A continuous damage random thresholds model for simulating the fracture behavior of nacre

This study investigates the fracture properties of nacre using a discrete lattice model based on continuous damage random threshold fuse network. The discrete lattice topology of the model is based on nacreʹs unique brick and mortar microarchitecture. The mechanical behavior of each of the bonds in the discrete lattice model is governed by the characteristic modular damage evolution of the organic matrix and the mineral bridges between the aragonite platelets. The numerical results obtained using this simple discrete lattice model are in very good agreement with the previously obtained experimental results, such as nacreʹs stiffness, tensile strength, and work of fracture. The analysis indicates that nacreʹs superior toughness is a direct consequence of ductility (maximum shear strain) of the organic matrix in terms of repeated unfolding of protein molecules, and its fracture strength is a result of its ordered brick and mortar architecture with significant overlap of the platelets, and shear strength of the organic matrix.