A numerical study on impact and compression after impact behaviour of variable angle tow laminates

Recent developments of variable angled tow (VAT) technology have indicated that variable stiffness composite laminates offer a strong potential for structural tailoring. However, the design complexity requires use of numerical analysis and novel techniques for this type of structural composites. This paper addresses the problem of the impact and compression after impact (CAI) behaviour prediction of variable stiffness composite laminates with emphasis on the effect of the interaction between fibre orientations, matrix-cracks and delaminations. An explicit finite element analysis using bilinear cohesive law-based interface elements and cohesive contacts is employed for the investigation. Examples are presented to illustrate the effectiveness of the current models for predicting the extent of impact damage and subsequent compression strength. The current study has improved the understanding of interactions between matrix-cracks and delaminations to clarify open questions on delamination initiation and how matrix cracks and fibre orientations interact.