A Study on Affections of Active Neck Muscle Force on Neck Injury Responses in Frontal Impact with Automatic Emergency Braking Conditions

Neck injury is one of the most common injuries in traffic accidents, and its severity is closely related to the posture of the occupant at the time of impact. In the current era of smart vehicle, the triggered AEB and the occupant's active muscle force will cause the head and neck to be out of position which has significant affections on the occurrence and severity of neck injury responses. Therefore, it is very important to study the influences of active muscle force on neck injury responses in in frontal impact with Automatic Emergency Braking conditions. Based on the geometric characteristics of human neck muscles in the Zygote Body database, the reasonable neck muscle physical parameters were obtained firstly. Then a neck finite element model (FEM) with active muscles was developed and verified its biofidelity under various impact conditions, such as frontal, side and rear-end impacts. Finally, using the neck FEM with or without active muscle force, a comparative study was conducted on the kinematics and injury responses of the neck in the frontal impact with AEB condition. The research findings indicate that the activation of cervical active muscle forces effectively reduces the displacement of the head's center of gravity prior to the collision and significantly decreases the relative angular displacements between cervical vertebrae during the collision. These dynamic response changes mitigate the injury severity of cervical vertebrae, ligaments, and intervertebral discs, thereby enhancing the biomechanical tolerance of the cervical structure to mechanical loads.