Statistical physics models for nacre fracture simulation

Natural biological materials such as nacre (or mother-of-pearl), exhibit phenomenal fracture strength and toughness properties despite the brittle nature of their constituents. For example, nacre's work of fracture is three orders of magnitude greater than that of a single crystal of its constituent mineral. This study investigates the fracture properties of nacre using a simple discrete lattice model based on continuous damage random thresholds fuse network. The discrete lattice topology of the proposed model is based on nacre's unique brick and mortar microarchitecture, and 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 that includes the mineral bridges between the aragonite platelets. The analysis indicates that the excellent fracture properties of nacre are a result of their unique microarchitecture, repeated unfolding of protein molecules (modular damage evolution) in the organic polymer, and the presence of fiber bundle of mineral bridges between the aragonite platelets. The numerical results obtained using this simple discrete lattice model are in excellent agreement with the previously obtained experimental results, such as nacre's stiffness, tensile strength, and work of fracture.