Analysis of a Dolly Rollover with PC-Crash 2009-01-0822

This paper evaluates the use of PC-Crash simulation software for modeling the dynamics of a dolly rollover crash test. The specific test used for this research utilized a Ford sport utility vehicle and was run in accordance with SAE J2114. Scratches, gouges, tire marks and paint deposited on the test surface by the test vehicle were documented photographically and by digital survey and a diagram containing the layout of these items was created. The authors reviewed the test video to determine which part of the vehicle deposited each of these pieces of evidence. Position and orientation data for the vehicle in the test were then obtained using video analysis techniques. This data was then analyzed to determine the vehicle’s translational and rotational velocities throughout the test.

Next, the test was modeled using PC-Crash. The simulation was optimized to yield a reasonable fit with the actual test dynamics by changing the following parameters in PC-Crash: (1) the friction coefficient associated with each vehicle-to-ground impact; (2) the coefficient of restitution for vehicle-to-ground impacts; (3) the vehicle body stiffness; and (4) the vehicle suspension and damping. PC-Crash results were then compared to the actual dynamics data to determine how well the simulation matched the actual translational, vertical and roll velocities throughout the test. Comparisons were also carried out in terms of the vehicle’s kinetic energy and the forces applied to the vehicle during each vehicle-to-ground impact. The input parameters to the final simulation are discussed, as are issues that came up in the modeling process. The current capabilities of PC-Crash for rollover modeling are discussed and suggestions are made for how PC-Crash might be improved for modeling rollovers.