合适的振动载荷谱对结构可靠性设计具有重要意义。目前,通常基于实测振动载荷能量值或特定运行条件下平稳高斯振动载荷编制设备载荷谱(以功率谱密度形式表征),但这与设备实际承受的非平稳振动载荷不具有等损伤能力。因此,提出一种基于疲劳损伤谱的非平稳振动载荷的等损伤载荷谱编制方法,即利用时域法求解非平稳振动载荷疲劳损伤谱,再反解出与其具有等损伤能力的振动载荷谱;然后,通过轮缘润滑设备线路实测振动加速度与动应力,验证振动载荷谱编制方法有效性;最后,基于轨道车辆一个维护周期内转向架振动加速度线路跟踪数据,编制设备振动载荷谱。研究结果表明,基于提出方法编制的转向架设备振动载荷谱,可以有效地表征振动载荷能量频域分布特性且包含高振动能量,与非平稳振动载荷具有等损伤能力;同时,相比于常用方法编制的振动载荷谱,评估设备的疲劳损伤与设备实测应力评估的疲劳损伤也更为接近。

The vibration load of equipment mounted on the bogie of railway vehicles is complex and changeable.Compiling an appropriate vibration load spectrum is significant to structural reliability design.At present,the vibration load spectrum(Power spectral density)of equipment is generally compiled with the vibration energy value of the measured load or the measured stationary Gaussian vibration load obtained with the specific operating conditions,but the compiled load spectrum does not have the equivalent damage potential as the non-stationary vibration load of equipment experienced in service.Therefore,a method for compiling the equivalent damage load spectrum for a non-stationary vibration load is proposed based on the fatigue damage spectrum,that is,the time domain method is used to calculate the fatigue damage spectrum of non-stationary vibration load,and the equivalent damage load spectrum is compilated.Then,the compilated method is verified by the measured vibration load and dynamic strain of the wheel flange lubrication equipment mounted on the bogie.Finally,the vibration load spectrum of equipment mounted on the bogie is compilated by the measured vibration load in a maintenance cycle.The research results show that the compiled vibration load spectrum can validly represent distribution characteristics of vibration load energy in the frequency domain and contain more high vibration energy,which has the equivalent damage potential as non-stationary vibration load.Compared with the average spectrum and the standard spectrum,the fatigue damage evaluated by the compilated vibration spectrum is closer to the fatigue damage evaluated by measured stress.