Crack behavior in nacre-like composites: A phase-field method
Journal
Proceedings of SPIE - The International Society for Optical Engineering
Journal Volume
11586
Date Issued
2021
Author(s)
Abstract
Many biological materials such as bone, teeth and nacre exhibit superior mechanical strength and toughness. These materials share similar hierarchical arrangement that stiff blocks are embedded in a soft matrix. For example, the sophisticated brick-and-mortar design in nacres can effectively increase the fracture toughness by a factor of 3,000 compared to its major component - mineral. Although extensive studies have been done attempting to understand the toughening of the nacre-like materials, the underlying mechanisms associated with crack behaviors are not fully clear yet. This study applies the phase-field method for crack behaviors in both layered structure and nacre-like materials to distinguish the importance of the commonly observed toughening mechanisms. First, we investigate the toughening of a simple layered structure, where the surfing boundary condition is imposed to suppress the crack deflection. We compute the maximum energy release rate using the J-integral technique to find out that the effective fracture toughness is much less than the experimentally measured fracture toughness of these bio- composite materials. Then we investigate the crack growth in a nacre-like material to obtain a phase diagram summarizing four different modes of crack growth: straight crack, interface crack, branching, and crack arrest for a range of structural parameters relevant to nacres, including the aspect ratio, volume fraction of mineral, elastic modulus mismatch and fracture resistance mismatch. Our results clarify the relation between the complex hierarchical microstructure and the toughening mechanisms, such as crack bridging, microcracking and tablet sliding. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
Subjects
Crack behavior
Nacre-like Materials
Phase-Field Method
Toughening
Aspect ratio
Biological materials
Biomimetics
Crack propagation
Cracks
Gems
Phase transitions
Biocomposite materials
Effective fracture toughness
Elastic modulus mismatch
Hierarchical microstructures
Maximum energy release rate
Strength and toughness
Structural parameter
Toughening mechanisms
Fracture toughness
SDGs
Type
conference paper