A Study of Vehicle Impacts during Dolly Rollover Tests and Comparison to Frontal and Side Impact Tests 2014-01-0529

Studies of rollover accidents have reported crash attributes such as the number of rolls, rollout distance, initial over-the-ground speed, average roll rate, average over-the-ground deceleration, magnitude of roof deformation, cumulative damage, time and post-crash headroom. While these more general attributes are related to the repeated vehicle-to-ground impacts during a rollover, it has been previously shown [1] that a specific ground impact during a rollover and its consequences can be studied in more detail by using its acceleration time history (crash pulse or impulse) and energy loss. These two quantities are particularly meaningful to use when studying impact mechanics, however, they are limited to circumstances where the data exists, which means real-world on-road crashes cannot be used directly.

Acceleration and energy data have been collected and previously published for three Subaru Forester dolly rollover tests, and have been studied in more detail in this writing. This same vehicle model has also been crash tested by the NHTSA. Nine single event crash tests were performed by the NHTSA, providing the unique opportunity to analyze and compare the effects of selected parameters in all twelve tests on the same vehicle architecture.

This research study builds upon previous analyses of three instrumented SAE J2114 dolly rollover tests using 2003 model-year Subaru Forester vehicles, to study the acceleration crash pulses acting on the rolling vehicles during ground impacts. The accelerations and velocities at the vehicle centers-of-gravity in the dolly rollover tests are further characterized. The rollover impact data is then compared to planar single frontal and side impact collision tests using the same make/model of vehicle. The analysis shows how the acceleration crash pulse peaks, averages, durations, and energies quantitatively compare for the different crash types.