Toughness by Design

该基金的研究目标是了解和利用非均质性在创造独特的断裂特性中的作用。 虽然脆性断裂的研究已经有很长的历史，但对微观结构和整体韧性之间关系的理解还不完全。 最近的工作表明，有特殊的机会，大大影响韧性，利用定义明确的复杂的异质性。 具体而言，初步工作表明，精心设计的异质性可以显着提高整体韧性，并引入显着的不对称性，其中从左到右传播的裂纹前缘的阻力不同于从右到左传播的裂纹前缘的阻力。 与此同时，包括数字制造和自组装在内的新兴材料合成方法正在创造一种非凡的新能力，可以合成具有任意复杂但精确异质性的材料和组件。 拟议的研究将建立在此基础上，系统地研究一系列理想化但日益复杂的配置中的关键问题。 提出了一系列的理论，整体表征和先进的原位方法。 这些研究的结果将用于设计和合成复杂的微结构，使用快速成型。 如果成功的话，这笔赠款将使设计和合成的材料具有规定的韧性以及故障安全组件，其中裂纹-如果它发生-可以被钉在陷阱或偏转到区域，它造成最小的损害。 该项目将在高度协作的环境中培养一名博士生，该环境将理论，计算和实验相结合。 该项目还将为本科生创造研究机会，每年夏天。 在此提出的研究结果将积极纳入课程。

The research objective of this grant is to understand and exploit the role of heterogeneities in creating unique fracture properties. While the study of brittle fracture has a long history, an understanding of the relation between microstructure and overall toughness is incomplete. Recent work has shown that there are exceptional opportunities to dramatically affect toughness by exploiting well-defined complex heterogeneities. Specifically, preliminary work suggests that well-designed heterogeneities can dramatically enhance the overall toughness, and introduce a significant asymmetry where the resistance of a crack front propagating from left to right is different from that of a crack front propagating from right to left. Simultaneously, emerging methods of materials synthesis including digital manufacturing and self-assembly are creating an extraordinary new ability to synthesize materials and components with arbitrarily complex but precise heterogeneities. The proposed research will build on this by systematically examining critical issues in a series of idealized but increasingly complex configurations. A range of theoretical, overall characterization and advanced in-situ methods are proposed. The results of these studies will be used to design and synthesize complex microstructures using rapid prototyping. If successful, the grant will enable the design and synthesis of materials with prescribed toughness as well as fail-safe components where a crack -- if it were to occur -- could either be pinned in traps or be deflected into regions where it causes minimal damage. This project will train a doctoral student in a highly collaborative setting that combines theory, computation and experiment. This project will also create research opportunity for an undergraduate student each summer. The results of the research proposed here will be actively incorporated into the curriculum.