Deformation and Failure of Mechanically Adaptive Cellular Materials

具有重要承载功能的人造结构需要费力且昂贵的设计工作，以确保安全和有效的性能。相比之下，在自然界中发现的承重结构会进化并成长为合适的结构，因为它们由自适应材料组成，如骨骼和木材，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是在网球运动员的重负荷球拍臂中观察到的更高的骨密度，宇航员由于低重力环境导致的骨量损失，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，骨和木材表现出优异的承载能力，重量轻，并且相对于合成材料，需要很少的资源来生产（即很少的能源和原材料）。该项目将评估一种生物启发的策略，用于制造适应其机械环境的合成材料。该策略将采用纳米制造技术，在多孔泡沫基材上存款结构坚固的纳米复合涂层。在适当的加工条件下，假设较厚的涂层可以沉积在经历较高负载的区域中，从而产生具有机械定制的微观结构的自适应纳米复合材料涂覆的泡沫。将进行一项测试计划，以确定这些材料的机械行为和性能，这将在建立均匀和自适应泡沫的加工、结构和性能之间的相互关系方面发挥不可或缺的作用。这些结果将能够评估纳米复合材料涂层泡沫的机械适应性，以及这些材料对预期工程应用的适用性。理论预测和初步结果表明，优异的机械性能（例如强度和刚度）与高孔隙率，低密度和多功能性的组合是可实现的，使这些材料成为生物医学应用中用作人工组织支架的优秀候选者，以及作为重量临界结构中的轻质承重材料。

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.