Delamination fatigue resistant three-dimensional textile self-healing composites

Abstract

This paper presents a novel three-dimensional (3D) hybrid textile composite that uniquely combines high resistance to mode I and mode II interlaminar fatigue cracking with the capacity to in-situ repair fatigue-induced delamination cracks. The 3D hybrid textile composite contains two types of through-thickness z-binder reinforcements made of carbon fibre tows (which provide high resistance to interlaminar fatigue cracking) and thermoplastic filaments (which provide the capability to heal fatigue cracks). The fatigue resistance of this 3D hybrid composite is compared with 3D textile composites containing only one of the two z-binders. Compared to the unmodified laminate, the hybrid z-binder reinforcements increase the mode I and mode II interlaminar fatigue resistance by ~800% and ~200%, respectively, while simultaneously providing the in-situ healing of fatigue-induced cracks. The improvement to the fatigue crack growth resistance of the 3D hybrid textile composite is much greater under mode I compared to mode II interlaminar cyclic loading. Quantitative models of the fatigue crack growth rates are presented together with fatigue strengthening and healing mechanisms of the 3D hybrid textile composite.