Postbuckling behavior of longitudinally compressed orthotropic plates with three-dimensional flexibility

Postbuckling results for the average longitudinal compressive stress vs applied displacement are obtained for aluminum (isotropic), aluminum/epoxy (quasi-isotropic), and 45-deg graphite/epoxy (orthotropic) plates using classical (Kirchhoff) and conventional transverse shearing theories. An analysis of the results obtained shows that, in the postbuckling range, the classical theory cannot provide reasonably accurate results even for thin plates.