Abstract
Two lay-ups [0/±45/90] s and [0/90]2 s made of a T300 five-harness satin, woven-fabric-reinforced PEEK and containing a 12.7 mm diameter hole were charac terized in static tension. The high fracture toughness, GIC , of the thermoplastic matrix per mitted very little damage with no fiber breakage until final failure. In contrast, under reversed fatigue conditions, at a cyclic applied load equal to 55 % of the compressive strength, a large damage zone including fiber breakage developed. This was due to a rapid decrease of the resistance to splitting and to tow debonding in fatigue. The stiffness decreased with increasing size of the damage for both laminates. The [0/±45/90] s lay-up showed little variation of the residual tensile strength with increasing size of the fatigue- induced damage zone, whereas the [0/90]2 s showed a 30% increase. After the damage zone grew to 40 % and 15 % of the net cross section for the [0/90]2 s and the [0/ ± 45/90] s , respectively, the residual strength started to decrease.