钢轨循环滚动接触过程残余应力-应变的变化规律研究

Study on Variation Rules of Rail Residual Stress and Strain During Cyclic Rail Rolling Contact

钢轨残余应力包括钢轨生产残余应力和轮轨循环滚动接触所产生的残余应力,两种残余应力共同决定了在役钢轨的损伤形式。提出了一种引入钢轨生产残余应力的有限元方法,采用Chaboche循环塑性本构模型,在接触表面施加循环移动的Kalker三维非赫兹接触法向、切向力和横向分布力模拟车轮运动,建立了曲线通过钢轨循环滚动接触有限元模型,并对钢轨循环滚动接触过程中残余应力-应变的变化规律进行研究。结果表明:随循环滚动次数的增加,钢轨生产残余应力很快重新分布并逐渐趋于稳定,而残余切应变则呈现近似线性增加;钢轨纵向残余应力和残余等效塑性应变随曲线半径的增加在数值上均逐渐减小、随摩擦系数的增加而逐渐增大、随纵向蠕滑率的增加而先增大后减小。

The residual stress of rail includes the rail production residual stress and the wheel rail cyclic rolling contact residual stress. The two kinds of residual stress jointly determine the damage form of the in service rail. A finite element method of introducing the rail production residual stress was presented. Based on this method and using the Chaboche cyclic plastic constitutive model, a finite element model of rail rolling contact for curve negotiation was established by applying cyclic normal tangential and horizontal force on the rail tread which was calculated byKaller^s three dimensional non Herz contact theory. The variation rules of residual stress and strain of rail during cyclic rolling contact were analyzed. The results show that with the increase of the number of rolling cycles, the rail production residual stress is redistributed quickly and gradually tends to be stable, while the residual shear strain shows an approximately linear increase. The longitudinal residual stress and the residual equivalent plastic strain of rail decrease in terms of numerical value with the increase of curvature radi us, and increase gradually with the increase of friction coefficient, and initially increase and then decrease with the increase of longitudinal creep rate.