Citation

Peng Q, Chirwa EC, Yang J. Int. J. Crashworthiness 2011; 17(2): 195-207.

Copyright

(Copyright © 2011, Informa - Taylor and Francis Group)

DOI

10.1080/13588265.2011.637834

PMID

unavailable

Abstract

There is no doubt that rollovers are more complicated than planar crashes and attributed injury mechanisms are still debated among original equipment manufacturers (OEMs), design engineers, safety experts, impact biomechanics specialists and research scholars at academic institutions. Two intertwining factors and their assumed interpretations have been at the core of these discourses, namely the roof crush strength versus the legislative requirement Federal Motor Vehicle Safety Standard 216 (FMVSS 216) and the real associated injuries in rollovers. The newly updated roof crush standard FMVSS 216 (effective from 2012) seems to answer some of the queries raised in the many debates, which include the increase in the applied force from 1.5 to 3.0 times the vehicle's unloaded weight, the addition to the legislative requirement of heavier vehicles between 2.7 and 4.5 tons and the improved crush procedure that includes the roof testing of both sides at platen combination angles of 5° pitch and 25° roll. From the National Highway Traffic Safety Administration's (NHTSA) own regulatory analysis estimates, the new FMVSS 216 will save 135 lives from the recorded 10,000 yearly rollover fatalities. The interpretation of these survival figures is that the societal cost is still high and can be further reduced by looking at the European rollover analysis and how the European Union (EU) has approached the reconstruction of rollover problems. Through in-depth numerical analysis using finite element model of a passenger vehicle tested at different platen combination of pitch-to-roll angles, this paper demonstrates that using the regulatory requirement of 5° pitch and 25° roll does not constitute the worst loading condition. The roof resisting resultant force and the energy associated therewith depict the force for the 10° pitch and 45° roll angle combination to be, in reality, twice smaller than that for the 5° pitch and 25° roll angle combination. This can be interpreted with conviction that occupants will be put at high risk of injuries because the roof, despite meeting the new FMVSS 216 requirement, will collapse catastrophically. As a result, the new regulation will be rendered inadequate unless the platen angle combination of 10° pitch and 45° roll is adopted.