| Wheel rail relationship is one of the basic problems of rail transportation system. And wheel rail contact problem is very important issue which has always been very seriously by scholars at home and abroad,and have never been stopped studying Along with the speed of passenger trains increased and the development of heavy trucks, Has long been plagued by the railway wheel rail stripping, abrasion and other damage on the surface of the wheel and rail fatigue has been increasingly serious. In order to find out the reason and puts forward measures to improve further,must carefully study analysis was carried out on the wheel rail contact stress and so on.It make sense of the high-speed train safe operation, reduce the transportation cost and development. The dissertation mainly puts the method of finite element method in action,combines with the contact spot measured by prescale films to prove the validity of the calculation model and method,studys influence factors on characteristics of wheel/rail contact, with work as follows.First of all, introduce the research background and significance of this dissertation, summarize the wheel/rail contact theory and the present status of experimental studies, make a clear of thesis research purpose and methods.And then the simulation object on the tread profile of the wheel is measured to obtain the tread coordinate data,.Spline curve fitting method is applied to obtain the contour line of the wheel type and surface, and application of three-dimensional modeling software and Hypermesh are sued to get fine grid of wheel/rail contact parts to ensure the consistency of finite element model and simulation object.Measuring the size of wheel/rail contact spot on the scene by pressure sensitive films,compared with the size of the contact spot the finite element simulation rounds of gravity (no load), shows the validity of the finite element method and contact preferences. On the basis of the research the continual chang of the wheel/rail contact influence parameters(such as the axle load,the wheel transverse, shaking head angle and longitudinal RuHuaLi) and the relative stability of wheel/rail contact influence parameters (such as measured different running mileage in the wheel profile, the wheel diameter, the material properties of wheel and rail, the rail base slope) are studyed to obtain the change rule of wheel/rail contact spot and the contact stress.The results show that the wheel/rail contact pressure as well as the internal Mises stress, shear stress will increase with the increase of the axle load and the decrease of wheel diameter and the rail base slope (1:20～1:40);The wheelset transverse and yaw angle movement changes has a great influence on the matching of the wheel/rail geometry model and surface.The worst condition is that the rim is prone to contact with the rail with the shook head and transverse movement;Contact stress reduces with the matching on the increase of abrasion wheel/rail type and surface,but to a certain extent, the contact stress is rising fast and the wheel profiling is carried out in time; Longitudinal tangent force of Wheel/rail make the position of the maximum wheel/rail contact stress move towards the contact surface,which has an important influence on the wheel/rail surface damage; The increase of wheel/rail material yield strength will make the contact stress increases, however, improve the current situation of the wheel/rail plastic deformation.Wheel rail contact factors were studied using finite element method in this paper, is of great significance to improve the wheel rail contact mechanics research,the engineering practice and the design. |
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