Occupant Kinematics and Injury Response in Steer Maneuver-Induced Furrow Tripped Rollover Testing 2015-01-1478

Occupant kinematics during rollover motor vehicle collisions have been investigated over the past thirty years utilizing Anthropomorphic Test Devices (ATDs) in various test methodologies such as dolly rollover tests, CRIS testing, spin-fixture testing, and ramp-induced rollovers. Recent testing has utilized steer maneuver-induced furrow tripped rollovers to gain further understanding of vehicle kinematics, including the vehicle's pre-trip motion.

The current study consisted of two rollover tests utilizing instrumented test vehicles and instrumented ATDs to investigate occupant kinematics and injury response throughout the entire rollover sequences, from pre-trip vehicle motion to the position of rest. The two steer maneuver-induced furrow tripped rollover tests utilized a mid-sized 4-door sedan and a full-sized crew-cab pickup truck. The pickup truck was equipped with seatbelt pretensioners and rollover-activated side curtain airbags (RSCAs). The RSCAs were a prototype next generation design. The sedan was not equipped with these technologies. Each test vehicle contained two restrained instrumented 50^th-percentile male ATDs in the front outboard seating positions. The vehicles were accelerated using a tow system, released, and then maneuvered onto a dirt test surface by an automated steering controller resulting in a passenger-side-leading soil-tripped rollover. The RSCAs and seatbelt pretensioners in the pickup truck deployed prior to the first vehicle-to-ground contact. Occupant kinematics and ATD injury metrics were evaluated for the duration of the roll events.

The results of the study demonstrated two neck-loading events wherein the compressive loads in the upper neck and the Nij were well in excess of the Injury Assessment Reference Values (IARV). Both of these neck-loading events involved the driver ATD in the sedan. The vertical deformation of the driver side roof structure at the time of the first neck-loading event that exceeded the IARV was 4.4 cm (1.7 inches). The second of these events involved direct head-to-ground contact. Compressive neck loading events were preceded by a pattern of a peak in the filtered axial head acceleration, followed by a peak in the filtered axial chest acceleration A statistically significant positive correlation was observed between axial chest acceleration and axial compressive neck force. The interaction of the RSCAs with the two ATDs in the pickup truck was also investigated. The ATD loading and airbag interaction differed between the leading-side and trailing-side of the pickup truck. Occupant ejection was not observed to occur in this test.

Both tests showed multiple incidences when the occupants' heads were in proximity to the roof. The current study provides insight into occupant kinematics and injury potential during steer maneuver-induced furrow tripped rollover events, including the effects of RSCAs and seatbelt pretensioners.