The subperforation flatwise impact damage resistance of carbon fiber/PEEK (CF/PEEK) laminated composites (APC-2/AS4) was evaluated under low and high velocity impact tests. The stacking sequences of the specimens were [0°/30°/0°/-30°]s, [0°/60°/0°/-60°]s and [0°/45°/90°/-45°]s. The drop weight test system as the low velocity impact test and the air gun test system as the high impact test were used to consider the effect of impact velocity on damage area. The damage areas after impact were measured with the ultrasonic C-Scan. The impact damage resistance was assessed as the ratio of the damage area (DA) and the impact energy (IE). To estimate the effect of the stacking sequence related to the impact resistance (DA/IE), the stacking parameter β, which indicates the difference in in-plane stiffness between the adjacent laminae, is proposed. From the experimental results, it is obtained that the stacking parameter β is valid to select better stacking sequence of composite laminate for impact resistance.
