A THEORETICAL AND EXPERIMENTAL INVESTIGATION OF BUCKLING INDUCED DELAMINATION GROWTH

A THEORETICAL and experimental investigation of a laminated plate with an embedded, initially circular delamination, loaded in uniaxial compression is described. The main issue concerns the combined postbuckling and crack growth behaviour in general situations at arbitrary crack contours and applied to fibre-reinforced carbon-epoxy composite plates. In a numerical procedure a standard FE-code is used to solve the structural postbuckling problem and extended to account also for contact effects. To predict interlaminar crack growth an automatic finite element procedure was employed for the purpose. Delamination growth in laminates was detected by the aid of acoustic emission. After successive crack increments. the evolution of the delamination front was mapped using an ultrasonic C-scan technique and also for comparison by X-ray. Predicted and observed results are compared as regards postbuckling behaviour and in particular the magnitude and shapes of delamination growth fronts.