轮对结构柔性对车轮辐板疲劳寿命的影响

针对高速动车非轴对称车轮辐板区域随机疲劳寿命问题,分别将轮对视为刚性体和柔性体建立了车辆-轨道系统动力学模型,仿真得到载荷时间历程和轮轨接触点在踏面上的位置时间历程。在三维有限元模型中使用约束方程模拟轮轴过盈配合,使非线性问题线性化,采用准静态叠加法得到应力时间历程。基于临界距离法中的点法,以疲劳破坏临界平面上的正应力为主循环计数参数,剪应力为辅助计数参数进行多轴循环计数,结合Spagnoli法和Miner理论研究了轮对结构柔性和车轴刚度对车轮辐板随机疲劳寿命的影响。研究结果表明,轮对结构柔性对车轮辐板疲劳寿命有较大影响。随着车轴刚度的降低,轮轨接触横向力的幅值显著增大,轮对模态的特征频率和车轮辐板区域的寿命降低。因此,在轮对轻量化设计时,需综合考虑车轴的结构刚度。

Influence of wheelset structural flexibility on the fatigue life of wheel web

For the random fatigue life problems of the high-speed EMU non-axisymmetrical wheel web,the wheelset considered as rigid body and flexible body respectively,two kinds of vehicle-track system dynamics models were established.The wheel-rail contact position time history on the tread and the load time history were obtained.The constraint equations were applied to simulate the interference fit in the 3D finite element model,thus make the nonlinear problem linearized.The stress time histories were acquired by quasi-static superposition method.The theory of critical distance was applied.The normal stress on the critical plane was treated as the main cycle count parameter,and the shear stress was treated as the auxiliary cycle count parameter in the multi-axial cycle counting process.On the basis of the Spagnoli law and the Miner theory,analysed the influence of wheelset structural flexibility and axle stiffness on the wheel web random fatigue life.The results show as follows:the wheelset structural flexi-bility has a great impact on the wheel web fatigue life;the lateral wheel-rail contact force amplitude increases significantly,the wheelset eigen-frequencies decreases,and the wheel web fatigue life decreases with the decreasing of the axle stiffness.As a result,the stiffness of the axle must be taken into conside-ration during the lightweight design of the wheelsets.