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Abstract
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This research concerns the impact of fatigue loading on the mechanical property of green sisal fiber-reinforced polyester composite with emphasis on the impact of matrix stiffness. Composite specimens were prepared using two different hardener-to-resin ratios 1:75 to 1:150, which are different levels of matrix stiffness. Fatigue tests were conducted on bending for various cycles: 50,000, 100,000, 250,000, and 1000,000. Then, tensile tests were performed to identify the change in stress, strain, Young's modulus, and rupture work. The results show it is apparent that the progressive development of damage and extensive reduction in the mechanical properties is brought about by fatigue loading, particularly at high fatigue times. Low hardener composition on use (1:150) composites were fatigue resistant with higher residual stress and higher modulus retention than high hardener composition (1:75) composites. Microscopy indicated progressive failure mechanisms such as surface cracks, fiber deformation, interface debonding, fiber pull-out, and matrix rupture. ANOVA analysis confirmed that fatigue life and matrix stiffness are key parameters for mechanical degradation. Our finding shows the complex interaction between the sisal fibers and polyester matrix with damage processes and microstructural modifications under fatigue loading. Furthermore, the current study explores the potential enhancement of fatigue resistance of sisal-polyester composites and presents some engineering design recommendations for their applications in different domains of engineering. Overall, this work contributes to the development of more environmentally friendly and dependable composite materials.
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