CAREER: Biomechanics of Amphibious Fish Fins and Mechanical Principles of Stiff Lightweight Structures

该学院早期职业发展（CAREER）资助将使用工程来发现允许两栖鱼在陆地上移动的生物力学专业。 这是科学的兴趣，因为这些鱼使用他们的薄和重量轻的鳍施加非常大的力量在陆地上移动。通过生物实验，工程设备设计和数学建模，该项目旨在揭示用于在陆地上移动的鳍的形式和功能之间的关系。 在这个项目中获得的知识将影响几个领域。了解步行鱼的力学将有助于解决设计能够穿越不同环境的敏捷机器人的重大挑战。这对于未来使用这种机器人进行搜索和救援行动以及远程生态研究非常重要，以便前往人类无法前往或不安全的地方。 了解两栖鱼类对于了解陆生脊椎动物如何从大约4亿年前使用鳍在陆地上移动的水生祖先进化而来也至关重要。该项目的协同教育和外展活动包括课程开发、高中生多年支架式导师计划以及学生开发的两栖鱼类动手博物馆展览，这些展览也将作为学校教师的新型教具。这些项目旨在扩大从K-12到大学的STEM参与，并培养下一代跨学科科学家。该跨学科研究的目标是发现弹涂鱼这种两栖鱼类如何专门化其鳍设计和生物力学，以承受在陆地上移动的力，并验证它们利用曲率诱导刚度的非线性效应抵抗地面力的假设。曲率引起的刚度原理有助于人类的脚承受地面力，水生鱼类的鳍也表现出这种效果所需的元素。但是鳍和脚的解剖学表现是完全不同的，这就提出了一个问题，即两栖鱼是如何在陆地上长鳍的。该项目将联合收割机实验与理论相结合，从整个生物体（~10 -100毫米）到鳍的内部结构（~ 10 - 100微米），研究两栖（弹涂鱼和bichirs）和水生鱼类（虾虎鱼和鲭鱼）鳍的多尺度、层次和复合结构。具体的目标，对运动生物力学和鱼鳍结构力学的根本影响，是（i）使用新型光学力传感器测量弹涂鱼鳍上的体内力，（ii）使用两栖和水生鱼鳍上的体外机械测试识别关键刚度贡献解剖元素，（iii）结合3D微计算机断层扫描（microCT），发现两栖鱼类鳍的特化，推导鳍形态功能空间的可推广的生物力学原理，体内力和体外刚度数据与多尺度，复合弹性手指模型。鳍的形状与功能关系的发现对于生物学家研究鳍和四肢的发育和进化至关重要。此外，新颖的附件设计可能会大大提高多地形机器人的有效性。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。

This Faculty Early Career Development (CAREER) grant will use engineering to discover the biomechanical specializations that allow amphibious fish to move on land. This is of scientific interest because these fish use their thin and lightweight fins to apply very large forces to move on land. Through biological experiments, engineering device design, and mathematical modeling, the project seeks to uncover relationships between the form and function of fins used to move on land. The knowledge gained in this project will impact several fields. Understanding the mechanics of walking fish will help address the substantial challenges in designing agile robots capable of traversing diverse environments. This is important for future use of such robots for search and rescue operations and remote ecological studies to go where it is impossible or unsafe for humans to go. Learning about amphibious fish is also critical for understanding how terrestrial vertebrates evolved from an aquatic ancestor that used its fins to move on land around 400 million years ago. The project’s synergistic education and outreach activities include curriculum development, a multi-year scaffolded mentorship plan for high school students, and student-developed hands-on museum exhibits on amphibious fish that will also serve as novel teaching aids for school teachers. These will be designed to broaden participation in STEM from K-12 through college and incubate the next generation of interdisciplinary scientists.This interdisciplinary research objective is to discover how the mudskipper, an amphibious fish, has specialized its fin design and biomechanics to withstand forces for moving on land and test the hypothesis that they resist ground forces using the nonlinear effect of curvature-induced stiffness. The curvature-induced stiffness principle helps human feet withstand ground forces, and aquatic fish fins also manifest elements needed for that effect. But the anatomical manifestations are quite different in fins and feet, raising the question of how amphibious fish stiffen their fins on land. The project will combine experiments with theory to investigate the multi-scale, hierarchical, and composite structure of the fins of amphibious (mudskippers and bichirs) and aquatic fish (gobies and mackerels) from the whole organism (~10–100 millimeters) down to the fin’s internal structure (~10–100 micrometers). The specific aims, with fundamental impact on locomotion biomechanics and fish fin structural mechanics, are to (i) measure in vivo forces on mudskipper fins using a novel optical force sensor, (ii) identify critical stiffness-contributing anatomical elements using in vitro mechanical tests on amphibious and aquatic fish fins, and (iii) discover the specializations of amphibious fish fins and derive generalizable biomechanical principles of a fin morpho-functional space by combining 3D micro-computed tomography (microCT), in vivo force, and in vitro stiffness data with multi-scale, composite-elastic fin models. Discoveries on the fin’s form-function relationships could be crucial for biologists studying the development and evolution of fins and limbs. Also, novel appendage designs may considerably enhance the effectiveness of multi-terrain robots.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.