Abstract
Dental enamel possesses extraordinary mechanical properties due to a complex hierarchical and graded microstructure. In this study, multiscale experimental and computational approaches are employed and combined to study nature’s design principle of the hierarchical structure of bovine enamel for developing bio-inspired advanced ceramics with hierarchical microstructure. Micro-cantilever beam tests are carried out to characterize the mechanical properties from nano- to meso-scale experimentally. In order to understand the relationship between the hierarchical structure and the flaw-tolerance behavior of enamel, a 3D representative volume element (RVE) is used in a numerical analysis to study the deformation and damage process at two hierarchical levels. A continuum damage mechanics model coupled to hyperelasticity is developed for modeling the initiation and evolution of damage in the mineral fibers as well as protein matrix. Moreover, debonding of the interface between mineral fiber and protein is captured by a cohesive zone model. The effect of an initial flaw on the overall mechanical properties is analyzed at different hierarchical levels to understand the superior damage tolerance of dental enamel. Based on the experimental and computational investigation, the role of hierarchical levels on the multiscale design of structure in dental enamel is revealed for optimizing bio-inspired composites.
DOI Link to Publication