This study investigated the fatigue behavior of glass fiber reinforced polymer composite and the changes in the physical properties and the structure of epoxy due to fatigue loading. Vacuum infusion process (VIP) was used to manufacture the glass fiber biaxial (0 , 90) reinforced epoxy composite. The tensile strength of the fabricated composite was 420.1 MPa. Tensile-tensile fatigue test was performed at 70%, 50%, 42%, and 35% of the tensile strength of fabricated composite. Damage mechanisms causing fatigue failure, namely, pull-out, debonding, delamination, and matrix cracking were examined by scanning electron microscopy (SEM) fractography. Pull-out of the fibers and debonding were more at the lower load level, while delamination and matrix cracking were more prevalent at the higher load level. Fourier transform infrared spectroscopy (FTIR) analysis revealed changes in the O H and C H stretching aliphatic peaks of the composite after fatigue loading. Decomposition temperature and the glass transition temperature of the epoxy in the composite also decreased due to the applied fatigue loading.

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