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Abstract
A non linear boundary element code capable of treating contact problems with nonlinear friction and initial interference between two bodies is initially developed and validated. It is then used to perform thorough stress analysis of a biomechanical problem: a pull-out test.
In contrast to the finite element method, the elaboration of the contact problems does not need a special link element to ensure the compatibility of stresses and displacements. Since the degrees of freedom in the boundary element problems are the displacements and the tractions on each element, the compatibility is dealt directly with some continuity equations at the interface.
The pull-out tests are simulated by two press-fitted cylinders. A number of interface friction properties (Coulomb, bilinear and non linear friction) and boundary conditions are studied to investigate their influence on the displacements, stress distribution at the interface and the final resistance of the interface. The effect of the press-fit combined with the presence of a horizontal load are also studied. Comparison of the present predicted results with those of the experimental and finite element studies demonstrates a reasonable agreement.
The stress distribution is not uniform on the interface and is influenced by different configurations. The ultimate resistance of the interface is very dependent on the choice of materials and boundary conditions. For the same combination of material and boundary conditions, the application of a combined load (axial + shear in equal proportion) decreases the final resistance of the interface by 20% compared to the axial loading alone. (Abstract shortened by UMI.)