Some New Experiments on Buckling of Thin Wall Construction

Abstract

The first section of this paper describes a series of tests of the strength of thin-walled cylinders under a combination of torsion and axial compression or tension. Curves are obtained showing the strength of each of the several types of cylinders tested, under all possible combinations of these loads. All the curves obtained seem to have the same general form and the results suggest the possibility of finding a simple law by means of which a designer could determine the buckling strength of a structure under any combination of shear and normal stress, if he knows its strength under pure shear and under pure compressive stress. The second section describes tests made to investigate the independence of different possible types of buckling of a structure. A set of L-section struts, identical except for the widths of the sides, were tested in compression. With small widths the struts buckle as Euler columns but with the wider widths buckling of the sides, as plates hinged on three edges, occurs first. Great care was taken to eliminate the effect of initial eccentricities. The results check the well-known theories for these two types of buckling and indicate that, for practical purposes, the two types can be considered independently of each other. The results also illustrate how enormously the strength-weight ratio of thin wall construction may be affected by details of design.