Fracture toughness analysis of interlocked brick and mortar structure considering the anisotropic behavior

The biological materials often display unique combinations of strength and toughness, which can provide an excellent prototype for designing advanced biomimetic materials. However, there still lacks a deep understanding in the relationship between geometric structure and material property. This paper established an crack-bridging model combining with the anisotropic stiffness properties, to reveal the crack-bridging toughening mechanism of interlocked brick and mortar structure. Then, the model is used to analysis the effect of geometric sizes, material parameters and interfacial properties to fracture toughness. Parametric studies demonstrates that the interlocking angle has a limited effect on fracture toughness. And increasing aspect ratio of platelets and elastic modulus ratio of stiff platelets and soft interface can greatly enhance the fracture resistance. In addition, the dissipating energy of the soft interface also has a positive contribution to the fracture toughness. This result potentially provides guideline to the design and optimization of novel biological materials with high strength and high ductility.