Experimental and numerical investigation on flexural performance of carbon fiber reinforced polymer composites with uniform and non‐uniform waviness

Abstract 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.