Experimental observations of fatigue damage in cross-ply laminates using carbon/epoxy ultra-thin plies

The damage mechanisms of cross-ply laminates under fatigue loading have been deeply studied during last years. In the case quasi-static loads so-called scale effect has recently acquired renewed importance after appearance ultra-thin plies. this work, experimental observation onset transverse and its progression in two different tension–tension cyclic is performed. First, a [04/903/04] laminate made plies with conventional thickness (150 g/m2) analysed. After looking for expected case, [04/90/04] single 90? ply (30 studied. All specimens carefully examined by means an optical microscope, detecting non-conventional types damages [04/90/04]. change involving microscopically detailed, meaning evidence delay 90° layer loading. This shows existence concerning mechanisms.