Failure of Thin-Walled Members under Patch Loading

The Finite Element Method of analysis was used to determine the buckling loads of the web plate under patch loading together with simple supporting shear forces. Combinations of patch loading with shear loading or with in-plane bending moment are also studied. The results are presented in the form of interaction curves which show that the applied edge load necessary to buckle the panel is reduced by the presence of either an additional in-plane moment or shear. Tests are carried out on light gage cold formed troughs. The test results show that there is a considerable amount of post buckling strength for panels having high slenderness ratios. A linear relationship exists between the ratio of the ultimate load to the buckling load and the relative length of the loaded patch and the slenderness ratio of the panel. Failure of all test panels is associated with the formation of a localized yield curve under the load.