Vertical dynamic behavior of three-piece bogie suspensions with two types of friction wedge

There are two common types of friction wedge in the suspension system of a three-piece bogie—the “constant damping” wedge and the variable damping wedge. A generic wagon–track dynamics interaction model has been developed to investigate the dynamic behaviour of suspension systems with these two wedge types .The model differs from usual approaches in two aspects: (1) the mass of the wedge is considered in the model and, (2) the track is modelled as a flexible element with multiple degrees of freedom modelling sleepers, ballast and subgrade. The dynamic response characteristics of the two suspension-wedge systems are simulated, compared and discussed for different wedge friction conditions and track input frequencies.