Mechanical Behaviour of Materials for External Biomechanics Application: Study on the Fatigue of Polymers: PLA and PETG

• Main Author: Martins, Miguel Confraria
• Publication Date: 2023
• Format: Master thesis
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10362/161479
• topic: Additive Manufacturing; FFF; Polymers; Biomedical Applications; ensile Testing; Fatigue Testing; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Mecânica

This study investigates the mechanical behaviour of various polymeric materials pro- cessed through fused filament fabrication (FFF) for potential external applications in biome- chanics. The research objectives were twofold: firstly, to assess the materials' suitability for bio- mechanical use through uniaxial tensile testing, and secondly, to evaluate their fatigue re- sistance, specifically focusing on PLA and PETG materials. The uniaxial tensile tests provided insights into parameters, such as maximum tensile strength, modulus of elasticity, and strain at failure values, suggesting the materials' potential for general biomechanical applications. However, fatigue testing unveiled limitations in PETG, as indicated by the low fatigue resistance depicted in Wöhler curves. These findings suggest that this material may not be well-suited for continuous and long-term use in biomechanical components. Fractography analysis further revealed critical features, such as fibre arrangements, com- pression issues between layers and inadequate adhesion, voids in fibre connections, and frac- ture zones, shedding light on failure mechanisms.