Stability of eccentrically stiffened plates

A finite element model is developed to investigate the elastic stability of eccentrically stiffened rectangular plates. The plate and beam elements form a structural system in which the neutral surfaces for bending in the x-z and y-z planes may not coincide. The additional forces resulting from the eccentricity of the middle surface of the plate and the centroids of the beams is taken into account in deriving the element stiffness and geometric matrix. The formulation is based on the behaviour of the plate-stiffener system and not on the behavior of the separate components. The results of this study clearly show the limitations of the equivalent orthotropic plate theory.