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

Abstract

The fatigue phenomenon has been historically related to the railway industry. Nowadays, thanks to the high quality of the materials used, most of the recorded problems have been overcome although there are still degradation processes which are associated to fatigue and need to be considered for the definition of the maintenance campaigns and the general progress of the sector. In this paper, the latest improvements in the isotropic damage based high-cycle fatigue constitutive law proposed by Oller et al. (2005) are presented and the approach is used for the study of two regions of the railway path where fatigue mechanisms are experimentally detected: a straight section and a crossing element. The analysis of the affected areas is performed through a finite element simulation identifying the critical regions liable to the fatigue degradation when the structure interacts with high speed vehicles and predicting the initiation of the degradation at the rail head while capturing the physics of the problem. The potential of the methodology is shown through the case studies and the current shortcomings and the future lines of research are clearly stated.