Effects of Impact Conditions and Stacking Sequence on Impact Damage in CF/PEEK Laminates

The flat-wise hard and soft body impact resistance of two kinds of carbon fiber/PEEK systems were evaluated using drop weight (mass=2.5 kg, 1 to 3 m/s), aluminum bullet (mass=1.9 g, 50 to 100 m/s), and gelatin projectile (mass=3 g, 90 to 190 m/s) impact tests. Tested systems were AS4/PEEK (APC-2/AS4) and AS4/PEEK+IL, which consist of APC 2 prepreg and PEEK film inserted between layers as an interleave. For investigation of the effects of the stacking sequence on resistance, the fiber angle and lamina thickness were varied as experimental parameters. The projected damage area was measured using an ultrasonic C Scan. The impact resistance was assessed in terms of the value of DA/IE, which is the ratio of the damage area (DA) to the impact energy (IE). The effects of the stacking sequence on impact resistance can be assessed in terms of the proposed nondimensional stacking parameter βT2. The relationship between DA/IE and βT2 was linear, and the value of (DA/IE)/βT2 indicated impact resistance of the tested material with dependence on neither fiber angle nor lamina thickness. The effects of the impact conditions, i. e., low/high impact velocity and hard/soft body impact, on impact resistance were discussed.