A three-dimensional fracture pattern diagram of staggered platelet structures

In order to design composites that mimic the remarkable balance of properties such as strength, toughness, and stiffness of staggered platelet structures in nature, it is crucial to understand their load transfer and failure mechanisms. Recently, we proposed an analytical model to predict the stress distribution within staggered platelet structures for a wide range of constituent materials' moduli and geometric parameters in the elastic response regime. Here, based on the model, a fracture pattern diagram featuring three distinct mechanisms categorized according to the failure sequences of soft tip, soft shear zone, and hard platelet is constructed. The proposed fracture map is capable of capturing the transition of failure mechanisms observed in crack phase field simulations and draws parallels to mechanisms seen in experiments. Our study sheds light on the origin of failure mechanism transitions and enables rational designs of future staggered platelet composites with unprecedented properties.