The tensile and fatigue properties of carbon fiber-reinforced PEEK-titanium fiber-metal laminates

This paper investigates the tensile and fatigue properties of a novel fiber-metal laminate (FML) based on a titanium alloy and carbon fiber-reinforced poly-ether-ether-ketone (PEEK). Tensile tests on unidirectional unnotched laminates have shown that their mechanical properties follow the predictions offered by a simple law of mixtures approach. Tension-tension fatigue tests on notched unidirectional FMLs have shown that these laminates offer fatigue lives up to fifty times greater than those offered by a notched monolithic titanium alloy. An examination of the failed FMLs highlighted the presence of delamination between the titanium alloy and the fiber-reinforced composite. The experimental evidence suggests that this form of damage is harmful during fatigue loading conditions. It has also been shown that delamination is more widespread in FMLs based on thick composite layers than in laminates containing thin composite layers.