a b s t r a c tThe prediction of the wear at the wheel-rail interface is a fundamental problem in the railway field, mainly correlated to the planning of maintenance interventions, vehicle stability and the possibility of researching specific strategies for the wheel and rail profile optimization. In this work the Authors present a model specifically developed for the evaluation of the wheel and rail profile evolution due to wear, whose layout is made up of two mutually interactive but separate units: a vehicle model for the dynamic analysis and a model for the wear estimation. The first one is made up of two parts that interact online during the dynamic simulations: a 3D multibody model of the railway vehicle implemented in Simpack Rail (a commercial software for the analysis of multibody systems) and an innovative 3D global contact model (developed by the Authors in previous works) for the detection of the contact points between wheel and rail and for the calculation of the forces in the contact patches (implemented in C/C++environment). The wear model, implemented in the Matlab environment, is mainly based on experimental relationships found in literature between the removed material and the energy dissipated by friction at the contact. It starts from the outputs of the dynamic simulations (position of contact points, contact forces and global creepages) and calculates the pressures inside the contact patches through a local contact model (FASTSIM algorithm); then the material removed due to wear is evaluated and the worn profiles of wheel and rail are obtained. This approach allows the evaluation of both the quantity of removed material and its distribution along the wheel and rail profiles in order to analyze the development of the profiles shape during their lifetime.The whole model is based on a discrete process: each discrete step consists in one dynamic simulation and one profile update by means of the wear model while, within the discrete step, the profiles are supposed to be constant. The choice of an appropriate step is fundamental in terms of precision and computational load. Moreover the different time scales characterizing the wheel and rail wear evolution require the development of a suitable strategy for the profile update: the strategy proposed by the Authors is based both on the total distance traveled by the considered vehicle and on the total tonnage burden on the track. The entire model has been developed and validated in collaboration with Trenitalia S.p.A. and Rete Ferroviaria Italiana (RFI), which have provided the technical documentation and the experimental results relating to some tests performed with the vehicle DMU Aln 501 Minuetto on the Aosta-Pre Saint Didier line.

No abstract

No abstract

No abstract

a b s t r a c tIn railway applications, the estimation of wear at the wheel-rail interface is an important field of study, mainly correlated to the planning of maintenance interventions, vehicle stability and the possibility of carrying out specific strategies for the wheel profile optimization. In this work the authors present a model for the evaluation of wheel and rail profile evolution due to wear specifically developed for complex railway networks. The model layout is made up of two mutually interactive but separate units: a vehicle model (composed of the multibody model and the global contact model) for the dynamical analysis and a model for the wear evaluation (composed of the local contact model, the wear evaluation procedure and the profile update strategy).The authors propose a statistical approach for the railway track description to study complex railway lines in order to achieve general significant accuracy results in a reasonable time: in fact the exhaustive simulation of the vehicle dynamics and of wear evolution on all the railway network turn out to be too expensive in terms of computational effort for each practical purpose.The wear model has been validated in collaboration with Trenitalia S.P.A and RFI, which have provided the technical documentation and the experimental data relating to some tests performed on a scenario that exhibits serious problems in terms of wear: the vehicle ALn 501 "Minuetto" circulating on the Aosta-Pre Saint Didier Italian line.