Critical buckling predictions for plates and stiffened panels from natural frequency measurements

The paper establishes a linear relationship between the square of natural frequency and applied compressive loading for a simply supported plate. This relationship enables the critical buckling load to be predicted by extrapolating from the natural frequencies obtained when the plate is lightly loaded. If the fundamental natural frequency and the critical buckling load have different mode shapes, buckling predictions can be made by extrapolating from higher natural frequencies. Shear loading causes a continual change in the mode shape as the loading is increased, and the critical buckling load can be estimated approximately by curve fitting and extrapolation. Similar results are obtained for simply supported stiffened panels.