Dynamic modeling and simulation of three-piece freight vehicle suspensions with nonlinear frictional behaviour using Adams/Rail

At present there are approximately 2.5 million three-piece bogies operating under North American freight vehicles. Although US bogie manufacturers offer a variety of designs to vehicle builders, central to all of these bogie designs are the nonlinear frictional characteristics inherent in the bogie suspension. These characteristics derive from the dynamic behaviour of the friction wedges. Friction wedges are small triangular metal elements that are held into position via spring loading, and function as the primary mechanism for vibrational energy dissipation between the bolster and side frame. Therefore, as a prerequisite to obtaining a realistic dynamic model of a typical three-piece bogie, an accurate model of the load-sensitive behaviour of these dry friction devices is required. Using design specifications from US bogie manufacturers and experimental data from the open literature, a load-dependent friction wedge model was developed using the ADAMS/View environment. After this model was validated against theoretical benchmarks, it was imported into an ADAMS/Rail vehicle model of a typical North American three piece bogie. The results of model development for both the friction wedge and three-piece bogie are presented, as well as ADAMS/Rail simulation results of the bogie dynamics under a variety of operating conditions.