Modelling of a Composite Prosthesis for Quasi-Cylindrical Ligaments

A prosthesis for a cruciate ligament of the knee involves the problem of implanting a short and small spring for which the load-deformation response cannot be duplicated by any single man-made material. This work presents a model of the elastic behavior of a two material composite prosthesis made of high-strength fibers spirally wound around a soft elastic core. At each end of the core, the fibers are attached to a pulling device. Under a tension load, the fibers exert a pressure on the core which deforms radially, permitting the elongation of the prosthesis. This allows the achievement of large deformation while both the fibers and the core remain in the elastic domain. The high strength of the spring is provided by the high yield strength of the fibers. The results show the influence of the design variables on the deformation of the prosthesis.