Analysis of orthotropically modeled stiffened plates

Abstract

In the past, formulations for technically orthotropic plates appear to have been based only on Kirchhoffs assumptions for the classical thin plate theory. In the present paper, the authors have studied a formulation applicable to eccentrically stiffened plates based on the Reissner-Mindlin plate theory. Due to the formidability of the 10th-order governing equations of this formulation in yielding closed form analytical solutions, recourse has been taken to the finite element method. The range of validity of the orthotropic model, so dependent upon the proximity of stiffeners, has been assessed and demarcated by comparison with a more general discrete plate-beam model using the techniques of dimensional analysis. Finally, results arc presented for the geometrically non-linear orthotropic plate and comparisons are made with the work of earlier investigators to highlight the fact that the degree of eccentricity of stiffeners is an important factor to be taken into account, in addition to the volumetric ratio between plate and stiffeners.