Study On Friction And Wear Behavior Of Wheel/rail Materials Under Different Working Conditions

The wheel/rail contact is the most basic and complex problem in the operation of the railway system. In today’s world of railway transport network has there are several primary characteristics of railway-transportation network, which concluding increased amount of carriage,axle load on rail and rate, high density of transportation. Thus it comes to the results that contact surface of wheel/rail material wearing aggravated, the servicing life of wheel/rail material shorten, the impact of using tackifier on the wheel/rail materials and so on. Such problems have a profound influence on railway transportation system.The friction and wear experiments of wheel/rail materials were carried out using MMS-2A friction and wear tester under different working conditions. Furthermore, the effect of dry, water and sanding conditions on friction and wear behaviors of wheel/rail materials was explored in detail. The effect of axle load on friction and wear behaviors of wheel/rail materials was investigated and analyzed under the water condition. The contact stress and contact zone of wheel/rail specimens were calculated using finite element software ANSYS according to the simulation experimental parameters.Main conclusions are drawn as follows.1. The water medium obviously decrease rolling friction coefficient and wear volume of wheel/rail specimens. Sanding can increase rolling friction coefficient and wear volume of wheel/rail specimens under the water condition. Furthermore, sanding can aggravate the surface damage of wheel/rail specimens. Rolling friction coefficient can come to the normal level during the dry condition after sanding. With the conditions changing from water, dry and water sanding, the surface damage of wheel specimen transforms from slight delamination to serious spalling damage. The delamination damage is dominant for the rail specimen. However, the spalling damage of rail specimen is slighter than that of wheel specimen.2. With an increase of axle load, rolling friction coefficient and wear volume of wheel/rail materials decrease. With the increase from110N to170N, the surface damage of wheel specimen transforms from slight delamination to serious spalling damage. However, the spalling damage of rail specimen is slighter than that of wheel specimen.3. Finite element simulation results show that the friction coefficient of wheel/rail has no obvious effect on the maximal contact stress and the contact zone of the wheel/rail interface under the same loading condition. With an increase of axle load, the contact radius and area of wheel/rail contact zone increase under the same friction coefficient condition. The maximal contact stress of contact zone presents a nonlinear growth with an increase of axle load. Furthermore, the increase of contact stress becomes flat with an increase of axle load.