Date of Award

Spring 1-1-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Franck J. Vernerey

Second Advisor

Ronald Y. S. Pak

Third Advisor

Rong Long

Abstract

Balancing protection with mobility is a tradeoff all levels of the food chain have made in evolutionary development. The ability to withstand threats allows for longer life, as long as it does not degrade the ability to hunt and evade. The same can be said for modern engineered protection. Analogies can be drawn between common forms of man-made personal protection and the soft-body protecting structures seen in nature. However, nature has figured out how to balance encumberment with protection through the evolution of compound armors in a way that humans have yet to do in a relevant way. Fish-skin presents a novel protective structure that accomplishes this goal through the use of imbricated stiff scales embedded in soft dermal tissue. By modulating basic properties of the assembly, scale interactions can be enhanced to provide force dissipation and energy absorption. Here, the first three-dimensionally overlapping surrogate structures were fabricated and tested in quasi-static penetration loading. Layers of the fish-skin ultrastructure were analyzed for their role in protection. Scale surface morphology along with epidermal layers and mucus change the interactions between scales and the interaction with the threat. Increasing the number of scales involved in threat defeat increases the distribution of loading, and therefore, increases the survivability of the strike. Similarly, increasing the duration of scale engagement serves to increase the energy absorbed in defeat. Through evaluation of scale mechanics and response, direction can be provided for the flexible armor designs of the future.

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