CAREER: Achieving Resilience in Brittle Materials Through Bio-inspired Nested Cylindrical Structures

陶瓷和脆性聚合物在生物医学、汽车和航空航天应用中发挥着关键作用。它们在经受热应力和机械应力时的灾难性失效是一个问题。相比之下，虽然海洋骨针也是由脆性陶瓷（二氧化硅）制成的，但由于其嵌套的圆柱形结构，它们显示出不寻常的韧性和灵活性。该学院早期职业发展（CAREER）奖将首先专注于研究在海洋海绵Euplectella aspergillum中发现的海洋骨针的微观结构，微观力学性能和裂纹发展模式和机制。研究结果随后将用于从刚性聚合物和陶瓷等脆性材料设计和制造类似的结构，并探索其在骨组织工程和其他应用中的潜力。作为该项目的一部分，研究将被纳入课程，以培养下一代工程师。本科生和研究生代表性不足的少数民族和女学生将被招募到研究工作。将为K-12学生提供暑期课程和研讨会，以了解增材制造。最后，高中教师将被邀请参加暑期研究项目，并通过合作研究加强产业联系。 本研究的目的是探讨建筑在脆性材料制成的仿生嵌套圆柱结构的断裂行为中的作用。灵感来自于由二氧化硅组成的海洋针状体，由于层状结构，它可以抵抗裂缝的传播。该计划是模仿和设计类似的结构，具有较低的重量和改进的断裂性能。首先，结合扫描电子显微镜和有限元建模将被用来广泛研究各种几何配置，粗糙度和表面的圆柱体和海洋骨针的材料特性的形态的增韧效果。这些发现将构成由坚韧聚合物和陶瓷制成的各种针状结构配置的基础，这些结构配置将通过立体光刻3D打印工艺制造。基于田口方法和有限元分析的广泛的实验程序将被用来了解操作变形机制。最后，将进行方差分析，以找到最影响断裂行为的关键参数。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Ceramics and brittle polymers play a pivotal role in biomedical, automotive, and aerospace applications. Their catastrophic failure when undergoing thermal and mechanical stresses is a concern. In contrast, although marine spicules are also made of a brittle ceramic (silica), they show unusual toughness and flexibility due to their nested cylindrical structure. This Faculty Early Career Development (CAREER) award will initially focus on investigating the microstructure, micromechanical properties, and crack development patterns and mechanisms in marine spicules found in a marine sponge, Euplectella aspergillum. The research findings will be subsequently used to design and fabricate similar structures from brittle materials such as rigid polymers and ceramics and explore their potential for bone tissue engineering and other applications. As part of the project, research will be integrated in the curriculum to train next-generation engineers. Undergraduate and graduate underrepresented minority and female students will be recruited into the research effort. There will be summer programs and workshops for K-12 students to learn about additive manufacturing. Lastly, high school teachers will be invited to summer research programs and industrial connections will be strengthened through collaborative research. The objective of this research is to investigate the role of architecture in the facture behavior of bio-inspired nested cylindrical structures made of brittle materials. The inspiration comes from marine spicules composed of silica that resist the propagation of cracks due to the layered structure. The plan is to mimic and engineer similar structures with lower weight and improved fracture performance. First, a combination of scanning electron microscopy and finite element modeling will be used to extensively examine the toughening effect of various geometrical configurations, roughness, and morphology of the surface of cylinders and materials properties of marine spicules. These findings will form the basis of various spicule-inspired structural configurations made of tough polymers and ceramics, which will be fabricated with stereolithography 3D printing processes. An extensive experimental program based on the Taguchi method and finite element analysis will be used to understand the operative deformation mechanisms. Lastly, the analysis of variance will be performed to find the critical parameters most affecting the fracture behavior.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.