Lattice simulations for evaluating interface fracture of masonry composites

• Obtaining brick–mortar interface fracture properties from basic strength properties.
• Determining the energy release rate of bi-material interfaces by lattice model.
• Obtaining the fracture energy values of cohesive zone models by the lattice model.
• Determining the toughness relation of bi-material interfaces by lattice model.

The brick–mortar bond is often the weakest link in the masonry composites. The localization of fracture processes at this bi-material interface plays an important role in the failure of this assemblage. These micro-level fracture processes control the nonlinear behavior of the brick–mortar interface which significantly affects the global behavior of the masonry structure in the continuum macro level. This study focuses on 2-D lattice-based fracture simulations to characterize progressive debonding of brick–mortar interfaces and to determine fracture properties in unreinforced masonry composites. Using the fundamental argument of Griffith which transforms potential energy into surface energy, lattice erosion is used to determine the critical energy release rate and other fracture quantities from basic strength properties of lattice struts that are removed upon failure. This micro-level information serves to upscale the lattice fracture arguments onto the meso-scale to quantify the fracture energy of traction-separation cohesive zone models in the context of continuum F.E. simulations of heterogeneous media like masonry.