Numerical Modelling of Scale-Dependent Damage and Failure of Composites

Abstract

A computational study of the size effects of open-hole tension composite laminates is carried out. The thickness-dependence of translaminar fracture toughness is accounted for in the numerical model, which enables the sublaminate-scaling effect of strength to be accurately predicted by a deterministic model. Neglecting delamination in modelling is found to cause mesh-dependence and over-estimation in strength predictions. A smeared crack model with cohesive elements between plies can reliably predict the failure mode, but not the strength, for laminates failed by delamination. A floating node method is developed for explicitly modelling multiple discontinuities within an element. The degree-of-freedom vectors do not have associated initial coordinates; they are assigned to new material points when needed during analysis. The proposed method is well suited for modelling strong, weak and cohesive discontinuities, for the representation of complex crack networks, and for the accurate modelling of matrix crack/delamination interactions in composites.