Interface Engineering of Fiber Reinforced Calcium-based Composites

不连续和随机取向的纳米/微纤维(钢、碳、聚合物)作为钙基材料的增强材料在民用和生物医学应用中的应用越来越受到关注，因为它们在优异的结构和多功能复合材料方面具有广阔的前景。纤维和基质之间的界面对材料性能起着至关重要的作用，必须准确地表征它才能有效地设计材料。本研究项目的目的是了解纤维增强钙基复合材料的增强机理。对纤维增强材料关键特性的基本了解将有助于更好的材料设计和制造策略。更广泛的影响是双重的。土木工程应用：先进材料延长土木工程基础设施的寿命，降低维护成本，增强安全性和可持续性，每年将节省数十亿美元的税收，并对社会产生许多放大的间接影响。生物医学应用：先进的仿生材料将提供更有效的医疗。教育部分将向高中生介绍这门有趣的微小科学，并将开发一门研究生水平的材料耐久性课程模块。目标是从根本上了解控制纤维增强钙基材料增强机制的纤维-固体-液体界面的分子结构和动力学，重点是确定界面的性质及其与界面力学行为的关系。重点放在分子到纳米尺度和增强基质界面的化学-机械相互作用上。分子动力学建模和界面结构和动力学的实验表征将被用来(I)阐明纤维表面、含钙固相和周围液相之间的界面相互作用，(Ii)量化和关联化学结构对增强体界面的力学性能的影响，以及(Iii)建立连接分子尺度和界面微观连续尺度的分子动力学信息的界面内聚力-分离关系。这项研究将(I)提供实现改善工程性能所需的分子到纳米尺度的图像，(Ii)在界面上的化学和机械性能方面取得进展，以及(Iii)在界面上弥合纳米力学和微观力学之间的差距。

The use of discontinuous and randomly oriented nano/microfibers (steel, carbon, polymer) as reinforcements in calcium-based materials for civil and biomedical applications has received increasing attention due to their promising potential for superior structural and multifunctional composites. The interface between the fibers and the matrix plays a vital role in material performance and must be accurately characterized to effectively design materials. The goal of this research project is to understand reinforcement mechanisms in fiber reinforced calcium-based composites. Fundamental understanding of key features of fiber reinforcements will enable better material design and fabrication strategies. The broader impacts are twofold. Civil engineering applications: Advanced materials that extend the life of civil infrastructure, reduce maintenance costs, and enhance safety and sustainability will save billions of tax dollars a year and have many magnified indirect effects on society. Biomedical applications: Advanced biomimetic materials will provide more effective medical treatments. The educational component will introduce high school students to the intriguing science of the very small and will develop a graduate level course module on material durability.The goal is to fundamentally understand the molecular structure and dynamics at the fiber-solid-liquid interfaces that control reinforcement mechanisms in fiber reinforced calcium-based materials with an emphasis on determining the nature of the interface and how it relates to interfacial mechanical behavior. The focus is on the molecular to nanoscale and the chemo-mechanical interactions at reinforcement matrix interfaces. Molecular dynamics modeling and experimental characterizations of the structure and dynamics of the interfaces will be integrated to (i) elucidate the interfacial interactions between fiber surfaces, calcium-bearing solid phases, and surrounding liquid phases, (ii) quantify and relate the effect of the chemical structure to the mechanical properties of reinforcement matrix interfaces, and (iii) formulate molecular dynamics-informed interface cohesive traction-separation relationships that connect the molecular scale to the micro-continuum scale at interfaces. The research will (i) provide a molecular to nanoscale picture necessary to achieve improved engineering properties, (ii) make advances in relating chemistry and mechanical properties at interfaces, and (iii) bridge the gap between nano-mechanics and micro-mechanics at interfaces.