Buckling and postbuckling of delaminated composites under compressive loads including transverse shear effects

Abstract

The deformation of delaminated composites under axial compression is analyzed by a one-dimensional beam-plate model. In this model, a formulation that accounts for the transverse shear effects is also presented. With the perturbation technique, analytical solutions for the critical instability load and the postbuckling deflections are obtained. All possible instability modes, namely, local delamination buckling, global plate buckling, and coupled global and local (mixed) buckling, are considered. Specific emphasis is placed on studying the transverse shear effects on both the critical load and the postcritical characteristics, as well as the influence of the geometry such as that of the location of the delamination across the thickness. The postbuckling solution is used in conjunction with a /-integral formulation to study the postcritical characteristics with respect to possible quasistatic extension of the delamination and the energy absorption capacity of a beam.