Tensile and Flexural Damage Response of Symmetric Angle-Ply Carbon Fiber-Reinforced Epoxy Laminates: Non-Linear Response and Effects of Thickness and Ply-Stacking Sequence

Advanced fiber reinforced composites have excellent specific strength and stiffness properties, but tend to be limited by linear elastic response and sudden, brittle failure. This lack of ductility greatly limits the structural efficiency of reinforced composite designs. Hence, achieving some non-linear behavior is desirable and it can help composite structures to maintain functionality even when they are overloaded to improve safety and reduce the applied safety factors. The aim of this study is to characterize and assess the effect of laminate thickness and the type of scaling technique on the damage response of symmetric angle-ply carbon fiber-reinforced polymer (CFRP) composite laminates subjected to tensile and flexural loading. This study considers the different behavior of the composite material under tension and compression in order to evaluate their influence on the failure modes. Tensile and three-point bending tests were carried out to determine the mechanical response in terms of strength and stiffness of the different CFRP laminates. Optical micrographs of failed samples were used to assess damage mechanisms of the different configurations. It was observed that non-linear behavior and high strains to failure could be achieved with angle-ply laminates. Furthermore, the maximum flexural strength increased and maximum flexural strain decreased as laminate thickness increased. Finally, the results obtained demonstrate that introducing ply clustering had a negative effect on the mechanical performance and pseudo-ductility exhibited by angle-ply laminates. POLYM. COMPOS., 40:3678-3690, 2019. (c) 2019 Society of Plastics Engineers