Cohesive modeling of transverse cracking in laminates under in-plane loading with a single layer of elements per ply

• We apply cohesive analysis to the classical case of transverse cracking in laminates.
• The in situ transverse strength is obtained accurately as output of the simulations.
• To obtain the same with a single element per ply the interface is made deformable.
• Analytical shear lag analysis is used to determine the interface stiffness.
• The approach is shown to work also for crack density predictions.

This study aims to bridge the gap between classical understanding of transverse cracking in cross-ply laminates and recent computational methods for the modeling of progressive laminate failure. Specifically, the study investigates under what conditions a finite element model with cohesive X-FEM cracks can reproduce the in situ effect for the ply strength. It is shown that it is possible to do so with a single element across the thickness of the ply, provided that the interface stiffness is properly selected. The optimal value for this interface stiffness is derived with an analytical shear lag model. It is also shown that, when the appropriate statistical variation of properties has been applied, models with a single element through the thickness of a ply can predict the density of transverse matrix cracks.