Challenges in calculation of critical buckling load of tubular members of jacket platforms in finite element modeling

Abstract

Accurate estimation of the capacity curve of offshore jacket structures to achieve performance levels and ductility is of great importance. Proper modeling of compressive members to correctly investigate global and local buckling is crucial in estimation of the capacity curve. Buckling modes and deformations due to local buckling can be considered, if the compressive braces are modeled by shell or solid elements. The purpose of this paper is to achieve the correct compressive behavior of braces with solid type elements and investigate the effects of five different parameters such as D/t, L/D, mesh size, mesh size ratio, and imperfections. ABAQUS FE software is used for this purpose. The percentage of difference between model results and ISO equation for critical buckling load and the best choice of the above variables has been presented to achieve the maximum precision. Also the effect of these parameters on buckling capacity curve of tubular members has been estimated. The percentage of the effect of mentioned parameters is shown as separate pie charts. Consequently, mesh size ratio has the greatest effect on elastic stiffness and post-buckling strength. On the other side, the imperfection value is the most effective parameter on critical buckling load.