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This study examines through computer simulation the vehicle dynamics regime of vehicle entry into a travel lane via traversal of a vertical change in pavement elevation. A three-dimensional vehicle dynamics software package is used to model a vehicle as a six degree-of-freedom sprung mass with up to five degrees-of-freedom for each unsprung mass for each axle. The parameters of the simulator’s radial and sidewall tire force models are determined through correlation with full-scale vehicle traversal tests. The correlation parameters include vehicle speed, heading, yaw rate and lateral acceleration. The simulation is first calibrated by successfully modeling vehicle traversal of a pavement edge at shallow angles.

A commercially-available two-dimensional software program, validated to model high speed collisions, was extended to analyze rear-end collisions involving speed changes below 10 miles per hour. Simulation results were compared to the results of several series of published full-scale staged collisions. A total of 84 rear-end crash tests, involving 20 vehicles of different makes and models, were analyzed. Test conditions included free-rolling as well as braked vehicles, and in-line as well as oblique collision configurations. The analysis demonstrates that the simulation model provides accurate and reliable predictions of vehicle delta-V's for rear-end collisions, under aligned and oblique conditions, and with free-rolling and braked conditions for the foam core and piston-equipped bumper types examined.

This study examines through computer simulation the reconstruction of on-road vehicle rollover accidents induced by a driver steering maneuver. The three-dimensional vehicle dynamics software package SIMON is used to model a set of four test vehicles as six degree-of-freedom sprung masses with up to five degrees-of-freedom for each unsprung mass. The performance of the simulator's physics model, in the context of accident reconstruction, is evaluated through correlation with full-scale vehicle rollover tests. Of specific interest to this study was simulation of the trip phase of the vehicle's motion. The correlation parameters include vehicle trajectory, speed, heading angle, yaw rate, roll angle, roll rate and lateral acceleration. SIMON's capacity to accurately model the physics of a test vehicle's suspension and tire kinetics in the pre-trip and trip phases of motion is evaluated by modeling a set of four instrumented full-scale tests of steering-induced rollovers.