Development Of A 6-Year-Old Child Lower Limb Finite Element Model And Analysis Of Pedestrian Impact Responses

With the rapid development of automobile industry, traffic injury has become one of the important factors that threaten the safety of human life. Due to the lack of effective protection measures, pedestrians are vulnerable in collision accident and take a large toll in traffic death. Comparing to adults, the consciousness of safety protection for children is relatively vague. However, researches on child traffic safety have not been addressed as they should be. Therefore, it is necessary and helpful to develop a finite element model of child that possesses a high-biofidelity, to study and understand the injury mechanism of children in traffic accidents.In this paper, the geometry of the lower limb of a 6-year-old child was extracted based on CT images. Different tissues such as the femur, tibia, fibula, patella, foot bones, muscles and skin were identified by threshold segmentation method. Then, surface smooth and patches construction were processed using reverse engineering software. The lower limb finite element model of the 6-year-old child was developed by using the meshing software. Model validations were carried out by three point bending tests for the long bone and muscles, shear and bending under low and high load simulation tests for the knee joint.Parametric studies were carried out by the application of the model. First, the influence of material parameters on children’s long bone fracture was analyzed. Study found that the low elastic modulus of children’s bone increased bone flexibility and reduced the risk of fracture to some extent. Secondly, the influence of equivalent muscles and real muscles on injury assessment was examined. The simulation of the real muscles gave a better understanding of the real injury mechanism of lower limb during impact. Finally, effects on dynamic response of the lower limb for different collision height and angles were studied. The results showed that impacts on the lower thigh and the knee presented higher risk of injury. The ±45 ° oblique collision caused damage to the lower limb in a more complex and serious way.In conclusion, a detailed anatomical finite element model of lower limb of a 6-year-old child was developed in this research. The model was used to study the injury mechanism of the lower limb of a 6-year-old child. This study provided a basis for scientific data for further children’s lower limb injury research. It can also provide a reliable basis for injury countermeasure for children in lower limb injury prevention in vehicle safety design.