Investigation of uncertainties in buckling and post-buckling behavior of typical braces of offshore jacket platforms by using Solid elements in ABAQUS

In order to attain the performance levels of the structure and establish its ductility, accurate calculation of the ultimate capacity of offshore structures, particularly jacket-type fixed platforms, is crucial. The ultimate capacity of these structures will fluctuate throughout the course of their lives due to a variety of factors, including the development of fatigue cracks in joints, corrosion of structural elements, environmental loadings, and accidental loads. However, because to its enormous impact, it is crucial to accurately estimate both global and local buckling of compressive members when assessing the final overall capacity of the structure. Compressive braces' modes and deformations due to local and global buckling will be examined inherently if they are modeled using 3D Solid or Shell elements. In this paper, using Abaqus finite element software, the effects of various parameters governing the modeling of these elements, comprising the number and ratio of meshing, the imperfection value, and the geometric proportions of members, on the buckling behavior of braces are investigated. Besides, comparison of the results derived from the modified modeling with the ISO equations related to buckling of tubular members is provided. This study has been done with the aim of considering the best combination of these parameters in order to properly estimate the buckling response of braces in computer modeling.