An Bingbing, Wang Raorao, Arola Dwayne, Zhang Dongsheng
Department of Physics, Shanghai University, Shanghai 200444, PR China; Department of Mechanics, Shanghai University, Shanghai, 200444, PR China.
The Tenth People׳s Hospital of Tongji University Shanghai, 200072, PR China.
J Mech Behav Biomed Mater. 2015 Feb;42:1-9. doi: 10.1016/j.jmbbm.2014.10.014. Epub 2014 Nov 4.
Enamel possesses a complex hierarchical structure, which bestows this tissue with unique mechanical properties. In this study, the mechanical behavior of single enamel rods was investigated under uniaxial compression. Numerical simulations were also performed using micromechanics models for individual enamel rods to identify the damage mechanisms contributing to the constitutive behavior. Experimental results showed that the single rods exhibited an elastic modulus ranging from 10~31 GPa, and that they undergo post-yield strain-hardening. The primary damage mode consisted of delamination within the assembly of mineral crystals. Results from numerical simulations suggest that strain localization within individual rods is responsible for the observed delamination, which is believed to arise from the non-uniform arrangement of mineral crystals. This mechanism was independent of mineral morphology and properties. The non-uniform crystal arrangement results in friction between crystals with different inclination angles and is believed to be responsible for the post-yield strain hardening behavior.
牙釉质具有复杂的层次结构，这种结构赋予了该组织独特的力学性能。在本研究中，对单个牙釉质棱柱体在单轴压缩下的力学行为进行了研究。还使用针对单个牙釉质棱柱体的微观力学模型进行了数值模拟，以确定导致本构行为的损伤机制。实验结果表明，单个棱柱体的弹性模量范围为10~31 GPa，并且它们在屈服后会发生应变硬化。主要损伤模式包括矿物晶体集合体内的分层。数值模拟结果表明，单个棱柱体内的应变局部化是观察到的分层的原因，据信这是由矿物晶体的不均匀排列引起的。这种机制与矿物形态和性质无关。晶体的不均匀排列导致不同倾斜角度的晶体之间产生摩擦，据信这是屈服后应变硬化行为的原因。
