Numerical Analysis of Taylor-Type External Fixator by Means of FEM

The main aim of this work was evaluate the displacements and strains and stresses in components of bone-fixator system using Finite Element Method. The Taylor-type fixator was chosen for the analysis as a one of the most technically advanced and the biggest therapy opportunities giving external fixator. Through the possibility of full and free manipulation of bone fractures (possible displacements and rotations in three independent planes) it is used in complex fractures therapy, complicated bones deformation therapy, distraction osteogenesis and much more. The first step was preparation of Taylor-type fixator geometrical model which was developed on a basis of a real model. To carry out an analysis it was necessary to develop a tibia bone model in which the fracture crack of 1mm breadth was simulated. Next a grid for finite-element method calculations was generated for the geometrical models. Subsequently it was necessary to specify and set the edge conditions to reflect appropriately the phenomena taking place in the real system. The system was loaded with axial force in range 100-1500N. Calculations were realized for fixator made of 316L steel. On a basis of obtained result, the highest values of reduced stress were observed in the fixator frame, in elements connecting telescopic strut with holder constrained in fixator full ring. For load

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> 1400N the yield stress of frame material was exceeding, what could cause its damage. In turn, stress in bone didn’t exceed its compression strength. The biomechanical analysis may form the basis for improving the geometry of analyzed fixator and optimising a selection of the mechanical properties of the material used to manufacture them.