The effect of longitudinal imperfections on thin-walled conical shells

Abstract

The load carrying capacity as well as the buckling and post-buckling behavior of conical thin-walled shells exposed to pressure loads are very sensitive to imperfections in the initial geometry. In this study, comprehensive work on the overall longitudinal imperfections created by welding and their effects on external pressure load carrying capacity has been performed by using finite-element models. The models were modified to include either one or two-line imperfection with amplitudes of six different magnitudes. The results presented here have confirmed some of the existing theories and provided new information concerning buckling of thin-walled conical shells. The load carrying capacity from buckling analysis was double the result from the Jawad theory for perfect models (without imperfection). In this research, increasing the cone height increased the imperfections’ weakening effect. In nonlinear analyses, the presence of an imperfection increased the buckling load capacity. However, increasing the number of imperfections resulted in less buckling load capacity than the model with one imperfection.