The compressive post-buckling behaviour of thin plates with cutouts

This thesis presents an investigation of the buckling and post-buckling behaviour of plates with cutouts under uniform compression. The theoretical analysis developed for this purpose is based on a combined finite element/-spline procedure which formulates a mathematical representation of the membrane stresses within the plate according to its flat and unbuckled state. These mathematical representations are then utilised in the subsequent energy analysis to determine the point of initial buckling and in a semi-energy post-buckling analysis to determine behaviour of plate after initial instability. A comprehensive study is made with regard to buckling loads, in-plane displacements, out-of-plane deflections and the internal stress variations of simply supported square plates with centrally located circular and square cutouts. The analysis caters for the nonlinearity due to changes in the buckled shape in the post-buckling region. The results have, however, been presented for both single term and multiterm solutions. An experimental investigation has also been conducted to obtain information on displacements and stresses. Plates with circular and square cutouts have been tested on a rig designed and manufactured at the College of Aeronautics. The present theoretical results have been compared with the theoretical and experimental results of other investigators. The theoretical results are shown to be in fairly good agreement with the experimental results of plates with circular and square cutouts of various sizes.