Development of a Finite Element Methodology for Flexible Track Models in Railway Dynamics Applications

The dynamic analysis of railway vehicles involves the construction of three independent models: the vehicle model; the track model; and the wheel-rail contact model. In this work, a multibody formulation with Cartesian coordinates is used to describe the kinematic structure of the rigid bodies and joints that constitute the vehicle model. A methodology is also proposed in order to create detailed three-dimensional track models, which includes the flexibility of the rails and of the substructure. Here, the finite element methodology is used to model the rails as beams supported in a discrete manner by spring-damper systems that represent the flexibility of the pads, sleepers, ballast and substructure. The inclusion of flexible track models is very important to study the dynamic behavior of railway vehicles in realistic operation scenarios, especially when studying the impact of train operations on the infrastructure and, conversely, the damages on vehicles provoked by the track conditions. This topic has a significant economic impact on the vehicles maintenance and also affects the life cycle costs of tracks. The wheel-rail contact formulation used here allows obtaining, online during the dynamic analysis, the contact points location, even for the most general three-dimensional motion of the wheelsets with respect to the track. The methodology proposed to build flexible track models is validated here by comparing the results obtained with this new approach with the ones obtained with ANSYS. Furthermore, the methodology is demonstrated by studying the dynamic behavior of the Alfa Pendular railway vehicle.