Degradation of the compressive strength of rectangular plates due to initial deflection

The paper addresses the problem of the influence of initial deflections on the collapse strength of thin rectangular plates in longitudinal compression. Measured data on distortions of stiffened plating in ships are considered in studying the strength of plates. For comparison of the strength values, the initial deflections are normalised by an energy measure and by the commonly employed amplitude to thickness ratio. It is suggested that this energy measure is able to provide an integral measure of the degree of initial deflections.