Design Modification of an Affordable Prosthetic Knee Based on DFMA and Static Analysis

In Indonesia, the need for prosthetic knees is increasing due to the large number of amputees. However, the price of the prosthetic knee is rather expensive. Therefore, Biomechanics Research Team of ITB has been developing affordable prosthetic knee. This work presents the improvement of the previous design of the prosthetic knee which include the Design for Manufacture and Assembly (DFMA) analysis and static analysis. The calculated DFA index is 16.48% which means the assembly time is efficient. DFM analysis results indicate that cost to manufacture a prosthetic knee is around US$39. However, the design fails due to transfer of force from the lower body of the prosthetic knee to the linkages. Therefore, there is a need to modify the design and modification of the male pyramid adapter and the location of the adapter relative to the pylon are proposed. Static analysis shows that the maximum stress occurs on the snap ring of the prosthetic knee is 141.04 MPa, which is lower than its yield strength. The latest design has less number of components, obtained via DFMA analysis and also safe stress level.