Development of a finite element-multibody coupled model for child brain injury prediction in electric two-wheeler accidents

ABSTRACT Frequent electric two-wheeler (ETW) accidents raise collision safety concerns for child passengers. However, traditional multibody (MB) and finite element (FE) modelling methods struggle to balance simulation accuracy and efficiency when predicting child injury. This study aimed to develop an FE-MB coupled model for predicting brain injuries in child passengers of ETW during ETW-to-sedan collisions. The child model integrated an FE head-neck model with an MB child model, while the sedan model combined an FE hood with an MB sedan model. The validity of the coupled child model was confirmed through simulations of head and face impacts, and the influence of mesh size, contact gap and connection mode was analyzed. Furthermore, the coupled model’s applicability to ETW-to-sedan collisions was validated via accident reconstruction. Subsequently, the offset between the hoods in FE and MB models of the coupled sedan was examined, along with its effects on kinematic responses, brain contusions, and diffuse axonal injuries (DAI) in children. Results demonstrated that the coupled child model achieved peak force errors within 5% of both FE and MB results for head and face impacts, while requiring less than 10% of the full-scale FE computation time. Additionally, the mesh size primarily affected the peak force, while the contact gap and connection mode influenced the later phase of the head collision. Compared to X-direction hood offsets, Z-direction offsets exhibited a more pronounced influence on kinematic responses and the risks for brain contusions and DAI in children.