Desalegn Wogaso (PhD)Eyobel Mulugeta (PhD) Co-AdvisorBetselot Tesfaye2025-05-142025-05-142023-03https://etd.aau.edu.et/handle/123456789/5454Prosthetic shank is one of the prominent parts of prosthetic leg that transfers load from prosthetic socket to the foot section. Nowadays, it is common to use composite materials for prosthetics and orthotics applications. This research focuses on the synthesis and characterization of properties of crystalline nanocellulose (CNC) powder and investigating its effect on the mechanical and physical properties of E-glass fiber - epoxy composite for prosthetic shank applications. Different properties including tensile, impact, flexural, water absorption, thermographic, density and surface morphology of a hybrid composite are investigated. The research further targets to test the suitability of developed composite material for prosthetic shank applications. Extraction of CNC powder is performed using chemical extraction technique which involves alkali treatment, delignification, bleaching and acid hydrolysis. Crystallinity of CNC particles are determined at 2 values of 19.890, 44.040, 64.340 and 77.510. Crystallite size of these powders is found to be approximately 13 nm by x’pert high score software from the XRD analysis. FT-IR was conducted to determine fiber-fiber and fiber-epoxy chemical bonding interaction. Thermal properties of CNCs are examined using thermographic analysis (TGA) approch and the result reveals a three-stage decomposition of CNC powders in temperature ranges of 62-240 oC, 240-360 oC, and 360-625 oC, respectively. Hand layup method with light load compression is employed to fabricate hybrid composite specimens with different % CNC powder. Mechanical and physical tests are carried out to determine the composite’s performance according to ASTM standards. The results reveal addition of CNC powder enhances the overall performance of the composite, and composite specimen with 8wt% CNC powder shows superior mechanical and physical properties. The numerical values obtained was tensile strength of 127.8Mpa, compression strength of 91.1Mpa, flexural strength of 251Mpa, and impact energy of 6.83J. Further, selected composite is modeled for the prosthetic shank application using finite element software, ANSYS 2022, and maximum equivalent von Mise’s stress of 0.82598 MPa and deformation of 0.054065 mm are obtained. Based on the overall findings and analysis, it is highly recommended to develop and use hybrid E-glass fiber – CNC - epoxy composite as a substitute material for prosthetic shank applications.en-USCrystalline nanocelluloseprosthetic shankhybrid composite E-glass fiberepoxy resinThesis