A dynamic stiffness and damping model for rail car center plate polymer liners

The center plate interface is made up of the body plate attached to the car body bolster, the polymer liner, and the bolster bowl, which is a part of the truck bolster. Roll motion of the rail car leads to the car body bolster rolling over the polymer liner on the truck bolster, which may result in partial loss of contact of the body plate with the polymer liner. This nonlinear phenomenon has a deleterious impact on the rail car dynamics. A technique for creating a center plate dynamic model accounting for the polymer liner and the loss of contact condition is presented here. Material tests were performed to model the stress-relaxation of the liner. A stiffness/damping model of the center plate accounting for the nonlinear effects of the lift-off was developed based on a nonlinear Winkler foundation model and was tested for a one-degree-of-freedom dynamic model. This continuous model was adapted into a 16 stiffness-damping element model to enable its usage in a NUCARS/spl trade/rail-car dynamic model.