FATIGUE CHARACTERISTICS OF 3D-PRINTED CARBON FIBER NYLON 12 (CF/PA12) HIP IMPLANTS

Carbon fiber composite materials are frequently employed in components where cyclic loads could result in fatigue failure. The primary objective of this study was to assess the fatigue behavior of fused modelled, carbon fiber nylon 12 (CF/PA12) hip implants. Structural analysis was carried out using analysis of systems (ANSYS 19 R2) to evaluate the safety of a hip implant design. The hip implant was then printed using a Fusion 3 printing machine, and dog-bone fatigue test specimens were machined and cyclically tested at 50, 60, 70, and 80% of the ultimate tensile stress. Finite element analysis revealed a maximum von Mises stress of 24.401 MPa in the hip implant, which is well below the ultimate strength of 71 MPa for the CF/PA12 implant. This indicated that the CF/PA12 hip implant was resistant to fatigue failure. The cyclic fatigue life results were 5,080,709 cycles at 1043.3 N, 1,146,842 cycles at 1251.9 N, 585,731.50 cycles at 1460.6 N, and 212,237.50 cycles at 1669.2 N. The International Standard Organization requires hip implants to have a minimum fatigue life of 105 cycles under loadings from 300 N to 3000 N. The CF/PA12 composite met this standard for all tested loads, indicating superior fatigue performance.