Delamination in Fiber Metal Laminates (GLARE) during fatigue crack growth under variable amplitude loading

This paper presents a study on the influence that load variations have on delamination shapes in Fibre Metal Laminates. Previously fatigue tested centre-crack tension specimens have been chemically etched to obtain the final delamination shapes. In addition, fatigue crack growth tests on similar specimens have been performed to investigate the formation of delamination shapes. For this purpose, digital image correlation has been used as strain measurement technique to record the delamination shapes in situ testing. An explanation is put-forward in order to understand the effects of variable amplitude loading on the formation of delamination shapes. A transition in delamination shapes was observed, but evaluating this observation using an analytical fatigue crack growth prediction model including the observed change in delamination shapes revealed no significant effect on subsequent crack growth.