Effect of Embedded Wrinkle Defects on the Tensile Performance and Damage Mechanism of Glass Fiber Reinforced Composites

ABSTRACT Wrinkle defects are inevitable in composite laminates due to limitations in current manufacturing processes, and these defects significantly affect the mechanical behavior of the structures. To investigate the damage mechanism of composite laminates with wrinkle defects and the influence mechanism of wrinkle defects on the mechanical properties, a simple “stringer” method is used to fabricate embedded wrinkles that reproduce the unflattened prepreg condition during layup. The quasi‐static tensile tests were conducted on specimens with six types of wrinkle defects as well as on non‐wrinkled specimens. Damage evolution during testing was characterized using digital image correlation (DIC) and scanning electron microscopy (SEM). Moreover, the strain concentration factor (SCF) was derived from DIC data, revealing a strong linear correlation with strength degradation. Quasi‐static tensile tests on glass fiber reinforced polymer (GFRP) laminates with six types of wrinkle configurations varying in width and spacing reveal that compared with non‐wrinkled specimens, wrinkles reduce the tensile strength by up to 35%, with two closely spaced large wrinkles exhibiting a more pronounced reduction in tensile strength. DIC analysis demonstrates that wrinkles disrupt strain uniformity, concentrating it in wrinkle valley regions. The failure mode shifts from explosive fiber bursting in wrinkle‐free specimens to localized fracture within wrinkles, driven by fiber breakage and interfacial debonding.