Influence of Rail Decarburization Layer on Wheel-rail Transient Rolling Contact Behavior

Junyu KOU
2018 Journal of Mechanical Engineering  
Abstract:A 3D wheel-rail transient rolling contact model has been developed in consideration of rail decarburization layers using the explicit finite element method. The actual 3D geometry of wheel and rail, material nonlinearity and high-frequency dynamic interactions between vehicle and track are all taken into account. A penalty method based surface-to-surface contact algorithm is implemented to solve the transient wheel-rail rolling contact in the time domain, with which the normal and
more » ... nt contact solutions are obtained for any instants. Through comparison it is found that the existence of decarburization layer would increase the plastic deformation, resulting in larger contact patch and adhesion area, smaller normal and tangential contact stresses and lower frictional work. Due to the limited depth of the decarburization layer, being typically less than 1 mm, its influence on the shape and size of the contact patch is negligible, while those on contact stresses, adhension-slip distinction and frictional work are noticeable. A thicker decarburization layer could increase the plastic deformation of top layers of elements, while the plastic deformation of the first layer of element is lowered because of the redistribution of plastic deformation among the top layers. For longitudinally intermittent decarburization layers, the wheel-rail contact force and contact stresses all show noticeable variations at the boundaries between the decarburized and parent sections. Taking the running from a decarburized section to a parent one as an example, in which parameters of decarburization layer measured from an actual rail are used, the excited dynamic wheel-rail forces are 0.32 and 1.14 kN in the vertical and longitudinal directions, respectively, and the normal and tangential contact stresses and the frictional work are 4.42%, 19.71% and 83.19% larger than their stable values on the decarburized section. Such variations at boundary may cause uneven wear leading to geometry irregularities on the original smooth surface under certain conditions. Key words:rail decarburization layer;transient rolling contact;explicit finite element method;adhesion-slip distinction;plastic deformation * 国家自然科学基金(51675444,51605395)和牵引动力国家重点实验室自 主课题(2015TPL_T09)资助项目。20170502 收到初稿,20171228 收到修 改稿
doi:10.3901/jme.2018.04.101 fatcat:uvk6iwzcfbgy7pkajgbgiaqdfu