Mechanical Strength Analysis and Damage Appraisal in Carbon/Perlon/Epoxy Composite for Orthopedic Prostheses

Nowadays, the choice of composite materials to manufacture medical orthopedic prostheses is largely accepted for its intrinsic resistance, ease of molding and machining, compatibility with human skin and also for economic aspects. Because of population aging and the need to repair broken or damaged human members, composite materials offer a very large variety of solutions to strongly satisfy such demands in the form of prostheses. These materials consist mainly of a consolidated resin reinforced with glass, carbon or natural fibers. Advantageous properties made them the most requested materials in the manufacturing of prosthetic devices for orthopedic use by people with movement disabilities. The present work considers a composite material made with carbon fibers, perlon (insulating layer) and an epoxy-based orthocyclic laminating resin. Both mechanical and morphological properties are analyzed. It is found that the composite made of carbon fibers/perlon/epoxy resin lower has lower mechanical resistance compared to carbon fiber/epoxy resin composite, but its adherence and its contact with human skin are ameliorated. For the fibrous reinforcements, carbon, glass or perlon, the mechanical properties on the proposed composite material (PVA- (C-4P-C) -PVA) are comparable to literature values. Based on uniaxial tensile tests, the elastic modulus is 626 MPa and the yield stress which is 57 MPa. Finally, SEM observations revealed that both composites exhibit similar damage mechanisms with higher intensity when perlon is present. This is due to the nature of the perlon in the composite material which exhibits more anisotropy. The main encountered damage mechanism is laminate decohesion which takes places between carbon plies and perlon. Such condition contributes to more interlaminar delamination and more brittleness of the material when subjected to high loads.