Translational and Rotational Head Kinematics in Side Impact

Regulatory tests use translational head accelerations and its derived variable HIC (head injury criterion) as the criteria for automotive vehicle crashworthiness evaluation. The FMVSS standard sets HIC₃₆ of 1000 as the threshold for frontal impact protection. On the other hand, rotational head kinematics, such as rotational accelerations and velocities, has been attributed to brain injury in the motor vehicle environment for more than six decades [1–5]. As documented in recent real-world case studies, severe brain injuries without skull fracture, such as diffuse axonal injury, can result from rotational head motions in side impacts even at low change in impact velocity [6, 7]. Because the HIC only accounts for the translational head accelerations, there is no clear evidence showing there is a direct correlation between translational and rotational head acceleration. Therefore, it is important to quantify the correlation between head translational and rotational accelerations and HIC, in side impacts. Consequently, the current research was designed with this purpose.