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Updated: Jan 17, 2026
A Test Bed to Examine Helmet Fit and Retention and Biomechanical Measures of Head and Neck Injury in Simulated Impact
Published on: September 21, 2017
Research on occupants out-of-position and whiplash injury under automatic emergency braking
Jie Huang1,2, Chengyue Jiang3, Guojie Wang1,2
1State Key Laboratory of Intelligent Vehicle Safety Technology, Chongqing, China.
Objectives:
Automobile manufacturers are gradually incorporating autonomous emergency braking (AEB) systems into their vehicles. However, AEB may result in the occupant being out of position, increasing the risk of injury. Additionally, the accident analysis of occupant injury in the scenario where AEB Works First, Followed by Rear Impact (AWFFRI), is limited. This article aims to investigate the occupants' out-of-position response and whiplash injury in AWFFRI.
Methods:
The Total Human Model for Safety (THUMS), which was proposed and validated by the Toyota company, was used to provide a baseline for human injury. Furthermore, THUMS and BioRID II dummy models were utilized to develop numerical sled test models. The BioRID II sled test finite element (FE) models were developed and refined through a physical experiment. Then, the difference between BioRID II and THUMS dummy kinematics in the out-of-position scenario was analyzed. The force, tension, acceleration, NIC, strain and stress of the BioRID II and THUMS models in traditional and AWFFRI situations were measured. The effect of AEB on each dummy was analyzed.
Results:
The BioRID II dummy exhibits a 19 mm lower head displacement than the THUMS model, resulting in a 13% difference. In the AWFFRI scenario, the AEB, which results in a -8.8 m/s2 lowest acceleration, will last for 0.342 s, followed by a rear-end collision with 97.6 m/s2 maximum acceleration. The BioRID II and THUMS models in the AWFFRI situation illustrated higher whiplash injuries than the traditional scenario, with the upper neck shear force (164.79 N), upper neck extension tension (830.46 N), T1 average acceleration (137.84 m/s2), NIC (45.68), and interspinous ligament strain (0.871) increased by 158.45%, 96.62%, 7.23%, 89.70% and 108.9%.
Conclusions:
The BioRID II dummy response in the AWFFRI scenario exhibit an increasing trend compared to those in the traditional whiplash scenario. For the BioRID II dummy, the upper neck shear force, upper neck extension tension, as well as NIC exhibit the most significant increase. Additionally, the upper neck shear force, upper neck extension tension, T1 average acceleration, and NIC of the BioRID II dummy exceeded the thresholds, indicating that the occupant may be at risk of sustaining a neck injury. For the THUMS model, the stress and strain on the dummy skull, cervical vertebrae, and ligaments are higher in the AWFFRI scenario compared to the traditional whiplash scenario. Furthermore, the interspinous ligament injury stain (0.871) exceeds the threshold (0.68), indicating a greater risk of ligamentum flavum injury. The results obtained in this study highlight a concern for a potential increase in whiplash risk associated with AEB when followed by a rear impact.
