扣件参数对轮轨滑动接触热弹塑性的影响分析

Effects of fastening system parameters on rail thermo-elasto-plasticity in wheel-rail sliding contacts

利用有限元软件ANSYS建立热机直接耦合作用下的轮轨滑动接触热弹塑性有限元模型。采用与温度相关的变摩擦因数和材料参数,运用热机直接耦合法,考虑轮轨间非稳态热传导及轮轨与环境间热对流和热辐射的影响,考虑扣件系统对轮轨接触的影响,分析了不同扣件垂向刚度和扣件间距对钢轨受力和变形的影响。结果表明：轮轨接触斑附近钢轨的最大等效应力和弹性应变出现在钢轨接触表面上;在车轮滑过区域,钢轨最大等效应力和弹性应变发生在钢轨次表面上;钢轨的等效应力、最大变形和车轮垂向加速度在扣件垂向刚度为50 k N/mm时最小;从钢轨的应力、应变、变形和温升方面考虑,扣件间距在0.6~0.725 m间取值均较合理,车轮垂向加速度在扣件间距为0.6 m时最小。

A thermo-mechanical coupling elastic-plastic finite element model of Wheel-rail sliding Contact was established using finite element software ANSYS. The temperature-dependent friction coefficient and material properties were taken into consideration. A thermo-mechanical coupling calculation method was used. The non-steady heat conduction between wheel and rail, the heat convection and thermal radiation between wheel-rail and ambient were considered. The influence of fastener stiffness and fastener spacing on the stress and deformation of rail was analyzed when considering the fastener system. The results showed as followed： The maximum equivalent stress and elastic strain of the rail near contact patch occurred on the contact surface. The maximum equivalent stress and elastic strain of the rail occurred on the surface layer in the slide region. When the fastener stiffness was 50 k N / mm, the von Mises stress and deformation of rail and the vertical acceleration of wheel was minimum. The fastener spacing was more reasonable between 0.6 m to 0.725 m when considering stress, deformation and temperature of rail. The vertical acceleration of wheel reached the minimum when the fastener spacing was 0.6 m.