Design and Analysis of Knee Joint for Transfemoral Amputees

Lower limb amputation not only reduces mobility but also results in significant impairment in quality of life. Microprocessor based transfemoral knee joints have gained significant importance in the last decade to not only restore cosmetics but also provide functionality comparable to real limb. One of the key issues in such devices is selection of the suitable material for manufacturing of knee joint to minimize chances of failure under various loading conditions, while at the same time ensuring the weight of the knee is within acceptable limits. The purpose of this research is to design a microprocessor-based knee joint and perform various static structural analysis for different materials to optimize strength to weight ratio of the proposed design. Initially, a model for the proposed microprocessor-based knee was developed in SolidWorks followed by displacement study and computation of von-mises stresses in Ansys Workbench. Different materials used in the analysis include Plain Carbon Steel, Stainless Steel 304, Aluminum 6061. Based on the results Aluminum 6061 was identified as a suitable material for manufacturing knee joint as it not only reduces weight of the knee joint but also the deformation and stress values are within acceptable limits. The minimum and maximum Von Mises stress of Aluminum 6061 was 559.9 Pa and 71.37 MPa respectively with tensile strength of 313 MPa.