A HUMAN MODEL FOR LOW-SEVERITY REAR-IMPACTS

Neck injuries resulting from rear-end collisions rank among the top safety problems and have serious implications for society. In an attempt to minimize the severity of neck injuries in such accidents, an increasing number of studies to evaluate the effectiveness of head restraints has been performed. In these studies, volunteers, crash test dummies, and mathematical dummy models were used. In addition, a limited number of mathematical models of the human body was used. However, to the best of our knowledge, these models were not validated in an environment comparable with a rear-end collision. The objective of this study is to develop a mathematical model of a seated occupant and to better understand the biomechanical response of the spine and the occupant's interaction with the seat during rear-end collisions. For this purpose, a 3D mathematical model of a 50th percentile sitting adult male is developed for use in simulations of rear impacts. Special attention is paid to the modelling of the spine, including the neck, and the occupant's interaction with the seat. To obtain insight into its biofidelity, the model's response is compared with rear-end sled tests with volunteers and human cadavers at a ¿V of up to 30 km/hr. The model is then used to study and quantify the motion of the spine in low and medium severity rear-end collisions. This study revealed that, during the ''torso loading phase'', the pelvis was lifted from the seat while the vertical motion of the T1 vertebral body relative to the vehicle was slight. Spinal compression occurred during this phase, but it remained slight. Although a thorough validation of the model developed was not possible due to lack of experimental data, it can be concluded that this model has the potential to become a powerful tool for parametric studies to aid in a seat design process.