动车组构架垂向载荷统计特性研究

Research on Statistics Characteristic of Vertical Load for High-speed Train Bogie

构架载荷谱分析是对构架进行疲劳可靠性评估的基础,现以某一车型的跟踪实验为背景,运用测力弹簧方法记录动力转向架轴箱弹簧的垂向载荷时间历程。选取某一运行区间的载荷数据作为样本,并将样本按速度等级划分,再次选取若干天相同线路相同区段的数据对样本进行扩充。联合不等组距及随机平均滑动直方图法,利用雨流计数得出载荷谱。根据载荷谱用极大似然法估计随机载荷在对数正态分布下的参数。最后根据累积分布函数曲线从统计学的角度给出一个运行区间内载荷幅值分布的变化情况。研究结果表明,根据载荷谱特点重新调整组距并对直方图进行平均处理有助于快速获得满足卡方校验的参数估计值;在一个运行区间内,速度200km/h以下时,随着速度的提高载荷谱中大载荷出现的概率明显提升,此时这一规律与速度关系显著与加速,减速关系不显著。当速度超过200km/h时大载荷出现的概率仍然较高,但其统计特性会受到速度,区间,加速,减速多种条件的综合影响。

bogie load spectrum analysis is the foundation of fatigue reliability evaluation which is carried out on the bogie, this paper is set in a kind of vehicle＇s tracking experiment, using the transducer for axle spring to record the data during accelerating process and clas- sify it in different velocity. Then extend the sample by selecting another group of data from the same zone. Combine the method of a- daptive histogram and random average shifted histogram （RASH） to have a better load spectrum according to lognormal distribution. Calculate the distribution parameters using Maximum Likelihood Estimation （MLE）. The statistical results show that under the speed of 200km per hour, the probability of heavy load has a significant increase, and this regularity almost completely depend on velocity. In addition, it has little relation with speed up or slows down. When the speed is more than 200km per hour , the probability of heavy load still keep high level, but the statistic characteristics are influenced by multi-factor such as velocity, zone, speed up or slow down, etc.