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

角蛋白是一种蛋白质，存在于大多数动物的外壳上，如毛发、指甲、角、蹄、喙和羽毛。角蛋白材料是最坚固的生物材料之一，其功能已被自然界优化。例如，马蹄是耐冲击的，同时重量轻。蹄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。 这项研究将大大推进对蹄子如何吸收能量的理解，并为构建新的抗冲击生物材料铺平道路。生物灵感的设计涉及使用来自大自然的想法，并采用合成材料来创造新的工程复合结构。抗冲击材料在广泛的应用中必不可少，包括身体保护（防弹背心和头盔），防御（防爆结构），汽车工业（抗碰撞车辆），航空航天（飞机鸟撞）和太空探索（防止空间碎片）。 这个跨学科的研究和教育计划涉及机械工程师，材料科学家和生物学家，包括基于角蛋白的生物系统的实验和计算研究，以及在高速冲击过程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研究人员配对，并在夏季与高中生配对。计划招收代表性不足的少数民族学生和女学生。研究生将有在国家实验室接受培训和使用强大仪器的独特经验。本研究的主要目的是验证以下假设：1.蹄的层次结构有助于能量吸收和抵抗高速冲击，2。多尺度模型可以预测马蹄的压缩和冲击行为。以马蹄为灵感的合成材料将具有出色的抗冲击性能。这项研究整合了来自不同领域（生物力学、材料科学与工程以及生物学）的概念和方法。这些方法和途径包括角蛋白基材料的最新表征（小角和广角X射线散射、纳米和微米计算机断层扫描、小角中子散射、电子显微镜、纳米到宏观尺度机械测试）、新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。这个项目的方法是变革性的，因为它结合了大自然的想法（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-性质关系的目录，该奖项反映了NSF的法定使命，并通过利用基金会的智力价值进行评估，更广泛的影响审查标准。

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.