Metallic glass honeycombs and composite body armo

Honeycombs are light weight cellular structures that carry the normal and shear loads in the surfaces perpendicular to the axis of honeycomb cells. The work presented in this thesis explores new metallic glass honeycombs. A "bottom-up" manufacturing method was formulated and devised using which honeycombs were made from amorphous Fe-Ni based ribbons having high yield strength. The 97% porosity honeycomb prototypes were manufactured with each cell in the shape of a "teardrop". The prototypes were found to have a collapse stress of 4.6 GPa in the out-of-plane (X3) direction. Defects reduced the ultimate performance; however the specific strength remained high. A hybrid composite plate insert was fabricated using amorphous honeycombs as a energy absorptive stratum to make a high-powered rifle resistant body Armor with Dyneema HB50 (UHMWPE) as the facing layer. The plate inserts were subjected to ballistic testing in accordance to the standards of the National Institute of Justice (NIJ) against Level III NATO M80 bullet threats. The ballistic results when compared to the baseline configuration at 15 kg/m2 indicate a reduction in the Back Face Signature by 27% for an increase of 13% in areal density by addition of the energy absorptive honeycomb layer. The V50 of the prototype composite Armor panel was also found to be 865+/-10 m/s for the Level III threat with several areas of improvement identified.