Coupled finite element and multibody system dynamics modeling of a three-dimensional railroad system

During the last two centuries, railroad vehicles have been an important means of transportation of both people and cargo, due to their economic and comfort advantages. Railroad vehicles are a highly economical means of transporting large quantities of cargo over long distances, and also provide a safe and comfortable means of passenger transport. Over the last 30 years or so, the finite element method (FEM) has become more widely used to model railroad systems including the rails, sleepers and substructure. Multibody system dynamics (MBS) software programs are used to model the contact between the wheels and the rails in an effort to study the contact forces and the general dynamics of railroad vehicles. Coupling both the FEM and MBS is a very useful technique to build a reliable model that includes the advantages of both methods. In this work, a full three-dimensional finite element model is created that uses beam, solid and spring elements to model the rails, fasteners, sleepers and substructure. The model treats the rails and the substructure as deformable bodies. Mode shapes of the finite element model are extracted for use in a MBS code to analyze the deformation of the track and substructure under dynamic loading conditions. The results of this new model agree well with results published in the literature.