Optimised Analysis, Design, and Fabrication of Trans-Tibial Prosthetic Sockets

Abstract

In this study, two laminated composite materials were used to manufacture residual-limb prosthetic sockets using the vacuum moulding method. Acrylic was used as a matrix material and reinforced with two types of fibres, perlon and carbon. The mechanical properties were calculated using tensile and bending tests, and socket failure characteristics at room temperature were determined by using a fatigue test. F-socket apparatus was used to measure the interface pressure between the residual limb and socket in two subjects with unilateral trans-tibial amputations using patellar tendon bearing prosthetics (PTB). The ANSYS program was used to calculate the deformation, maximum principle stress, and safety factors. The results showed that laminations laid-up from eight layers of perlon plus four layers of carbon gave optimum mechanical properties. Comparing this lamination with other laminations of six layers of perlon plus two layers of carbon, in spite the minimal increase in perlon and carbon layers (from eight layers to twelve layers), the ultimate stress increased by 12.46%. The Young’s modulus of a lamination with six layers of perlon and four layers of carbon was 3.66 GPa, higher than other laminations investigated. A high Young’s Modulus will result in a total contact socket that produces the best comfort level for patients. The maximum principle stress and total deformation increased with an increase in the length of stump: The maximum principle stress of a long socket increased by 0.3% of medium stress, while the total deformation of the medium socket was lower than that of the long socket.