Ballistic-performance optimization of a hybrid carbon-nanotube/E-glass reinforced poly-vinyl-ester-epoxy-matrix composite armor

The material model for a multi-walled carbon nanotube (MWCNT) reinforced poly-vinyl-ester-epoxy matrix composite material (carbon nanotube reinforced composite mats, in the following) developed in our recent work (M. Grujicic et al. submitted), has been used in the present work within a transient non-linear dynamics analysis to carry out design optimization of a hybrid polymer-matrix composite armor for the ballistic performance with respect to the impact by a fragment simulating projectile (FSP). The armor is constructed from E-glass continuous-fiber poly-vinyl-ester-epoxy matrix composite laminas interlaced with the carbon nanotube reinforced composite mats. Different designs of the hybrid armor are obtained by varying the location and the thickness of the carbon nanotube reinforced composite mats. The results obtained indicate that at a fixed thickness of the armor, both the position and the thickness of the carbon nanotube reinforced composite mats affect the ballistic performance of the armor. Specifically, it is found that the best performance of the armor is obtained when thicker carbon nanotube reinforced composite mats are placed near the front armor face, the face which is struck by the projectile. The results obtained are rationalized using an analysis of the elastic wave reflection and transmission behavior at the lamina/met and laminate/air interfaces.