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.
