DMREF: Designing Microstructure for Engineering Toughness

该项目汇集了一个跨学科团队，他们的愿景是开发数字制造方法，包括3D打印和喷墨打印，以合成具有特殊机械性能的结构材料。长期以来，人们一直认为材料的细微结构--微观结构--可以影响机械性能，这一点在材料加工和制造复合材料中都得到了利用。然而，这种努力历来局限于可以探索的微观结构的范围。这里的愿景是通过采用数字化和加法制造的方法来克服这一限制--这种方法出现了，并在很大程度上被用作原型制作工具--以制造具有优异机械性能的结构材料。研究人员特别关注骨折，因为它关系到生存工程的重要性，也因为它提出了深刻的科学问题。该项目将通过博士生和本科生在跨学科背景下的研究参与提供培训，并提供一个新的机会，让K-12学生参与进来，并在代表性不足的群体中促进STEM教育。在这个项目中，将寻求解决这一挑战的新的理论和计算方法。自由边界问题将使用变分破裂场方法正则化，裂纹扩展将在新的冲浪边界条件下进行研究。通过对轨迹进行参数优化和拓扑优化，实现微结构的优化设计。将探索创新的方法，使原型方法适用于具有设计微结构的结构材料的合成。虽然3D打印和塑料的相关方法已经得到了相当大的关注，但这些策略将在这里被用来合成合适尺寸的结构陶瓷。最后，新兴的实验方法，包括数字图像相关、X射线计算机断层扫描和共聚焦显微镜，将被用来提供对非均质材料中复杂的断裂过程的理论研究的洞察和验证。

This project brings together an interdisciplinary team with the vision of exploiting digital manufacturing methods, including 3D printing and ink-jet printing, to synthesize structural materials with exceptional mechanical properties. It has long been understood that the fine-scale structure of materials -- the microstructure -- can affect mechanical properties, and this has been exploited in both materials processing and in creating composite materials. However, such effort has historically been limited in the range of microstructures that could be explored. The vision here is to overcome this limitation by adapting methods of digital and additive manufacturing -- which emerged and have largely been used as tools for prototyping -- to make structural materials with superior mechanical performance. The investigators specifically focus on fracture because of its existential engineering importance and because it raises deep scientific questions. This project will provide for the training through research involvement of doctoral students as well as undergraduate researchers in an interdisciplinary setting, and a new opportunity for engaging K-12 students and for promoting STEM education amongst underrepresented groups.Fracture is a free discontinuity problem, and homogenization and optimal design of such problems is a long-standing intellectual challenge. In this project, new theoretical and computational approaches addressing this challenge will be pursued. The free boundary problem will be regularized using a variational fracture field approach, and crack propagation will be studied subject to a new surfing boundary condition. Optimal design of the microstructure will be pursued through parametric optimization and topology optimization applied to trajectories. Innovative approaches will be explored to adapt prototyping methods to the synthesis of structural materials with designed microstructures. While 3D printing and related methods for plastics have gained considerable attention, these strategies will be pursued here to synthesize structural ceramics at the appropriate size scales. Finally, emerging experimental methods, including digital image correlation, X-ray computed tomography, and confocal microscopy, will be employed to provide both insight into and validation of the theoretical studies of the complex process of fracture in heterogeneous materials.