A biomimetic example of brittle toughening .1. Steady state multiple cracking

Multiple cracking dissipates energy and thus enhances the toughness of materials and structures composed of relatively brittle constituents. In this paper a biomimetic example is studied, i.e. the fracture behavior of the conch shell (Strombus Gigas). We focus on multiple cracking which occurs in the macroscopic layer on the tensile side of 4-point bend specimens with the crossed-lamellar microstructure. The interaction between the cracks results in mutual shielding and thus a lower stress intensity factor at each crack tip. An approximate fracture mechanics model of this mechanism is presented.