ELASTIC STABILITY OF SQUARE STIFFENED PLATES WITH CUTOUTS UNDER BIAXIAL LOADING

A finite element method for the buckling loads on a longitudinally square stiffened plate with square cutouts is investigated under various combinations of biaxial loading at the plate boundary. The forces are assumed to act in the plane of the undeformed middle surface of the plate. The characteristic equations for the natural frequencies, buckling loads and their corresponding mode shapes are obtained from the equation of motion. The buckling load parameter for various modes of the stiffened plate with square cutouts subjected to in-plane biaxial loads, has been determined for various edge conditions. Numerical results are presented for a range of hole to plate size from 0 to 0.8. In the structural modeling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. The present approach is more flexible than any other finite element modeling in that the mesh division is independent of the location of the stiffeners.