Research On Simulating Experiment Of The Oblique Crack Of Rail Tread

Wheel-rail surface damage is one of the most serious problems in railway engineering, of which the mechanism have not been perfectly explained. With the tendency of the railway transportation into heavy haul and high-speed, the problem of surface fatigue damage due to wheel-rail rolling contact becomes more and more serious. The reseaches on the initiation and extension of oblique cracks have the oretical guidance to release and control oblique crack damage in high speed railway domain.The oblique crack of rail surface, which belongs to fatigue damage, is one of the most significant phenomena reflecting the type of rail damage. After initiation of oblique cracks, they would prolong to the centre of the rail, which may jeopardize the safety of train operation because of transverse rupture of the rail. At present, the oblique crack of rail surface is the principal reason for renewal of GuangShen Quasi-high Speed Railway.Based on the study on surface damage of wheel-rail rolling contact at home and abroad, this paper analyzed the phenomenon of oblique crack on curved track of GuangShen Quasi-high Speed Railway. The experiments of simulating the surface damage have been carried on by using JD-1 rail-wheel tribology simulating machine. The damage phenomena were investigated by means of optical microscope and SEM analysis. The results of experiments demonstrated that contact stress of conical surface contact is larger than that of arc contact and that lateral creep is one of the most important factors for simulating oblique crack damage. The experiments also revealed that larger velocity led to less wear lose but more possibility to cause rail contact fatigue; braking force and axle load were proportional to wheel-rail contact stress; and the increase of them promoted the generation of oblique cracks.