Probabilistic buckling analysis of suction bucket foundations for offshore wind turbines using non-homogeneous random fields

Suction bucket foundations are increasingly used for offshore wind turbines in combination with jacket substructures due to their noise-free installation and reduced embedment depth. However, the design of their thin-walled cylindrical skirts is driven by buckling due to negative pressure. Geometric imperfections have a significant influence on the buckling behavior. Due to inherent uncertainty, identifying geometric imperfections that represent realistic imperfections is challenging. Consequently, large reduction factors are applied in combination with very unfavorable imperfection patterns to account for uncertainties, which often results in conservative designs with higher material consumption. The uncertainty of geometric imperfections can be quantified using random fields, which are often assumed to be homogeneous, with constant statistical behavior across the shell surface.
Based on experimental imperfection data from lab-scale and full-scale suction buckets, it is demonstrated that geometric imperfections of suction buckets are characterized by non-homogeneity. Probabilistic buckling analyses are performed using non-homogeneous random fields as geometric imperfections applied to finite element models of suction buckets. ... mehrThe proposed approach generates imperfection patterns that are similar to the measured imperfection patterns. Results show that the mean buckling pressures from the non-homogeneous approach closely match the experimental results and are less conservative than those obtained from the classical homogeneous random field approach and from design buckling pressures according to Eurocode 3. The findings emphasize the influence of non-homogeneous random imperfection modeling on probabilistic buckling loads and indicate the potential for less conservative and more efficient skirt designs. This paper contributes to advanced probabilistic design methodologies for shell structures.