Hard biological materials and novel bio-inspired composites

数十亿年的进化产生了极其高效的天然材料，这些材料正日益成为工程师们的灵感来源。在材料科学中，仿生学（模仿自然的科学）现在开始激发具有非凡机械性能的新型材料。本研究的重点是硬生物组织（贝壳、牙齿）的机械性能，以及新型“仿生”结构和材料的开发。例如，在许多种类的贝壳中发现的珍珠，比制造它的易碎陶瓷（文石）坚硬3000倍。这种程度的改进是目前人造复合材料无法比拟的，但大自然证明这是可能的。牙釉质和牙本质是另一种坚固的材料，可以承受多年的强烈机械和热负荷。本研究的目的是了解这些材料的微观结构如何控制其机械性能。我们使用实验和计算机模拟来研究宏观尺度、微观尺度和纳米尺度（一米的十亿分之一）的机制。更具体地说，我们的研究集中在：(1)珍珠壳和牙齿的变形和断裂，重点关注阻止裂纹扩展的微观机制；（ii）控制矿物包裹体之间界面行为的纳米级力学；（iii）这些材料如何作为结构系统（例如：牙釉质和牙本质）；（iv）建立设计规则，使关键机制能够复制到人工材料中。在长期目标的背景下，我们将制造新型仿生材料：用于演示关键概念的大型模型材料，用于航空航天和装甲系统的高性能复合材料，或具有增强附着力的陶瓷涂层。

Billions of years of evolution have produced extremely efficient natural materials, which are increasingly becoming a source of inspiration for engineers. In materials science, biomimetics (the science of imitating nature) is now starting to inspire novel materials with extraordinary mechanical properties. This research focuses on the mechanical performance of hard biological tissues (seashells, teeth), and on the development of novel "bio-inspired" structures and materials. For example nacre, found inside many species of seashells, is 3000 times tougher than the fragile ceramic of which it is made (aragonite). This degree of improvement is currently not matched by man-made composite materials, but nature demonstrates that it is possible. Tooth enamel and dentin are other examples of tough materials combined to withstand intense mechanical and thermal loading over many years. The goal of this research is to understand how the microstructure of these materials controls their mechanical performance. We use experiments and computer simulations to study mechanisms at the macroscale, at the microscale and at the nanoscale (one billionth of a meter). More specifically, our investigations focus on: (i) the deformation and fracture of nacreous shells and teeth, focusing on the micromechanisms which prevent cracks from propagating; (ii) the nanoscale mechanics that control the behavior of the interfaces between the mineral inclusions; (iii) how these materials perform as structural systems (for example: enamel and dentin in tooth); and (iv) establishing design rules enabling the duplication of key mechanisms into artificial materials. In the context of long-term objectives, we will fabricate novel bio-inspired materials: large scale model materials to demonstrate key concepts, high performance composites for aerospace and armor systems, or ceramic coatings with enhanced adhesion.