Delamination is common in composite layered materials. These out-of-plane cracks are conventionally modelled through a layerwise strategy where each composite layer is represented with finite elements. The interface between layers is modelled with cohesive elements. This modelling strategy involves a fine discretisation through the thickness of the laminate. Additionally, cohesive elements need small in-plane elements (typically less than 1 mm) to accurately represent the interface fracture process zone. As a result, this conventional approach leads to prohibitive computational costs for large assemblies. The present work develops a strategy that is orders of magnitude more efficient for modelling delamination in large structures. The model initiates with a single solid-shell element representing the laminate thickness. The out-of-plane stresses are accurately recovered through the thickness of the laminate. The model is enriched with additional nodes at interfaces, where delamination is detected, to kinematically describe the cracks. Then, a novel energy-based cohesive method is used to model the crack propagation using large elements (e.g. 5 mm). The presented examples show that the novel modelling strategy is orders of magnitude faster than the conventional layerwise method while achieving comparable accuracy.
Abstract Delamination is common in composite layered materials. These out-of-plane cracks are conventionally modelled through a layerwise strategy where each composite layer is represented [...]
Efficient modelling of delamination for large structures 
