Low-Velocity Impact Damage on Thick-Section Graphite/Epoxy Laminated Plates

The differences and similarities between thin and thick composite lami nated plate responses to impact were experimentally investigated. The impact resistance of graphite/epoxy specimens of thickness varying from 0.254 to 2.54 cm were studied. All tests were conducted at low velocities in a drop tower apparatus. Ultrasonic C-scans of the damaged specimens were used to quantify the impact damage. Cross sections of some im pacted specimens were also examined to determine the through-the-thickness damage. Re sidual flexural strength was measured with a three-point flexural test fixture. The results show that the thin/thick laminate impact behavior transition occurs at a thickness situated between 0.635 and 1.37 cm.