Collaborative Research: Mechanics of Structural Toughening in Sutured Composites

这项资助将研究缝合线几何形状如何影响复合材料性能的机制。生物盔甲和甲壳使用缝合关节，这种缝合关节是连接刚性材料域的波浪状、柔顺的夹层，这些缝合可以在几纳米到几毫米大小的长度范围内表现出来。一般认为，在复杂的载荷条件下，缝合接头可以增强生物复合材料的强度和韧性，但其潜在的机制尚不清楚。在必要长度尺度的材料结构的加工和表征方面的最新进展将使该项目能够提供缝合力学的第一个系统的实验研究和理论模型。这一新知识可以为新的添加剂制造范例提供基础，以提高印刷聚合物复合材料的性能。将开发教育和推广计划，吸引从幼儿园到研究生的学生，让他们接触机械和材料科学的概念。活动包括课程开发、本科生研究、外展课程和落基山力学研讨会。该项目的具体目标是在缝合线几何形状和复合材料破坏的三个关键阶段：裂纹形核、裂纹捕获和机械连锁之间建立结构-性能关系。本项目将寻求以下问题的答案：哪些结构缝合参数促进或抑制这三个阶段的每个阶段，以及如何平衡参数以放大复合材料的强度和韧性，并提高使用寿命？更具体地说，该项目的研究目标包括：(I)了解薄膜中的单线缝合机理；(Ii)了解薄膜中的缝线-缝合相互作用；(Iii)建立一个双波长添加剂制造平台，将薄膜中的知识外推到3D结构中，在那里可以研究存在弯曲、扭转和压缩载荷时的性能。为了实现这些目标，两阶段反应聚合物将被用来制造由不同波长、幅度、线宽和互锁角度的缝合线组成的复合材料；原子力显微镜将被用于快速作用力映射模式，以纳米分辨率表征缝合线性能的变化；有限元模型将被用来将缝合线几何形状与整体复合材料性能联系起来。研究结果将为层次化复合材料的结构增韧机制和断裂行为提供新的见解，并将导致单树脂、双波长3D复合材料打印方法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will investigate the mechanics of how suture geometry influences composite performance. Biological armors and carapaces employ suture joints, which are wavy, compliant interlayers that connect rigid material domains, and these sutures can manifest at length scales ranging from a few nanometers to millimeters in size. It is generally assumed that suture joints amplify the strength and toughness of biological composites in the presence of complex loading conditions, but the underlying mechanisms are not understood. Recent advancements in processing and characterization of material structure at requisite length scales will enable this project to provide the first systematic experimental investigation and theoretical modeling of suture mechanics. This new knowledge could provide the basis for a new additive manufacturing paradigm for printing polymer composites with improved performance. Education and outreach programs will be developed to engage kindergarten to graduate students, exposing them to engaging concepts in mechanics and materials science. Activities include course development, undergraduate student research, outreach lessons, and a Rocky Mountain Mechanics Symposium.The specific goal of the project is to establish structure-property relationships between suture geometry and three key stages of composite failure: crack nucleation, crack trapping, and mechanical interlocking. This project will seek answers to the questions such as: which structural suture parameters promote or inhibit each of the three stages, and how can parameters be balanced to amplify composite strength and toughness, and increase service life? More specifically, the research objectives of this project include: (i) understanding single-suture mechanics in thin films; (ii) understanding suture-suture interactions in thin films, (iii) establishing a two-wavelength additive manufacturing platform to extrapolate knowledge from thin films to 3D architectures where performance in the presence of bending, torsion, and compressive loadings can be studied. In pursuit of these objectives, two-stage reactive polymers will be employed to fabricate composites comprised of sutures with varying wavelength, amplitude, line width, and interlocking angles; atomic force microscopy will be used in fast force mapping mode to characterize variations in suture properties with nanometer resolution; finite element modeling will be leveraged to relate suture geometry to bulk composite performance. Results will offer new insights on structural toughening mechanisms and fracture behavior in hierarchical composites, and will lead to a single-resin, two-wavelength 3D composite printing methodology.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.