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The failure of unidirectional and quasi‐isotropic carbon fiber reinforced polymer composite laminate with uniform and non‐uniform out‐of‐plane waviness defects were examined. Experimental tests and numerical simulations were performed for specimens with and without defects. Specimens with different types of waviness such as uniform embedded, non‐uniform hump and non‐uniform indentation were fabricated for testing their performance under three‐point flexural tests. Optical microscopic images were captured throughout the test to investigate the initiation and progression of failure in laminates. Three‐dimensional finite element (FE) models were built by considering actual specimen and defect geometric configurations obtained from optical microscopy. User material subroutine (UMAT) was developed and implemented in Abaqus/Standard to simulate intra‐ply failures as a continuum damage mechanism. The generated models are used to recognize damage initiation and progression during the flexural test. The experimental observations and FE simulation results are in good agreement for failure loads and damage mechanisms for different waviness cases.

Fibre waviness is frequently observed manufacturing defect which leads to a reduction of mechanical performance of the fibre reinforced polymer (FRP) composites. The current study investigates the effect of out-of-plane fibre waviness as a manufacturing defect on the flexural performance of carbon fibre reinforced polymer (CFRP) composites. Specimens with the non-uniform hump and non-uniform indentation waviness were fabricated using the transverse strip method. Experimental tests were conducted in the three-point flexural configuration using specimens with and without fibre waviness to investigate the flexural behaviour. Each of the above type of non-uniform waviness was investigated to evaluate the effect of the extent of the wave for three severity levels. Load-displacement response and digital optical microscopy were used to identify typical failure modes and damage initiation and progression in flexural specimens under test. Fibre kinking leading to delamination and fibre fracture were observed as prominent failure modes in hump as well as indentation waviness. Experimental investigation revels 12–30% reduction in flexural strength with increase in wave severity for the range considered in this study.

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