Improving the structural properties of composite T-joints by z-weaving of continuous metallic filaments

Abstract An experimental investigation is presented into improving the maximum load limit and other structural properties of T-shaped laminate joints by through-thickness weaving of thin metal filaments. Preforms of carbon fibre T-joints are first woven using continuous metallic or fibrous filaments made of copper, steel or carbon fibre yarns and then infused with epoxy. Stiffener pull-off tests performed on the cured T-joints show that the stainless steel z-filaments yield greater improvements to the strength and absorbed energy capacity than fibrous carbon fibre filaments by up to 80% and 30%, respectively, while copper filaments yield a smaller improvement than carbon fibre filaments. The levels of strengthening by the z-filaments depend on their volume fraction and material type, with stainless steel being more effective than copper or carbon. This study demonstrates that through-thickness weaving of continuous metallic filaments are highly effective at strengthening and toughening T-joints made of laminated composites.