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Abstract
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OBJECTIVE: The goal of this study was to characterize the rollover crash and to evaluate the repeatability of the Dynamic Rollover Test System (DRoTS) in terms of initial roof-to-ground contact conditions, vehicle kinematics, road reaction forces and vehicle deformation.
METHODS: Four rollover crash tests were performed on two pairs of replicate vehicles (two sedan tests and two compact multi-purpose van (MPV) tests), instrumented with a custom inertial measurement unit to measure vehicle and global kinematics and string potentiometers to measure pillar deformation time histories. The road was instrumented with load cells to measure reaction loads and an optical encoder to measure road velocity. Laser scans of pre- and post-test vehicles were taken to provide detailed deformation maps.
RESULTS: Initial conditions were found to be repeatable, with the largest difference seen in drop height of 20mm while roll rate, roll angle, pitch angle, road velocity, drop velocity, mass, and moment of inertia were all 7% different or less. Vehicle kinematics (roll rate, road speed, roll and pitch angle, global Z' acceleration, and global Z' velocity) were similar throughout the impact, however differences were seen in the sedan tests because of a vehicle fixation problem and differences were seen in the MPV tests due to an increase in reaction forces during leading side impact likely caused by disparities in roll angle (3° difference) and mass properties (2.2% in MOI, 53.5mm difference in CG location).
CONCLUSIONS: Despite those issues, kinetic and deformation measures showed a high degree of repeatability which is necessary for assessing injury risk in rollover as roof strength positively correlates with injury risk (Brumbelow, 2009). Improvements of the test equipment and matching mass properties will ensure highly repeatable initial conditions, vehicle kinematics, kinetics, and deformations.
Language: en |