Elastic limit load estimation including similarity approach for different end conditioned conical shells with high semi-vertex angle under axial compression

Abstract

This study investigates the stability loss of thin walled conical shell structures under axial loading. More specifically, conical shells with semi-vertex angle greater than 65 degrees(beta(c) > 65 degrees) and with different bottom edge radial stiffness were studied in order to fill the gap in existing literature. The effects of geometrical parameters of the structure on the load bearing capacity were determined. Conical shell structures with high semi-vertex angle and different boundary conditions display highly non-linear character under axial loading, hence conventional analytical approaches are not adequate to predict the limit load. Therefore, a new method was proposed in this study which can accurately predict the limit load of these structures. The deviation between the proposed method and numerical results was found to be +/- 13%, while it was one order higher (+ similar to 300%) in classical shell theory, based on the configuration. Furthermore, similarity parameters were suggested to increase the range of application of the proposed method. Similarity parameters enable researchers to work with scaled-down models which are capable of simulating the behaviour of real-time-scale models. In addition, the effect of geometrical initial imperfections on the load bearing capacity was investigated and a new reduction coefficient was identified which is much more accurate compared to the overly conservative standard counterpart. A numerical model was developed with COSMOS/M software. This model was validated with experiments, and then was used for the parametric study.