Bifurcation Buckling of Aboveground Oil Storage Tanks under Internal Pressure

Abstract

This chapter deals with finite element bifurcation buckling analysis for both the sidewall-to-bottom and the sidewall-to-roof joint under internal pressure. Elastic-plastic large deformation analysis is carried out for axisymmetric shells. The axisymmetric shell finite element used is a conical frustum element. The tangential displacement and the circumferential displacement are assumed to be linear and the normal displacement to be cubic with regard to the meridional coordinate of the shell element. Prebuckling deformation analysis is equivalent to elastic-plastic large deformation analysis of axisymmetric shells subjected to axisymmetric load. In this analysis, the updated Lagrangian formulation is used. To obtain stresses on the yield surface during all plastic deformation, the elastic-predictor radial-return method is used when the beginning-of-step stress at the integral point is elastic or unloading. A trial state based on an elastic assumption is first obtained, and the stress is then corrected with an adjustment in yield surface radius.