Experimental Investigation of the Buckling of Plates with Residual Stresses

This is a summary of local buckling tests of plate elements in square columns built up by welding. The experiments were conducted to verify theories for the elastic and elastic-plastic buckling of plates with emphasis on the effect of residual stress. This was part of a general study on the strength of welded columns and the influence of residual stress on plate buckling. Both ASTM A 7 and A 514 steels were used. The square section simulated plates simply supported at the unloaded edges, and the length of the column was chosen so that end conditions had no effect either on the residual stress distribution or on the local buckling strength of the columns. Short columns were tested in the “as-placed” condition in a mechanical-type testing machine. The transverse deflection (local buckling) of the plates was measured at a number of cross sections by a 1/10,000 in. dial gage fixed to a frame held manually. The “top of the knee” method was used to estimate the bifurcation load. The experimental results showed good correlation with theoretical predictions including the effect of residual stress for elastic buckling and for elastic-plastic buckling based on the total strain theory. The results of experiments indicated that considerable post-buckling strength may be expected for elastic buckling of plates, although not for elastic-plastic buckling.