考虑棘轮效应的高速轮轨粗糙表面法向接触刚度研究

摘要

轮轨接触表面状态直接影响轮轨接触刚度,而高速列车轮轨滚动接触过程中,轮轨表层材料产生弹塑性变形,且轮轨接触表面在循环接触载荷作用下,轮轨表层材料塑性变形累积产生棘轮效应,因此,研究高速轮轨法向接触刚度时要考虑棘轮效应.基于Weierstrass-Mandelbrot函数分形理论建立高速轮轨滚动接触粗糙度数值模型,考虑轮轨滚动接触棘轮效应,采用非线性有限元软件ABAQUS建立高速轮轨滚动接触微观有限元模型.数值计算结果表明:接触载荷作用下考虑轮轨弹塑性变形可更为准确分析高速轮轨法向接触刚度;循环接触载荷作用下,钢轨表层材料等效塑性应变随接触载荷循环次数增加先增加后趋于稳定,从而导致轮轨接触刚度也先下降然后趋于稳定;在相同接触载荷循环次数作用下,法向载荷对高速轮轨接触刚度影响明显,而摩擦因数对轮轨法向接触刚度影响较小.%The states of wheel/rail contact surfaces directly affect the wheel/rail contact stiffness,while the plastic deformation is produced in the wheel/rail surface materials during the rolling contact process of high-speed train,and the ratchet effect is produced caused by the accumulation of wheel-rail surface plastic deformation under cyclic contact load.Therefore,the ratchet effect should be considered when studying the normal contact stiffness of the high-speed wheel/rail.A roughness numerical model of high-speed wheel/rail rolling contact was established based on fractal theory of Weierstrass-Mandelbrot function,and wheel/rail rolling contact microscopic finite element model was constructed by nonlinear finite element software package ABAQUS based on normal contact stiffness theory and considering the ratchet effect of wheel/rail rolling contact.The numerical calculation results show that there may be more accurate analysis of normal contact stiffness by considering the role of plastic deformation of high-speed wheel/rail.Under cyclic contact load,the equivalent plastic strain of rail surface material is increased firstly then trends to be stable with the increase of contact load cycles,and the wheel/rail contact stiffness is decreased firstly then also trends to be stable.Under the same contact load cycles,normal load has obvious influence on wheel/rail contact stiffness,while friction coefficient has less influence on contact stiffness.