Region-dependent micro damage of enamel under indentation

• Published in: Acta mechanica Sinica 2012-12, Vol.28 (6), p.1651-1658
• Main Authors: An, Bing-Bing, Wang, Rao-Rao, Zhang, Dong-Sheng
• Format: Article
• Language: English
• Subjects: Chains; Classical and Continuum Physics; Computational Intelligence; Computer simulation; Damage; Density; Enamels; Engineering; Engineering Fluid Dynamics; Mathematical models; Proteins; Research Paper; Stiffness; Theoretical and Applied Mechanics; 加载曲线; 实验数据; 微损伤; 数值模拟; 模拟负载; 牙釉质; 破坏行为; 蛋白质链
• ISSN: 0567-7718; 1614-3116
• DOI: 10.1007/s10409-012-0203-7

The objective of this investigation is to explore the region-dependent damage behavior of enamel, as well as to develop a good understanding of the deformation mech- anisms of enamel with numerical modeling. Nanoinden- tation experiments have been performed to investigate the load-penetration depth responses for outer and inner enamel. Results show that the unloading curve does not follow the loading curve, and degradation of stiffness in the unloading curve is observed. Based on the experimental data, a physi- cal quantity, the chain density in protein, has been introduced to the Drucker-Prager plastic model. Numerical simulations show that the simulated load-penetration depth curves agree with the experiments, and the stiffness degradation behav- iors of outer and inner enamel are captured by the numerical model. The region-dependent damage behavior of enamel could be revealed by the numerical model. The micro dam- age affected area at inner enamel is larger than that at outer enamel, indicating that the inner enamel experiences more micro damage than the outer one. Compared with its outer counterpart, the inner enamel which is rich in organic protein could break more internal protein chains to dissipate energy and to enhance its resistance to fracture accordingly.