Ballistic Limit of Thin CFRP Plates

JAXA (Japan Aerospace Exploration Agency) has carried out the hypervelocity impact tests for carbon fiber reinforced plastic (CFRP) plates together with CISAS (Centre of Studies and Activities for Space), University of Padova. Quasi-isotropic CFRP plates of 2.3, 3.5, and 4.7 mm in thickness were tested. Aluminum sphere of 0.8 to 2.9 mm in diameter was used as a projectile. The projectile was launched in a velocity range of 2 to 5 km/sec. The projectile impacted on the target in the normal direction. After the impact, peeling along the fiber direction was observed on the surface of the target. Moreover, delamination was generated near the surface of the target. A ballistic limit equation for CFRP was calculated by modifying the Cour-Palais equation. The ballistic limit equation for CFRP showed the good agreement with the test results.