动车组转臂节点刚度特性及疲劳寿命研究

Research on stiffness and fatigue life of axle box rubber joint for EMU

为探究动车组转臂节点刚度特性变化及其对疲劳寿命的影响,针对CRH3型动车组转臂节点,开展服役120万km后的转臂节点刚度测试,通过假设检验得到转臂节点刚度分布特征.基于单、双轴试验数据拟合橡胶Ogden本构模型,利用有限元软件建立转臂节点有限元模型,分析转臂节点结构应力、应变、位移及刚度变化规律.根据橡胶超弹性特性,利用主应力法结合S-N曲线得到了转臂节点在循环载荷下的疲劳寿命.研究结果表明:服役120万km的转臂节点径向刚度服从N(105.12,7.42)正态分布,轴向刚度服从N(12.95,1.75)正态分布.径向刚度和轴向刚度随载荷增加呈波动下降趋势,刚度变化均具有明显非线性特征.随着载荷的增大,转臂节点疲劳损伤区域逐渐扩大,疲劳寿命逐渐降低,疲劳寿命最小约为114万次,该结果可以为转臂节点设计、优化提供参考依据.

To explore the changes in stiffness characteristics of the axle box rubber joint and its influence on fatigue life for CRH3 high-speed EMU,the rubber joint stiffness is tested after 1.2 million kilometers of service mileage,and the distribution characteristics of stiffness are obtained through the hypothesis test.The Ogden constitutive of rubber is fitted to establish an accurate finite element model for rubber joint based on the uniaxial and biaxial test data.On this basis,the stress,strain,displacement,and the changing law of the stiffness are analyzed.The fatigue life for the joint under cyclic load is obtained by using the principal stress method and the S-N curve according to the hyper-elastic properties of rubber.The results show that the radial stiffness and the axial stiffness obey normal distribution N(105.12,7.42),N(12.95,1.752),respectively,for the rubber joint in service of 1.2 million kilometers.The radial stiffness and axial stiffness fluctuate and decrease with the increase of load,and the stiffness changes have obvious nonlinear characteristics.As the load increases,the fatigue damage area gradually expands,and the fatigue life gradually decreases.The minimum fatigue life is about 1.14 million times.The research provides a reference basis for the design and optimization of rubber joint.