高速列车转向架应力谱分组方法研究

RESEARCH ON STRESS SPECTRUM GROUPING METHOD OF HIGH SPEED EMU BOGIE

应力谱对结构疲劳强度评估和可靠性设计有着重要意义,为了准确评估结构的疲劳强度,通过某型高速动车组实际运营线路上的动应力测试试验,获取动力转向架构架疲劳关键部位的应力-时间历程,采用等距分组方法编制应力谱,结合Palmgren-Miner线性累积损伤理论,计算了不同分组数下应力谱的每公里疲劳损伤值,分析了不同分组数对疲劳损伤的影响规律。结果表明,分组数过少会引起疲劳损伤值的偏差,随着分组数的增加,计算的损伤值逐渐减小,并趋于定值,这是由动车组构架动应力小应力循环高度集中的特点引起的。同时提出了一种适用于构架结构应力谱的不等距分组方法,研究结果可为构架结构的设计提供依据。

The determination of structural dynamic stress spectrum is of great significance in the structural fatigue strength evaluation as well as reliability design.To evaluate structure of fatigue strength accurately,stress history on fatigue key parts of motor bogie framework was obtained through dynamic stress test of high-speed EMU on actual operation line.Fatigue damage values per kilometer of stress spectra with different grouping numbers were calculated using equidistant grouping method and Palmgren-Miner linear cumulative damage theory.Then,the effect of different group number on fatigue damage was analyzed.The results show that when the grouping number is small,it can lead to deviation of fatigue damage.As the grouping number increasing,damage decreasing,and tends to the theoretical value.This phenomenon can be interpreted by the EMU framework dynamic stress characteristic of small stress cycles high concentration.Meanwhile,an unequal distance grouping method was presented which is applicable to framework structure stress spectrum.The study can provide the basis for framework structure design.