Computational study of the influence of microstructure on fracture behavior near crack-tip field in nacre-like materials

The small-scale failure process around a plane strain mode I crack in nacre -like materials is analyzed. The displacement increments of boundary nodes are specified by the analytical solutions based on the orthotropic linear elasticity to conduct an incremental finite element analysis. We set up a structural model composed of staggered arranged brittle aragonite tablets and cohesive zones within a process window surrounding the crack tip to investigate the toughness as well as the deformation mechanism in the fracture process zone. The results obtained by the parametric studies of different geometries and mechanical properties in the microstructure of the materials show that the aspect of failure in the near -tip fields can be categorized into four distinct fracture mechanisms. These mechanisms significantly affect the fracture toughness with differences of hundreds of times. We show a failure -mechanism map in which these fracture mechanisms can be divided into regions of geometry and mechanical properties in microstructure. Findings obtained in this study about the toughening mechanisms give us the useful knowledge to design novel materials with specific microstructures to control fracture mechanisms.