Modeling Wheel-Rail Contact With Pre-Calculated Lookup Tables in Arbitrary-Geometry Tracks With Irregularities

This paper shows a numerical method for the dynamic simulation of the wheel-rail contact interaction based on pre-calculated lookup tables for its use in railroad multibody dynamics. The multibody railroad model is developed for model-based condition monitoring of railway vehicles that make use of on-board real-time simulation. This application requires a numerically efficient and highly accurate computational model. The new capabilities of the contact model is its ability to be used in the modeling of tracks with arbitrary geometry that may include cross-level, longitudinal level, alignment and gauge variation irregularities using just 2 entries to the lookup table. This fact allows keeping to a minimum the computer memory needed to store the lookup table data. The lookup tables are created assuming constraint (rigid) contact between the wheel and the rail that reduces to 4 the number of degrees of freedom of the wheel. For that reason the wheel-rail normal contact forces are obtained as reaction forces in the multibody dynamic equations. This paper presents the wheelset kinematic description and wheel and rail profiles geometric analysis needed to calculate the contact constraints, the jacobian matrix and the time derivative of the jacobian matrix based on the lookup tables.