Comparison of head-neck responses in frontal impacts using restrained human surrogates

The objective of the study was to evaluate the head and neck kinetics of three-point belted Hybrid III dummy and Test Device for Human Occupant Restraint (THOR) in frontal impacts, and compare their responses with data from post mortem human subjects (PMHS). Surrogates were placed on a buck, capable of accommodating different anthropometry with similar initial positioning. Duplicate tests were conducted at low, medium, and high (3.6, 6.9, and 15.8 m/s) velocities. Upper and lower neck forces and moments were determined from load cell measures and its locations with respect to the ends of the neck. Head excursion-time responses were more repeatable in the Hybrid III dummy than the THOR dummy. Hybrid III dummy response was more rigid in the sagittal plane. Peak THOR motions were closer to PMHS. Based on times of occurrences of peak excursions, THOR was closer to PMHS at all velocities, while Hybrid III dummy showed biofidelity at the medium and high velocities. Controlled positioning and testing with different surrogates provide an evaluation of inter-subject responses. THOR was more likely to "get the head where and when it needs to be" in frontal impacts. With the importance of testing at lower speeds due to recent recognition of real-world injuries, these data suggest that THOR may be an optimal dummy for frontal impacts. Comparisons of head-neck kinetic data with PMHS are valuable in frontal impact injury assessments.