Compressive buckling of rectangular composite plates with a free-edge delamination

Abstract

An experimental and analytical investigation is conducted on the compressive buckling behavior of orthotropic plates with a delamination. The plates, which have three simply supported edges and one free edge, are a simplified model of stiffener plates of a stiffened panel. A uniform width delamination is located at their free edges over the whole length. In the analysis, the Rayleigh-Ritz approximation method is adopted. A constrained point is introduced to allow the contact between the two delaminated surfaces. Imaginary springs about relative displacement and two relative slopes are introduced at the constrained point. With the constraint, buckling loads of physically admissible buckling modes can be obtained by ordinary buckling analysis. The global buckling load reduction is found to be significant and almost proportional to the delamination width. Local delamination buckling is found to occur when the delamination is located near the surface and its size is relatively large compared with that of the plate. The local buckling mode is different from the global one, and more wave number in loading direction and constrained points are necessary to obtain physically admissible solutions. The analytical results agree well with the experimental ones.