Correlating human and flexible dummy head-neck injury performance

The Center for Injury Research (CfIR) has developed methods to derive and correlate rollover dummy head-neck injury with National Automotive Sampling System/Crash Injury Research (NASS/CIREN) data. In this paper, these methods are applied to other accident modes. Specifically, the authors investigated the application of the dummy rollover head-neck modifications, as well as structural injury risk, IARV, momentum exchange injury measures and criteria to frontal, offset and small overlap frontal and side impact testing. Recently, the National Highway Traffic Safety Administration (NHTSA) has implemented a comprehensive series of component regulations (FMVSS 126, FMVSS 216, FMVSS 226) which, in combination, are intended to drastically reduce the number of crashes and occupant injury and fatalities in rollovers and other modes. However, the stiffness of the dummy neck and the disparity between Injury Assessment Reference Value (IARV) and momentum exchange injury measures were not addressed. The authors opine that injury and fatality rates are high because of poor dummy-to-human stiffness and substantially underestimated IARV injury criteria compared to consensus momentum exchange injury measures. IIHS 40% offset and small overlap frontal and side impact tests were studied to observe the trajectory of the Hybrid III dummy head with production neck and evaluate injury measures. Then, the effect of substituting the production neck with the more flexible rollover neck was investigated. Estimates were made of the dummy head excursion, proximity of the head to vehicle structures at maximum excursion, the likelihood and severity of vehicle structure contact, and injury measures. Results indicate that, while the flexible neck in a rollover increases head excursion by 3 inches when contacted at 7 mph, the frontal and side impact tests described here result in head contact with vehicle structures and exceed the rollover-developed Abbreviated Injury Scale (AIS) ≥3 momentum exchange injury criteria of the integrated bending moment (IBM) and single and double integration product of head resultant acceleration (HRA).