CAREER: Creating Tough, Sustainable Materials Using Fracture Size-Effects and Architecture

可持续经济的材料应该只需要很少的能源来生产，可持续采购，并且易于回收或再利用。很少有材料能满足这些标准，同时又足够坚固和坚韧，可以在工程中广泛使用。为了解决这个问题，人们可以从天然材料中汲取灵感，通过使用精确的纳米和微观结构使其既可再生又耐用。该学院早期职业发展（CAREER）奖支持基础研究，通过建筑材料中小规模断裂的新知识创造坚固，坚韧和可持续的材料。生物衍生和/或生物降解材料将使用先进的制造工具制造出精确的微结构。对小型和大型材料的机械测试和计算机建模将揭示裂纹如何在复杂结构中生长和传播。这些知识将用于为航空航天，建筑和汽车行业设计新的可持续材料。它将进一步用于开发新的计划和课程，以促进下一代工程师使用可持续材料。新兴的战略，利用建筑，以提高韧性往往有生物启发的设计，但他们在很大程度上忽略了建筑如何影响骨折过程区的发展，特别是在小的长度尺度。在各向异性或分级结构中尤其如此，这些结构可能具有在多个长度尺度上发生的复杂断裂过程。这项研究将揭示如何架构可以抑制和重新分配材料规模的损害时，介绍了在相关的裂缝长度尺度。建筑将使用可持续来源的材料制成，其特征等于或低于使用宏观和纳米级增材制造的组成断裂过程区尺寸。伴随的模拟将使用弹塑性损伤有限元建模来揭示不同的结构如何扩展，偏转或阻止损伤，以创建更大的建筑断裂过程区并提高韧性。这些努力将被纳入一项新的关于可持续材料设计的本科生外展计划，该计划旨在招募代表性不足的社区大学生参加大学STEM课程。该奖项还将用于建筑材料设计的研究生课程，学生将尝试开发新的可持续材料解决方案，以解决现有的工程问题。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Materials for a sustainable economy should take little energy to produce, be sustainably sourced, and be easily recycled or reused. Few materials satisfy these criteria while also being strong and tough enough for broad use in engineering. To solve this, one can take inspiration from natural materials, which are made to be both renewable and durable by using precise nano- and microstructures. This Faculty Early Career Development (CAREER) award supports fundamental research for creating strong, tough, and sustainable materials through new knowledge of small-scale fracture in architected materials. Bio-derived and/or biodegradable materials will be created with precise microstructures using advanced manufacturing tools. Mechanical testing and computer modeling on both small- and large-scale materials will reveal how cracks grow and propagate in complex structures. This knowledge will be used to inform the design of new sustainable materials for aerospace, construction and automotive industries. It will further be used to develop new programs and courses for promoting sustainable materials use in the next generation of engineers. Emerging strategies using architecture to enhance toughness often have bioinspired designs, but they largely ignore how architecture affects the development of fracture process zones, especially at small length scales. This is especially true in anisotropic or hierarchical structures, which can have complex fracture processes occurring at multiple length scales. This research will reveal how architecture can inhibit and redistribute material-scale damage when introduced at relevant fracture length scales. Architectures will be made using sustainably sourced materials with features at or below the constituent fracture process zone size using both macro- and nanoscale additive manufacturing. Concomitant simulations will use elastic-plastic-damage finite element modeling to reveal how different structures can spread, deflect, or impede damage to create larger architectural fracture process zones and enhance toughness. These efforts will be incorporated into a new undergraduate outreach initiative on sustainable materials design that aims to recruit underrepresented community college students into university STEM programs. It will also be used in a graduate course on architected material design where students will try to develop new sustainable materials solutions to existing engineering problems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.