CHARACTERIZING THE FATIGUE BEHAVIOR OF SUSTAINABLE POLYMER MATRIX COMPOSITES FOR OFFSHORE STRUCTURAL APPLICATIONS USING THERMOGRAPHY: THERMOSET VS THERMOPLASTIC

Climate action plans greatly emphasize the energy sector, which turns the industry's attention towards offshore wind and tidal energy. However, the harsh and corrosive marine environment poses a challenge in terms of maintenance and durability of the steel structures. Composites are a suitable alternative due to corrosion resistance and high strength/weight ratio. Despite advantages, the industry refrains from the large-scale implementation of composites in offshore energy structures due to inadequate information on the performance of composites under various loading conditions, especially fatigue. With the aim of filling these research gaps, Horizon 2020 EUfunded project FIBREGY was initiated to enable extensive use of composites in offshore energy structures. As a part of this project, fatigue behavior of two sustainable polymers (Bio-based thermoset and infusible thermoplastic) matrix composites are characterized in this work. The behavior of the composites is studied by subjecting the composite to tension-tension fatigue loading, instrumented with thermography and an extensometer. The damage induced by fatigue loading is quantified in terms of heat dissipation and is used to estimate the fatigue limit using a rapid temperature stabilization method and is validated by establishing a fatigue (S-N) curve. This estimation is highly economical and can potentially be used by the offshore energy industry to swiftly screen various composite material options.