Collaborative Research: Impact Resistant Equine Hoof - Structure, Properties and Bioinspired Designs

角蛋白是一种存在于大多数动物皮毛上的蛋白质，比如毛发、指甲、角、蹄、喙和羽毛。角质材料是最坚固的生物材料之一，它已经被大自然优化了其功能。例如，马蹄在重量轻的同时也能抵抗冲击。蹄子可以承受强大的动力，但产生这种特性的根本原因尚不清楚。这项研究将极大地促进对蹄子如何吸收能量的理解，并为建立新的抗冲击生物材料铺平道路。生物灵感设计包括利用自然的想法和合成材料来创造新的工程复合结构。抗冲击材料对于广泛的应用至关重要，包括身体保护（防弹衣背心和头盔），国防（防爆结构），汽车工业（抗碰撞车辆），航空航天（飞机鸟击）和空间探索（防止空间碎片）。这个跨学科的研究和教育项目涉及机械工程师、材料科学家和生物学家，包括角蛋白生物系统的实验和计算研究，以及在高速撞击中具有卓越能量吸收性能的新工程材料的设计和制造。参与的研究生将在学年期间与本科生研究人员配对，在夏季与高中生配对。计划纳入代表性不足的少数民族和女性学生。研究生将有在国家实验室接受训练和使用强大仪器的独特经历。本研究项目的目的是检验以下假设：1。蹄的分层结构有助于能量吸收和抵抗高速冲击。多尺度建模可以预测蹄的压缩和冲击行为；合成蹄形材料将具有出色的抗冲击性能。这项研究综合了不同领域（生物力学、材料科学与工程、生物学）的概念和方法。方法和途径包括角蛋白基材料的最先进的表征（小角度和广角x射线散射，纳米和微观计算机断层扫描，小角度中子散射，电子显微镜，纳米到宏观尺度的力学测试），新的本构模型的开发，以及基于蹄的特殊特性的抗冲击生物启发材料的设计，构建和测试。该项目的方法是变革性的，因为它结合了自然的想法（加速发现），利用计算材料科学方法（生成数据）筛选参数空间并创建结构-属性关系目录，并采用神经网络方法找到最佳设计。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。

Keratin is a protein found on the outer covering of most animals, such as hair, nails, horns, hooves, beaks, and feathers. Keratinous materials are among the most robust biological materials, which have been optimized by nature for their functions. For example, horse hooves are impact resistant while being lightweight. The hooves can withstand powerful and dynamic forces, but the fundamental reasons that give rise to this property are not known. This research will significantly advance understanding of how hooves absorb energy and pave the way to build new impact-resistant, bioinspired materials. Designs by bioinspiration involve using ideas from nature and employing synthetic materials to create new engineering composite structures. Impact resistant materials are essential for a wide range of applications, which include body protection (body armor vests and helmets), defense (blast resistant structures), automotive industry (crash-resistant vehicles), aerospace (aircraft bird strikes), and space exploration (protection against space debris). This transdisciplinary research and educational program involving mechanical engineers, materials scientists, and biologists, includes the experimental and computational studies of keratin-based biological systems and designs and fabrication of new engineering materials with a superb energy absorption performance during high-speed impacts. The participating graduate students will be paired with undergraduate researchers during the academic year and high school students during the summer. Inclusion of underrepresented minority and women students is planned. The graduate students will have the unique experience of getting trained and using powerful instruments at national laboratories. The objectives of this research project are to test the following hypotheses:1. The hierarchical structure of hooves assists in energy absorption and resists high-speed impacts, 2. Multiscale modeling can predict the compression and impact behaviors of hooves,3. Synthetic hoof-inspired materials will have outstanding impact resistant properties.This research integrates concepts and methods from diverse fields (biomechanics, materials science and engineering, and biology). The methods and approaches include the state-of-the-art characterization of keratin-based materials (small and wide angle X-ray scattering, nano-and micro-computed tomography, small angle neutron scattering, electron microscopy, nano- to macroscale mechanical testing), development of new constitutive models, and designing, building and testing of impact resistant bioinspired materials based on the exceptional properties of hooves. This project's approach is transformative as it incorporates ideas from nature (accelerates discovery), utilizes a computational materials science approach (generates data) to screen parameter space and create a catalog of structure-property relations, and employs neural network approach to find optimal designs.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.