Effect of projectile shape during ballistic perforation of VARTM carbon/epoxy composite panels

The use of carbon/epoxy composites in aircraft, marine, and automotive structural applications is steadily increasing. Robust composite structures processed using low-cost techniques with the purpose of sustaining high velocity impact loads from various threats are of great interest. An example of a low-cost process is the out-of-autoclave, vacuum assisted resin transfer molding (VARTM) technique. The present study evaluates the perforation and damage evolution created by various projectile geometries in VARTM processed carbon/epoxy laminates. A series of ballistic impact tests have been performed on satin weave carbon/epoxy laminates of 3.2 and 6.5 mm thickness, with projectile geometries representing hemispherical, conical, fragment simulating and flat tip. A gas-gun with a sabot stripper mechanism was employed to impact the samples with 50-caliber projectiles of the different shapes. The perforation mechanism, ballistic limit, and damage evolution of each laminate has been studied. The influence of projectile shape in the VARTM carbon/epoxy laminates under high velocity impact followed the analytical predictions by Wen [Compos. Struct. 49 (2000) 321; Compos. Sci. Technol. 61 (2001) 1163]. The conical shaped projectile resulted in highest ballistic limit, followed by the flat, hemispherical and the fragment simulating.