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The paper presents an investigation on the behavior of a plate with variable thickness and simple boundaries under inplane compressive loads using energy, finite differences, and finite elements methods. The more important parameters affecting such behavior, are the spatial
location of the corrosion patch, the corroded surface and thickness at corroded place. These are studied through changing them at practical ranges, and the more crtical cases are indicated. At first the critical load of plate is calculated using energy and finite differences methods which is a basic parameter in all such studies. To consider the effect of midplane variation due to corrosion, FEM is employed via ALGOR software. The
geometric and material non-linearity are taken into account and the effect of
progressive corrosion on gradual strength
reduction is traced.