Thickness effect on the mechanical properties of nacre in Hyriopsis cumingii under three-point bending

Abstract

To reveal the thickness dependence of nacre, the mechanical properties and microstructure of nacre with different thicknesses have been studied under three-point bending tests and SEM observations. The results show that the mechanical properties of nacre depend not only on the properties of the material itself, but also on the specimen thickness. The bending strength and fracture energy increase with decreasing specimen thickness, and the thinner specimens present better bending resistance than the thicker specimens. The mechanical properties of nacre have a significant thickness effect, and to characterize the variation of the thickness effect, the thickness effect sensitivity has been proposed. It is noteworthy that the difference in microscopic fracture modes of staggered “brick-bridge-mortar” structure is one of the factors affecting the thickness effect on the mechanical properties of nacre. Finally, the thickness effect on the bending strength is analyzed using the modified Weibull scaling law and Type-I scaling law, and the range of the thickness effect of nacre is indicated.