Computational Investigation of Rear-Seat Occupant Protection for Midsized Males in High-Speed Frontal Crashes

The advancements in vehicle safety have mainly focused on front-seat occupants. With an increasing focus on autonomous and shared mobility, there is a considerable need to improve occupant protection in rear seats. This study presents a computational investigation to evaluate the safety performance of modern vehicle rear seats. Full-body injury risks were calculated for midsized male occupants seated in the rear seat during frontal crashes, employing the Global Human Body Models Consortium (GHBMC) 50th male (M50-O) finite element (FE) human body model (HBM). Four modern vehicle rear-seat models, including both conventional and advanced restraint systems, were evaluated under New Car Assessment Program crash pulse (ΔV of 56 kph). Injury risks for the head, neck, thorax, abdomen, and femur were analyzed, with particular attention to the risk of submarining, where the pelvis slips beneath the lap belt during high-speed crashes. The predictions of FE simulations showed agreement with postmortem human surrogate (PMHS) test data in terms of occupant kinematics and injury predictions. While some kinematic differences were observed between the GHBMC model and PMHS data, particularly in vertical excursions, the HBM successfully captured the submarining response across different seat designs. This indicates that the GHBMC model provides a tool for assessing rear-seat injury risks. The overall risk of serious injury ranged from ∼60% to nearly certain, highlighting significant room for improvement in rear-seat safety. Advanced restraint systems and steeper seat pan angles showed to have the potential to reduce injury risks, though other factors play a role as well.