Recovery Process of Wheel/rail Adhesion under the Action of Water-based Friction Modifier

Friction modifier (FM) has broad application prospects in the field of the control of wheel/rail interface adhesion behavior, however, the studies on the recovery process are rarely carried out. The wheel-rail adhesion recovery test under the conditions of water, glycerol and FM is carried out on the MJP-30A wheel-rail rolling-sliding wear and contact fatigue test machine. The recovery curves of the adhesion coefficient as the function of the number of cycles under different quantities of liquid are obtained. The recovery time and lubrication state are studied under three liquid conditions. The results show that the wheel-rail adhesion curves of recovery process under different liquid conditions are quite different. Compared with the dry condition, the water, glycerin solution and FM conditions could result in a significant decrease in the adhesion coefficient. Under the conditions of water and glycerin solution, the adhesion coefficient was declined twice, and then gradually increased to a stable level. The recovery time gradually increased subsequently to a stable level with the increase in the quantity of FM. With the excess of FM, the lubrication state of the recovery process experienced the elastohydrodynamic lubrication, mixed lubrication, boundary lubrication, and the dry condition at last. When the addition amount was 200 mu L, the initial adhesion coefficient was reduced to less than 0.1 and the limit of FM addition was 200 mu L. With the increase in cycle revolutions, the rheological index of FM gradually and the pressure carried by FM gradually were decreased, and the pressure carried by asperity was gradually increased. The load carried by asperity was increased from 1% to 46% with the rheological index decreasing from 1 to 0.75. The research reveals the wheel/rail adhesion recovery mechanism under the action of water-based FM, which provides and accumulates reference basis for its practical field application.