Development Of Chinese50^th Percentile Human Lower Leg Model And Study Of Bone Fracture Properties

Due to the obvious advantage, the finite element (FE) methods have become one of the main tools for the study of vehicle crash safety. As the main tool of traffic injury biomechanics research, the computational and bionic accuracy of lower extremity FE model, experienced development of a long time, has advanced greatly. It was used in the optimization of vehicle, reconstruction of accident and study of injury always.But there are also some questions about the current model. Firstly, the model based on the anthropometry of Euro-American people may have some differentiation. Secondly, all of the current lower limb models were developed with a total muscle block that has a problem in the simulation of muscle active force. So it is crucial to establish the Chinese50th percentile male lower extremity FE model with detailed muscle bunches.So the modeling method of Chinese lower limb was proposed, based on the previous studies, and used on the development of the Chinese50th percentile lower leg model. The anthropometry data of Chinese50th percentile male lower limb were studied based on the previous literature. Taking advantage of the scanning of CT and MRI data, the geometry of bones and soft tissue were derived. On this basis, the meshing model was generated including foot bones (26chunks), tibia, fibula, muscle bunches (11bundles) et al. Then the established lower extremity meshing model was scaled by the anthropometry. So the meshing model of Chinese50th percentile was constructed.On this basis, the defining of part, property and material was processed. Focusing on the characters of the traffic accident injury of lower limb, the FE model was validated with the quasi-static and dynamic3-point bending experiments and the axial compression tests. In those validations, the tibia, fibula and lower leg was loaded in different direction, location and speed.The results showed that the dynamic property was coincident well between experiment and FE model and the peak force and corresponding time was matched preferably. The fracture moments (proximal:308.6N·m, middle:233.3N·m, distal:218.1N·m) of tibia were also within the limits of tolerance (254±71N·m). The accuracy and bio-fidelity of established FE model was proved. So the proposed modeling method of Chinese human lower limb has high application value. In the end, focusing on the crushing before fracture in the contact area of3-point bending with rigid compactor of tibia validation, experiments using pig rear leg bone were conducted. The subject-specific FE model was established to study the generation procedure and corresponding influences of crushing with the SEM technique used. The differences of crushing in test and experiment were analysis and the effective way to avoid the effects of crushing was studied.The results of crushing test and simulation indicate that crushing leads to the layering of crushing area and deflection of fracture path. The vibration of compact force of experiments was less than subject specific model simulation. Furthermore, the method, removing element elimination option on contact area, was certified reasonable to avoid the influence of force vibration. Those could be the reference for the later work to validation of FE model.Furthermore, the lower leg model was applied to assess the effects for adjacent joints after three type of ankle fusion. The results showed that the anterior compression arthrodesis of ankle was the best fusion way for the lowest possibility of adjacent joint arthritis after treatment.