Abstract
When thin sheet metal was first used for aircraft, the design was in accordance with the usual laws of elasticity, and when buckling occurred in any part it was considered as failure. Frequently it was observed, however, that the buckling disappeared after the load was removed, without permanent deformation. This led to the study of thin sheet metal when used above the stability limit. The paper considers two methods of designing structures for thin sheet metal—one is to endeavor to make the buckling load correspond to a stress equal to the elastic limit of the material, and the other is to allow the structure to go into the buckled state at a stress below the elastic limit and then to determine the allowable load on the structure before permanent deformation would take place. It may be possible that a photoelastic study of buckled sheets would lead the way to a solution.
