On pre-buckling configuration of functionally graded Mindlin rectangular plates

In this study, the pre-buckling configuration of the functionally graded (FG) plates whose mechanical properties vary through the thickness is discussed. Since the bending and stretching equilibrium equations of this type of FG plates are highly coupled equations, the plate deflects under minimal external in-plane loads when they act on the mid-plane of the plate. Consequently, the FG plates under external in-plane loads on the mid-plane do not remain flat and cannot exhibit bifurcational buckling. Some researchers believe that the FG plates cannot be assumed to be flat under in-plane loads. Nonetheless, some others have studied the buckling problem of FG plates with the flat plate assumption in the pre-buckling configuration. Two view points regarding to the buckling problem of FG plates are investigated and the conditions of accuracy of each view point are studied.