Structural analysis of a Four-bar linkage mechanism of Prosthetic knee joint using Finite Element Method

The main objective of this study is to check and validate an existing structural design of above knee prosthesis developed by hosmer knee. A CAD model for above knee prosthesis has been developed and Finite element analysis has been done for static and cyclic load. Selection of reference planes and load line positioning has been done using International Organization for standardization (ISO) test procedure. This test is titled as Prosthetics Structural testing of lowerlimb prostheses Requirements and test methods (ISO 10328:2016). A test model have also been designed and fabricated in the lab for the static and cyclic loading. Six trials were conducted in order to check the design and load-bearing part of the prosthesis. Prosthetic Knee joint also performed a deep flexion for the maximum stress condition. A finite element model (FEM) imparting the induced stress distribution in the prosthesis to ensure its safe performance in the fatigue life has been developed. Strains computed in the mechanism from the FEM validate the values obtained from the experimental data obtained in static and fatigue test conducted using ISO 10328:2016 procedure. The average percentage error of simulation in all testing conditions is within 20%. The knee prosthesis is safe under the physical structural test without any failures as calculated in the simulation.