title: On flaw tolerance of nacre: a theoretical study.
abstract: As a natural composite, nacre has an elegant staggered 'brick-and-mortar' microstructure consisting of mineral platelets glued by organic macromolecules, which endows the material with superior mechanical properties to achieve its biological functions. In this paper, a microstructure-based crack-bridging model is employed to investigate how the strength of nacre is affected by pre-existing structural defects. Our analysis demonstrates that owing to its special microstructure and the toughening effect of platelets, nacre has a superior flaw-tolerance feature. The maximal crack size that does not evidently reduce the tensile strength of nacre is up to tens of micrometres, about three orders higher than that of pure aragonite. Through dimensional analysis, a non-dimensional parameter is proposed to quantify the flaw-tolerance ability of nacreous materials in a wide range of structural parameters. This study provides us some inspirations for optimal design of advanced biomimetic composites.
authors.affiliation: Department of Engineering Mechanics, Institute of Biomechanics and Medical Engineering, AML, Tsinghua University, , Beijing 100084, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Shao
authors.forename: Hong-Ping
authors.initials: HP
authors.lastname: Zhao
authors.forename: Xi-Qiao
authors.initials: XQ
authors.lastname: Feng
mesh_terms: D001696:Biomechanical Phenomena; D032701:Biomimetics / Q000379:methods; D008422:Materials Testing / Q000379:methods*; D008956:Models, Chemical; D060734:Nacre / Q000737:chemistry*; D033081:Shear Strength; D013718:Tensile Strength
chemical_list: D060734:Nacre
keywords: biomimetics; flaw tolerance; microstructure; nacre; strength