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The capabilities of a sophisticated tire force and moment model are investigated under extremes in operating conditions. The “Magic Formula” is the example tire model used in this study. Parameter values and characteristic curves are determined by optimization for a passenger-car tire which was tested under high load and slip conditions. These values are then compared to estimated parameter values which would have been extrapolated for the high-load range had only less-extreme data been available. Longitudinal and lateral forces under simple-slip and steady-state conditions are studied. Calculations are performed using proven optimization software adapted for this particular purpose. Also investigated using the Magic Formula is lateral force arising from pure camber. The Magic Formula is able to model the tire characteristics well even at extremes in vertical load and slip.

Presented herein are the results of analyses of single-vehicle-accident tripped-rollover maneuvers involving eight light vehicles from four classes of ground vehicles. In particular, the minimum rollover velocities of vehicles encountering soil and curb terrain discontinuities in non-tracking situations are correlated with various vehicle-design parameters. All of the vehicles, except for the passenger cars, are analyzed in both unladen and laden states. The minimum rollover velocities for the vehicles in the various maneuvers and states of lading are generated with a 14 degree-of-freedom computer model which was validated using experimental tripped-rollover maneuver results.

Computer simulations are frequently used to investigate vehicle motion in various maneuvers. Although a wide range of maneuvers and types of vehicle motion can presently be simulated by computer, most current vehicle dynamics simulations do not model vehicle behavior once a roadway or roadside barrier is encountered by a vehicle or once vehicle rollover occurs. If the forces generated through such vehicle body and terrain interactions can be accurately modelled, then computer simulation capabilities can be extended to include post-barrier-impact and post-rollover vehicle motion. This paper describes the development of a vehicle-terrain impact model. The terrain is modelled to represent a roadway, either level or sloped, as well as roadside hazards such as curbs, ditches, and guard rails.

A reliable dynamic measure to predict vehicle rollover under various conditions must be developed in order to quantitatively analyze the rollover propensities of vehicles. Several efforts have been made and are introduced in this paper on the development of such a dynamic measure of vehicle rollover stability. The position of the axis about which a vehicle rolls over (rollover axis) must be determined prior to developing a vehicle rollover propensity measure. For this reason, an investigation into the central axis concept was first performed. However, as shown in the paper, the unpredictability of the central axis position of the vehicle leads to the analyses of three other possible rollover axes. Investigations into the kinetic and potential energies of the vehicle system and its components have resulted in the modification and the extension of a previously developed energy based function called Rollover Prevention Energy Reserve (RPER).