Effects of Layer Waviness on the Compression Response of Laminates
SourceLayer waviness was investigated in T300/P1700 carbon/polysulfone composite laminates under static compression and compression fatigue loading. A three-step procedure was used to fabricate isolated layer waves into the central 0° layer in [902/02/902/02/902/02u]s laminates. Layer wave geometries up to 1.5 layer thicknesses in amplitude and as short as 9 layer thicknesses in length were tested. The more severe wave geometries are shown to produce reductions in static strength as high as 36%, although the wavy 0° layer accounts for only 20% of the load-carrying capacity of the laminate. Moderate wave geometries produce a one-and-one half decade loss of compression fatigue life as compared to specimens without layer waviness. Specimen failures in both static compression and compression fatigue tests 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.