Data
Graphs below depict the severity of the displacement that is directly correlated to the polymers’ material properties. The mechanical properties of PLA 80 (green/middle) and PLA 100 (blue/bottom) are virtually the same, but their infill rates differ: 80 (80%) and 100 (100%). However, Nylon 80 (red/top) differs substantially from both PLA 80 and 100, in that its Young’s Modulus (2000 MPa) and compressive strength (80 MPa) are substantially lower. PLA’s Young’s Modulus (3500 MPa) and compressive strength (95 MPa) cause it to be more rigid and subsequently less elastic than Nylon 80. This decreased elastic capability can be observed by the less severe slope of PLA 80 and 100 and the increased displacement of Nylon 80 in both the heel and connection tab graphs depicted below.
Above compare version 1 (initial design) of the prosthesis to version 3 (final design). Shows the level of displacement of the connection tab. This is important because the angle at which the connection tab bends is vital to the biocompatibility of the prosthesis. The ideal angle of the connection tab displacement is 27 degrees; this facilitates the most fluid stride. Version 1 achieved an 11.9 angle of displacement from origin, approximately 56 % deviation from the ideal angle. Version 3 achieves an angle of 26.8 degrees, approximately .6 % deviation from the most biocompatible prosthesis. This shows how prototyping and design analysis; coupled with an understanding of yield radii, cantilever beams and material properties; contribute to the biocompatibility of the prosthesis.
Above compare version 1 (initial design) of the prosthesis to version 3 (final design). Shows the heel tab’s level of displacement. The ideal angle of the heel tab displacement is 36 degrees; this facilitates the most fluid stride. This angle was perfected so that the through stride and the initial impact of the step were as close to the ideal angle as possible to facilitate maximum momentum conservation. Version 1 achieved a displacement angle of 23.4 degrees with respect to the origin, approximately 36 % deviation from the ideal angle. Version 3 achieves an angle of 34.2 degrees, approximately 5 % deviation from the most biocompatible prosthesis.