Fracture resistance design through biomimicry and topology optimization

Most biological composites including bones, teeth and nacres have superior fracture resistance properties than that of their constituents. Their complex mixing of stiff and soft constituents enables energy dissipation ahead of the crack tip and contributes to enhance the fracture performance. In this study, phase-field based modeling is used to understand the fracture resistance of bio-inspired designs. Phase-field based topology optimization is then proposed to further improve the fracture resistance of these composite structures. The fracture process from damage to multiple crack propagation and ultimately to failure is fully studied. Numerical experiments show that significant enhancement of the fracture toughness, failure strain and overall strength can be achieved over the homogeneous constitutive stiff material.