Mechanical behavior of a lower limb prosthetic socket made of natural fiber reinforced composite

Transtibial sockets are commonly made of composites reinforced with expensive synthetic fibers such as carbon or glass fibers. It would be very beneficial to replace conventional fibers with the natural ones produced locally using an abundant wild plant like alfa (Stipa tenacissima) fiber that is economically sustainable and environmentally friendly. This work is aimed at studying the static and dynamic behavior of transtibial sockets produced from alfa and carbon fibers. The ultimate strength obtained during the static test on the carbon fiber socket and the alfa fiber socket is 3,400 and 2,900 N, respectively. Fatigue testing on the alfa fiber socket yielded a fatigue life of about 2,325,000 cycles. Locally produced alfa fibers could be used as reinforcement of composite materials in orthopedic applications such as transtibial sockets. This could make prosthesis more affordable and serve as basis for design of new standard sockets as a result of fatigue and strength data. Further mechanical viability study should be performed to ensure the feasibility of using alfa fibers in sockets.

Alfa fibers for Cereplast bio-composites reinforcement: Effects of chemical and biological treatments on the mechanical properties

The present work is a comparative study of the impact of Alfa fiber modifications on the Cereplast composites mechanical behavior. Various treatments have been employed, including mechanical, soda, saltwater-retting, hot-water treatments and enzymatic treatment using xylanase. Chemical and morphological analyses were carried out in order to determine the changes of the biochemical composition and the dimensions of fibers. Cereplast composites reinforced with Alfa fibers were fabricated using a twin-screw extrusion followed by an injection molding technique with a fiber load of 20 wt. %. Resulting materials were assessed by means of tensile, flexural and Charpy impact testing. Scanning Electron Microscopy analysis was carried out to investigate the interfacial properties of the composites. The results have shown a significant enhancement of mechanical strengths and rigidities for the xylanase-treated fiber composites, owing to the increase of cellulose content, the enhancement of defibrillation level and the improvement of matrix-fiber adhesion. The data proved that the technology of enzymes can be used as a powerful and eco-friendly approach to modify fiber surfaces and to increase their potential of reinforcement.