Trajectory Model of Occupants Ejected in Rollover Crashes


Dr. James R. Funk, Mr. Peter A. Luepke


2007 SAE World Congress (SP-2063), Detroit, MI, April 16-19, 2007. Warrendale, PA. Society of Automotive Engineers. 2007; 9 pp. SAE # 2007-01-0742.


A simple two-dimensional particle model was developed to predict the airborne trajectory, landing point, tumbling distance, and rest position of an occupant ejected in a rollover crash. The ejected occupant was modeled as a projectile that was launched tangentially at a given radius from the center of gravity of the vehicle. The landing and tumbling phases of the ejection were modeled assuming a constant coefficient of friction between the occupant and the ground. Model parameters were optimized based on a dolly rollover test of a 1998 Ford Expedition in which five unbelted anthropomorphic test devices (ATDs) were completely ejected. A generalized vehicle dynamics model was also created assuming a constant translational deceleration and a prescribed roll rate function. Predictions using the generalized model were validated against the results of the full-scale rollover test to estimate the expected error when using the model in a real-world situation. The model was shown to be a useful tool for investigating possible ejection points and occupant trajectories in rollover crashes.

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