چكيده به لاتين
The lower extremities, including the Knee, Thigh, and Hip (KTH), account for a significant portion of accident-related injuries each year. Femur fractures are among the most common injuries sustained by occupants. Therefore, this study investigates femur fractures resulting from dashboard impacts. To enhance simulation accuracy, the mechanical properties of the bone are considered anisotropic. For this purpose, a femur and pelvis bone were modeled using Mimics and 3-Matic software and analyzed via finite element analysis. In the first phase of the project, a rigid body impacts the femur and pelvis bones at three speeds: 7, 14, and 21, and the resulting stresses in the bones are examined. In the second phase, after selecting an appropriate hip implant for the patient and designing it, the femur bone is prepared for placement, and the prosthesis is implanted. Then, similar to the first phase, the dashboard impact at three different speeds is simulated. After examining the stresses on the described system in both phases, it is found that the femur bone or implant may have critical points. Therefore, the maximum compressive and tensile stress criteria are used to evaluate femur fractures, and the Von Mises criterion is used for implant fractures. According to the project results, it can be concluded that in the first phase, the fracture occurs in the femur shaft due to the tensile stress reaching its maximum value. In the second phase, at all speeds, the fracture occurs at the bone-implant junction. The mechanism of this fracture is identified as the compressive stress reaching its maximum value. Comparing the phases, the second phase shows a much quicker fracture, occurring 0.2 milliseconds post-impact for the model with the prosthesis, whereas, for the model without the implant, it occurs between 1.06 to 5.6 milliseconds. Additionally, in the model with the implant, the stresses are very close to causing failure, but the fracture happens shortly after the femur bone fracture. This research can provide valuable insights to automotive and implant designers for improving their product designs. Moreover, this study can offer new perspectives on lower limb injuries in accidents and severe shocks.
