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Publication Date

Fall 2013

Degree Type

Thesis - Campus Access Only

Degree Name

Master of Science (MS)

Department

Biomedical, Chemical & Materials Engineering

Advisor

Guna Selvaduray

Keywords

Armor, Biomimetics

Subject Areas

Materials Science

Abstract

Armor used for ballistic protection applications is driven by three main factors: protection level, system weight, and cost. Engineered ceramic armors are an attractive option over metallic systems because of the potential for weight reduction; however, large tiles of high-strength, monolithic ceramic are significantly more expensive than the metallic counterpart for an equivalent protection level. Ceramics also tend to fail catastrophically during impact, leading to secondary cracking and shrapnel, affecting the viability of the rest of the armor system and posing significant risks to personnel. Biological ceramic systems, such as those found in mollusks and crustaceans, incorporate relatively low-strength ceramics into complex structures. These assemblies reportedly exhibit greater damage tolerance over equivalent volumes of monolithic ceramics. Key microstructural elements of natural organo-ceramic systems were identified, adapted, and incorporated into a macro scale composite design. Two variants, one using a rigid adhesive and another with a flexible adhesive, were constructed and tested for flexure and impact. The flexible adhesive design reliably exhibited at least 10 times greater energy absorption over monolithic control samples and could be repeatedly struck in the same location at impact loads that caused catastrophic failure in the control samples. Secondary fractures were rarely observed in either design, and shrapnel generation was nearly zero in all cases. A cost/benefit analysis indicated a nearly 30% drop in material cost when compared to an equivalent volume of high strength silicon carbide.

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