Effect of Projectile Type, Size and Impact Velocity on Ballistic Impact Failure Behavior of TROGAMID CX-7323 Nylon

摘要

Extensive study on the fracture behavior of TROGAMID CX-7323 (CX- 7323) nylon under ballistic impact was performed. Generally, CX-7323 exhibits ductile failure upon impact with a 17-grain fragment simulating projectile(s) (FSP). Penetration is initiated by ductile shearing upon impact. Subsequent tensile stretching allows the penetration event to progress. Material in front of the projectile is pushed out of the way during penetration. Significant elastic recovery of the exit hole is noticed after complete penetration. Upon impact of a right circular cylinder(s) (RCC) the failure behavior was mixed depending on the size of the fragment. With smaller RCC (2-grain, 4-grain) the failure is similarly ductile as when impacted with FSP. Larger RCC (16-, 17- and 64-grain) at impact velocities above the ballistic limit frequently cause a different failure mode in CX- 7323 nylon. Initial penetration is marked by ductile shearing with a hole similar in size to the projectile. Upon complete penetration, brittle, conoid spallation occurs. Annealing negatively affected notched Izod impact results, but ballistic performance was maintained past temperatures significantly higher than the Glass Transition (Tg) of CX-7323.