An Bingbing, Zhao Xinluo, Zhang Dongsheng
Department of Mechanics, Shanghai University, 99 Shangda Road, Shanghai 200444, PR China; Department of Physics, Shanghai University, Shanghai 200444, PR China.
Department of Physics, Shanghai University, Shanghai 200444, PR China.
J Mech Behav Biomed Mater. 2014 Jun;34:8-17. doi: 10.1016/j.jmbbm.2013.12.028. Epub 2014 Jan 29.
Biological materials exhibiting non-self-similar hierarchical structures possess desirable mechanical properties. Motivated by their penetration resistance and fracture toughness, the mechanical performance of model materials with non-self-similar hierarchical structures was explored and the distinct advantages were identified. A numerical model was developed, based on microscopic observation of enamel prisms. Computational simulations showed that the systems with non-self-similar hierarchy displayed lateral expansion when subjected to longitudinal tensile loading, which reflected negative Poisson׳s ratio and potential for greater volume strain energies when compared with conventional materials with positive Poisson׳s ratio. Employing the non-self-similar hierarchical design, the capability of resilience can be improved. Additionally, the non-self-similar hierarchical structure exhibited larger toughness, resulting from the large pull-out work of the reinforcements. The findings of this study not only elucidate the deformation mechanisms of biological materials with non-self-similar hierarchical structure, but also provide a new path for bio-inspired materials design.
具有非自相似层次结构的生物材料具有理想的力学性能。受其抗穿透性和断裂韧性的启发，对具有非自相似层次结构的模型材料的力学性能进行了探索，并确定了其明显优势。基于对牙釉质棱柱的微观观察，开发了一个数值模型。计算模拟表明，具有非自相似层次结构的系统在承受纵向拉伸载荷时会出现横向膨胀，这反映出与具有正泊松比的传统材料相比，其具有负泊松比以及更大体积应变能的潜力。采用非自相似层次设计，可以提高材料的回弹能力。此外，由于增强材料的拔出功较大，非自相似层次结构表现出更大的韧性。本研究的结果不仅阐明了具有非自相似层次结构的生物材料的变形机制，还为受生物启发的材料设计提供了一条新途径。
