RESUMO
Objective The purpose of this paper was to use a new biphasic poroelastic tibia model to develop a two-dimensional numerical method for simulating impact responses of human tibia in car-pedestrian accidents. Methods The geometry of tibia model was reconstructed from CT scans of the left tibia of a living human volunteer. A poroelastic approach was utilized to establish the governing equations of the model and the finite element method was applied to solve these governing equations. Both cortical and cancellous components of tibia were represented using a poroelastic material model consisting of solid phase (matrix) and fluid phase (marrow). A lateral-medial impact direction was selected in the simulation analysis and the impact responses of the pedestrian tibia during 0-200 ms were analyzed. Results The bending deformation of the tibia predicted by the computer simulation was primarily concentrated on the impact zones. The displacement response of Node 107 in the impact zone indicated a peak displacement of -6 mm at around 75 ms, and the significant time delay between the impact force and the displacement response of the skeleton. The axial stress response at the center of element E77 in the impact zone indicated a peak stress of 140 MPa at around 30 ms,and the significant time delay was observed between the impact force and the axial stress response of the skeleton, too. Conclusion This research developed a two-dimensional numerical method for simulating impact responses of human tibia in car-pedestrian accidents. It was able to approximately simulate the bending deformation, lateral displacement response and axial stress response of pedestrian tibia in the impact zones,and the effects of the fluid phase on the solid phase. More in-depth investigation is helpful to further the biofidelity of tibia dynamics model.