Biomechanical impact response of the human chin and manubrium.

Chin-to-chest impact commonly occurs in frontal crash simulations with restrained anthropomorphic test devices (ATDs) in non-airbag situations. This study investigated the biofidelity of this contact by evaluating the impact response of both the chin and manubrium of adult post-mortem human subjects (PMHSs). The adult PMHS data were scaled to a 10-year-old (YO) human size and then compared with the Hybrid III 10YO child (HIII-10C) ATD response with the same test configurations. For both the chin and manubrium, the responses of the scaled PMHS had different characteristics than the HIII-10C ATD responses. Elevated energy impact tests to the PMHS mandible provided a mean injury tolerance value for chin impact force. Chin contact forces in the HIII-10C ATD were calculated in previously conducted HYGE sled crash simulation tests, and these contact forces were strongly correlated with the Head Injury Criterion (HIC(36 ms)). The mean injurious force from the PMHS tests corresponded to a HIC(36 ms) value that would predict an elevated injury risk if it is assumed that fractures of the chin and skull are similarly correlated with HIC(36 ms). Given the rarity of same occupant-induced chin injury in booster-seated occupants in real crash data and the disparity in chin and manubrium stiffnesses between scaled PMHS and HIII-10C ATD, the data from this study can be made use of to improve biofidelity of chin-to-manubrium contact in ATDs.