Experimental assessment of fatigue damage mechanisms in [04/90n]s laminates using carbon-epoxy ultrathin plies

Abstract

The damage mechanisms of cross-ply laminates under fatigue loading have been deeply studied during last years. In this work, the experimental assessment of two different cross-ply laminates under T-T loading (stress ratio of 0.1) is performed. Firstly, a [04/903/04] laminate made of plies with conventional thickness (150gsm) is analysed. After looking for the expected fatigue damage mechanisms in this case, a [04/90/04] laminate with an ultrathin 90⁰ ply (30gsm) is assessed. Both case studies have been experimentally carried out under the same fatigue conditions and carefully examined by means of an optical microscope. The development of the cycling damage mechanisms in each laminate is expounded, comparing their initiation and propagation.