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

可持续经济的材料应该消耗很少的能源来生产，可持续的来源，容易回收或再利用。很少有材料既满足这些标准，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获得灵感，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）奖支持通过建筑材料中小规模断裂的新知识来创造坚固、坚韧和可持续材料的基础研究。生物衍生和/或可生物降解材料将使用先进的制造工具创建精确的微结构。小型和大型材料的力学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项目和课程，以促进下一代工程师可持续材料的使用。利用建筑来增强韧性的新兴策略通常具有生物灵感设计，但它们在很大程度上忽略了建筑如何影响断裂过程区的发展，特别是在小长度尺度上。在各向异性或分层结构中尤其如此，这些结构可能在多个长度尺度上发生复杂的破裂过程。这项研究将揭示当引入相关断裂长度尺度时，建筑如何抑制和重新分配材料尺度的损伤。采用宏观和纳米级增材制造，结构将使用可持续来源的材料，其特征等于或低于构成断裂过程区的尺寸。伴随的模拟将使用弹塑性损伤有限元模型来揭示不同结构如何扩散、偏转或阻碍损伤，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关于可持续材料设计的新的本科推广计划，该计划旨在招募代表性不足的社区大学生进入大学STEM项目。它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现有的工程问题。该奖项反映了美国国家科学基金会的法定使命，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.