Simulation research on temperature field and stress field during rail grinding

Abstract

The rail grinding process generates a large amount of heat, which could lead to heat damage on the ground rails. But, the whole temperature field of rail ground by the grinding train has not been explored in detail. In the present study, finite element models of a rail and grinding wheel were established to simulate the rail grinding process. The temperature field and the thermo-mechanical coupling stress during rail grinding, and the residual stress after grinding were studied. Furthermore, through simplifying grinding wheels into heat sources, the temperature field of rail ground by a whole grinding train was investigated as well. The results indicated that the grinding temperature and the residual stress increased with the grinding depth and rotational speed, but decreased with the feed speed and radius of rail head. The thermo-mechanical coupling stress increased with the radius of rail head and grinding depth, and decreased with the rotational speed and feed speed. When ground by the whole grinding train, the increase in the number of grinding wheels at the same grinding angle and adjacent angles could lead to a rise in temperature on the rail surface. The speeds of grinding train and the rail head radius also have an influence on the temperature. The optimal feed speed of the grinding train should be below 12 km/h for R300, 16 km/h for R80, and 18 km/h for R13. The results could be used to optimize the grinding parameters and grinding pattern in the field.

On the numerical study of fatigue process in rail heads by means of an isotropic damage based high-cycle fatigue constitutive law

“…The samples tested there were obtained from rail heads in unused conditions and thus the properties exhibited by the material are suitable for the study of the rail fatigue behaviour. Despite this, the effect that the maintenance operations introduce in the rail along its life [52,53] are not reflected in these original properties and have not been considered in the undergone study.…”