EFFECTS OF LAYER WAVINESS ON THE COMPRESSION STRENGTH OF THERMOPLASTIC COMPOSITE LAMINATES

Layer waviness was investigated in T300/P1700 carbon/polysulfone composite laminates under static compression loading. A three-step procedure was used to fabricate isolated layer waves into the central 0-degrees layer of [90(2)/0(2)/90(2)/0(2)/90(2)/0(2w)]s laminates. Efforts were made to insure that this three-step procedure itself did not degrade the laminate quality. Layer wave geometries up to 1.5 layer thicknesses in amplitude and as short as nine layer thicknesses in length were tested. The more severe wave geometries produced reductions in static strength as high as 36%, although the wavy 0-degrees layer accounted for only 20% of the load carrying capacity of the laminate. Specimen failures were sudden and catastrophic. Brooming failure, characterized by through-the-thickness splaying of the layers and numerous delaminations near the waviness, was the common failure mode.