The wheel-rail system is subjected to a complex interaction of several damage phenomena, even in competition with each other. In clean and dry environment, the most frequent phenomena are ratcheting and wear, especially in sliding condition such as in curve or braking, which result in the formation of surface cracks. In presence of fluid contaminant, such as rain or snow, rolling contact fatigue often prevails, because the surface cracks are filled by the fluid, which is pressurized at every load pass and promotes their propagation. Solid contaminants, such as sand, induce severe abrasive wear, leading to excessive modification of the wheel-rail contact patch and low duration. Thermal loads, occurring in shoe braking operation or in excessive sliding, can lead to heating cycles which alterate the material microstructure up to the formation of white etching layers (WEL). The experimental and computational experience of the University of Brescia in the study of these phenomena is presented.
Angelo Mazzù
Abstract
The wheel-rail system is subjected to a complex interaction of several damage phenomena, even in competition with each other. In clean and dry environment, the most frequent phenomena are ratcheting and wear, especially in sliding condition such as in curve or braking, which result in the formation of surface cracks. In presence of fluid contaminant, such as rain or snow, rolling contact fatigue often prevails, because the surface cracks are filled by the fluid, which is pressurized at every load pass and promotes their propagation. Solid contaminants, such as sand, induce severe abrasive wear, leading to excessive modification of the wheel-rail contact patch and low duration. Thermal loads, occurring in shoe braking operation or in excessive sliding, can lead to heating cycles which alterate the material microstructure up to the formation of white etching layers (WEL). The experimental and computational experience of the University of Brescia in the study of these phenomena is presented.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.