Deformation and Failure of Mechanically Adaptive Cellular Materials

具有显著承载功能的人造结构需要费力且昂贵的设计工作，以确保安全和高效的性能。相比之下，自然界中的承重结构会进化并成长为合适的结构，因为它们是由骨和木材等适应性材料组成的，这些材料根据它们所承载的机械载荷进行自我配置。这种机械适应性的常见例子有网球运动员沉重的球拍手臂上观察到的较高的骨密度，宇航员由于低重力环境造成的骨量损失，或者反映环境压力的年轮厚度的变化。由于对外部环境的机械适应性，骨和木材表现出极好的承载能力，重量轻，与合成材料相比，生产所需的资源(即能源和原材料)很少。该项目将评估一种生物启发的策略，以制造适应其机械环境的合成材料。该战略将采用纳米制造技术，在多孔性泡沫衬底上沉积结构坚固的纳米复合涂层。在适当的工艺条件下，假设在承受较高载荷的区域可以沉积更厚的涂层，从而产生具有机械定制微结构的自适应纳米复合涂层泡沫。将进行一项测试计划，以确定这些材料的机械性能和性能，这将在建立均匀和自适应泡沫的工艺、结构和性能之间的相互关系方面发挥不可或缺的作用。这些结果将使评估纳米复合涂层泡沫的机械适应性，以及这些材料在预期工程应用中的适用性成为可能。理论预测和初步结果表明，高孔隙率、低密度和多功能的优异机械性能(例如强度和刚度)的组合是可以实现的，这使得这些材料成为生物医学应用中人工组织支架的极佳候选材料，以及作为重量关键结构中的轻型承载材料。

Man-made structures with a significant load-bearing function require laborious and costly design efforts in order to ensure safe and efficient performance. In contrast, load-bearing structures found in the natural world evolve and grow into suitable configurations because they are composed of adaptive materials, such as bone and wood, that self-configure according to the mechanical loads they carry. Familiar examples of this mechanical adaptability are the higher bone density observed in the heavily loaded racket-arm of tennis players, the loss of bone mass in astronauts due to a low gravity environment, or variation in annual tree ring thicknesses that reflect environmental stress. As a result of mechanical adaptability to the external environment, bone and wood exhibit excellent load-carrying capacity, are lightweight, and require little in the way of resources to produce (i.e. little energy and raw materials) relative to synthetic materials. This project will evaluate a bio-inspired strategy for fabricating synthetic materials that adapt to their mechanical environment. The strategy will employ a nano-fabrication technique to deposit a structurally robust nanocomposite coating onto a porous foam substrate. Under appropriate processing conditions, it is hypothesised that thicker coatings can be deposited in regions experiencing higher loading, resulting in adaptive nanocomposite-coated foams with mechanically tailored microstructures. A program of testing will be conducted in order to establish the mechanical behaviour and properties of these materials, which will play an integral role in establishing the interrelationship between the processing, structure, and properties of uniform and adaptive foams. The results will enable an assessment of the mechanical adaptability of nanocomposite-coated foams, and the suitability of these materials for anticipated engineering applications. Theoretical predictions and preliminary results suggest a combination of exceptional mechanical properties (e.g. strength and stiffness) with high porosity, low density, and multi-functionality is achievable, making these materials excellent candidates for use as artificial tissue scaffolds in biomedical applications, and as lightweight load-bearing materials in weight-critical structures.