

Fracture Mechanics Model of Nacre
Abstract
In this paper, a linear elastic fracture mechanics framework is developed for investigating the toughening and strengthening mechanism observed in nacre. A half-infinite crack configuration is employed to obtain the toughening ratio. An equation governing the stress intensity factor is proposed and a general framework for solutions is established. The toughening ratio, the ultimate material strength and the flaw-tolerance of nacre and nacre-like composites are then investigated with the effects of platelet thickness and length, the composite stiffness and interfacial mechanical properties. The results demonstrate that the presence of platelet bridging in nacre is an important contribution to its high toughness, high strength and superior flaw-tolerance. In addition, it was shown that the aspect of platelets, nacre stiffness and interfacial strength in nacre significantly contribute to those outstanding mechanical properties mentioned above. These results provide detailed insights into the platelet bridging features that make nacre tough, stiff, strong and flaw-tolerant. Based on these results, some design guidelines for novel materials mimicking nacre have been also proposed.
Keywords
Nacre; Biological material; Microstructure; Toughening mechanisms; CrackText