Applicability of Neck Injury Criteria Critical Intercepts for Human Body Finite Element Models
ISSN: 2327-5626, e-ISSN: 2327-5634
Published August 25, 2021 by SAE International in United States
Citation: Johnson, D., Devane, K., Koya, B., and Gayzik, F., "Applicability of Neck Injury Criteria Critical Intercepts for Human Body Finite Element Models," SAE Int. J. Trans. Safety 9(2):233-261, 2021.
The critical intercepts used for the Neck Injury Criterion (Nij) have not been assessed in computational human body models. Under matched-pair conditions, the response of the head-neck complex was compared between the Livermore Software Technology Corporation (LSTC) Hybrid III (HIII) and Global Human Body Models Consortium’s (GHBMC) 50th percentile, detailed male occupant (M50-O) models. The head and neck of the M50-O and HIII were subjected to the dummy performance calibration test procedure for flexion and extension. As a nominal condition, the HIII model met all calibration specifications. Operationalization of the M50-O’s initial position was defined by equivalent head CG location to the HIII and subsequently compared at nominal, ±10%, ±20%, and ±30% of pendulum displacement. Kinematics of the head CG, forces and moments of the upper neck, and changes in neck angle were post processed and compared between the models. The sagittal velocity of the head CG was found to be greater for the M50-O in flexion and for the HIII in extension. Coupled with this trend, greater force and moment exhibited a direct, positive correlation with maximum, sagittal head CG velocity. Correlates of force and moment between the models in both flexion and extension have been derived from the results of this work. As an extension of this finding, modified intercepts of the Nij for application to the M50-O were plotted. These human model-specific critical intercept values may be understood as a consequence of the natural lordosis exhibited by the cervical spine of the M50-O, a feature absent in the HIII. The correlates and conclusions of this work are limited to the range of induced forces and moments, as well as loading rate. Future work will seek to compare the response of the HIII and M50-O models in combined compression-flexion and compression-extension loading.