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The use of computer simulation of vehicle dynamics as a development tool has come into its own over the past few decades. “Simulated” testing on a computer makes possible a degree of control and repeatability that allows the automotive engineer to determine the influence of design variables on different aspects of dynamic performance in ways that would be difficult or impossible by experimental methods. One of the software tools receiving wide acceptance for simulating trucks and combination vehicles is Truck-Sim™. The attraction of this program arises in part from its foundation of truck modeling methods developed at the University of Michigan Transportation Research Institute over the past two decades, and the use of an advanced graphical user interface to make the software both easy to understand and easy to use by design and development engineers.

The ability to accurately simulate vehicle dynamics behavior with a mathematical model is limited by the quality of the tire model. In fact, the tire is often the single most important component in determining correlation between a mathematical vehicle model and measured experimental results. Tire data for heavy trucks are more difficult and expensive to acquire than passenger car and light truck data, and, consequently, there has been little published experience testing or modeling these tires. This paper shows how the analysts can integrate heterogenous tire modeling methods into one coherent tire model suitable for the simulation of an over-the-road 18-wheel tractor-trailer configuration. The methods used in this paper are: Tire F&M modeling that represents the effect of tread wear, water depth, and speed, as well as combined longitudinal and lateral slip conditions.