Dynamic simulation of railway vehicles: wheel/rail contact analysis

The multibody simulation of railway vehicle dynamics needs a reliable and efficient method to evaluate the contact points between wheel and rail, because their positions have a considerable influence on the direction and intensity of the contact forces. In this work, an innovative semi-analytic procedure for the detection of the wheel/rail contact points (named the DIFF method) is presented. This method considers the wheel and the rail as two surfaces whose analytic expressions are known and is based on the idea that in the contact points the difference between the surfaces has local minima and is equivalent to solving an algebraic two-dimensional system. The original problem can be reduced analytically to a simple scalar equation that can be easily solved numerically (since the problem dimension is one, even elementary non-iterative algorithms can be efficient).