Biofidelity Assessment of the GHBMC M50-O Seated in a Honda Accord Seat in a Rear-Facing Configuration during a High-Speed Frontal Impact

<div>Vehicles equipped with automated driving systems (ADS) may have non-traditional seating configurations, such as rear-facing for front-row occupants. The objectives of this study are (1) to generate biomechanical corridors from kinematic data obtained from postmortem human subjects (PMHS) sled tests and (2) to assess the biofidelity of the Global Human Body Models Consortium (GHBMC) 50th male (M50-O) v6.0 seated in an upright (25-deg recline) Honda Accord seat with a fixed D-ring (FDR) in a 56 km/h rear-facing frontal impact. A phase optimization technique was applied to mass-normalized PMHS data for generating corridors. After replicating the experimental boundary conditions in the computational finite element (FE) environment, the performance of the rigidized FE seat model obtained was validated using LSTC Hybrid III FE model simulations and comparison with experiments. The most recent National Highway Traffic Safety Administration (NHTSA) Biofidelity Ranking System (BRS) method was used to assess the biofidelity of the GHBMC M50-O. The occupant response score for GHBMC was 2.00. The average normalized root mean squared deviation (NRMSD) for seat reaction loads in the GHBMC simulation was less than 10%. Peak T-spine accelerations (avg. BRS = 2.28) and anterior-to-posterior (AP) chest deflection (BRS = 2.61) were underestimated. No rib fractures were predicted in the GHBMC using the default failure strain criteria of 1.8%; however, fractures were predicted in the 3rd rib (both left and right sides) using an updated failure strain criteria of 0.52%. Ramping up the seat back, as indicated by pelvis Z-displacement, was underestimated using a coefficient of contact friction of 0.2 (BRS = 3.65) but improved using a coefficient of 0.1 (BRS = 1.44). Local strain hotspots were predicted at the pubic rami locations in the GHBMC, corresponding well with fracture sites in the PMHS.</div>