动车组车辆转臂节点疲劳寿命评估

Fatigue Life Evaluation of EMU Vehicle Articulation Joints

目的:动车组车辆在运行过程中,其转臂节点在机械振动和外部环境的影响下,容易产生机械损伤和疲劳失效,需要对动车组车辆转臂节点的疲劳寿命进行评估。方法:针对动车组转臂节点,开展3组载荷、共6个转臂节点的疲劳试验,获得了不同载荷条件下的转臂节点径向刚度变化率;以橡胶材料Ogden为本构模型,建立转臂节点疲劳寿命有限元模型,分析了载荷对转臂节点疲劳损伤和疲劳寿命的影响规律。结果及结论:疲劳试验结果表明:载荷增加到90 kN后,转臂节点径向刚度变化率快速增大;200万次疲劳试验后,转臂节点径向刚度变化率为25.3%,且达到失效限值,橡胶出现部分溶胶现象,但并未出现明显裂纹。仿真计算结果表明:转臂节点橡胶层疲劳损伤的最大位置位于受载侧两端;随着载荷幅值的增加,转臂节点疲劳损伤逐渐向端部扩散,最终汇聚至橡胶层两端内外表面,且转臂节点疲劳寿命逐步减小;载荷由27 kN增大至100 kN时,转臂节点疲劳寿命急剧下降,径向疲劳寿命由790万次降低至88万次,轴向疲劳寿命由948万次降低至133万次。仿真计算结果与试验结果的一致性较好,说明仿真模型准确且可靠。

Objective:During the operation of EMU vehicles,the articulation joints are susceptible to mechanical damage and fatigue failure under the influence of mechanical vibration and external environment.Therefore,it is necessary to assess the fatigue life of the articulation joints in EMU.Method:For the articulation joints of EMU,fatigue tests are conducted on three sets of loads,involving a total of six articulation joints.The radial stiffness variation rates of the articulation joints under different load conditions are obtained.Taking the rubber material Ogden as the constitutive model,a finite element model for the fatigue life of the articulation joints is established,and the load impact on the fatigue damage and fatigue life of the articulation joints is analyzed.Result&Conclusion:The results of the fatigue tests show that the radial stiffness variation rate of the articulation joints increases rapidly when the load is increased to 90 kN.After 2 million fatigue tests,the radial stiffness variation rate of the articulation joints is 25.3%,reaching the failure limit.The rubber material exhibits partial soling phenomenon,but no obvious cracks appeared.Simulation calculation results indicate that the maximum fatigue damage in the rubber layer of the articulation joints is located at both ends of the loaded side.With increasing load amplitude,the fatigue damage in the articulation joints gradually spreads towards the end,ultimately converging on the inner and outer surfaces of the rubber layer,and the fatigue life of the articulation joints gradually decreases.As the load increases from 27 kN to 100 kN,the fatigue life of the articulation joints sharply decreases from 7.9 million cycles to 880,000 cycles,and the axial fatigue life decreases from 9.48 million cycles to 1.33 million cycles.The consistency between the simulation results and the experimental results is good,indicating the accuracy and reliability of the simulation model.