Large deformation effects in the postbuckling behavior of compositeswith thin delaminations

Abstract

The postbuckling deformation of composites with thin film delaminations is modelled through a procedure that is based on large deflections of the delaminated layer. The results on the stiffness and strain energy are compared with an approximate model that does not include those effects. The influence of large deflections on the energy release rate which characterizes delamination growth is also studied. These effects are found to be significant, leading to a less stiff and more growth resistant system. Furthermore, the end fixity conditions are found to play an imprortant role in the postbuckling behavior. Finally, results of experiments that were performed on the postbuckling characteristics of kevlar/epoxy specimens with thin delaminations are discussed.