CAREER: Mechanics of Bio-inspired Multilayered Structures

这项教师早期职业发展项目旨在研究多层结构中韧性的尺寸尺度相关性。层状生物材料优异的力学性能与其层次化结构和性质有关--S有能力设计出具有纳米级结构元件的材料。该项目在生物材料的增韧机制和坚固结构复合材料的设计之间建立了联系。为了实现这一目标，将使用一种新的实验技术来研究生物和生物启发的多层膜的增韧机理，该技术可以在纳米尺度上实时测量裂纹的扩展。利用韧性起源的知识，冷冻铸造技术将被用来制造受自然启发的层状混杂复合材料。将建立力学模型，以了解生物和生物启发的多层材料中的粘弹性裂纹桥联、裂纹偏转和扭转等增韧机制。这些模型将用于优化受自然启发的复合材料的韧性，以及为广泛的结构应用设计定制的复合材料。教育计划对研究计划作出贡献并加以借鉴。该推广计划与非洲的一所大学合作，并与当地的一所社区学院合作。课程开发包括多学科工科课程的上岗团队教学。强度和韧性都是大多数结构材料的重要性能。尽管在开发更坚固更坚硬的材料方面已经取得了成功，但这些材料在没有适当的抗断裂性能的情况下，作为大块结构材料几乎没有用处。低估生物材料的力学行为是设计坚固结构材料的关键一步。本项目的目标是研究生物多层材料的韧性。这项基础性研究的实验技术和理论发现将对美国亟需的可持续基础设施的改善产生直接影响。所得模型可用于优化生物基复合材料的性能。教育倡议将通过与当地社区学院和公民学校的合作，让代表人数不足的群体参与。

This Faculty Early Career Development (CAREER) project aims to study the size-scale dependence of toughness in multilayered structures. The superior mechanical properties of layered biological materials relates to its hierarchical structure and nature?s ability to design these materials with nanoscale structural components. This project establishes a link between toughening mechanisms in biological materials and the design of robust structural composites. To achieve this goal, toughening mechanisms in biological and bio-inspired multilayers will be studied using a novel experimental technique that allows measurement of crack growth in real time at nanometer scale. Using the knowledge of the origin of toughness, a freeze-casting technique will be used to make nature-inspired layered hybrid composites. Mechanics models will be developed to understand the toughening mechanisms such as viscoelastic crack bridging, crack deflections and twisting in biological and bioinspired multilayered materials. The models will be used to optimize the toughness of nature-inspired composites as well as to design tailored composite materials for a wide range of structural applications. The educational plan contributes to and draws upon the research plan. The outreach program collaborates with a university in Africa and locally with a community college. The curriculum development includes inductive team-teaching of multidisciplinary engineering courses. Strength and toughness are both vital properties for most structural materials. Although there has been success in the development of stronger and harder materials, these materials have little to no use as bulk structural materials without appropriate fracture resistance. Understating the mechanical behavior of biological materials is a crucial step in the design of robust structural materials. The objective of this project is to study toughness in biological multilayer materials. The experimental techniques and theoretical findings from this fundamental research will have a direct impact on the improvement of much needed sustainable infrastructure in the United States. The resulting models can be used to optimize the properties of bio-based composite materials. The educational initiatives will involve participation of underrepresented groups through collaborations with local a community college and Citizen schools.