Numerical study of hot‐spot stresses in single sided welded T‐Joints for fatigue assessment of offshore foundations

Abstract

The growing expansion of offshore wind energy requires more accurate assessment strategies for fatigue life of welded joints. T‐Joints are a frequently structural detail in monopile‐based offshore foundations, for example at boat landings and secondary steel attachments. During global tower bending due to wind loading or wave impact, secondary stresses result in the attached component, affecting the stress distribution of the primary structure. This work investigates hot‐spot stresses across a large geometric parameter set based on the hot‐spot stress approach to capture the influence of local curvatures and stiffness on stress concentration. A Design of Experiments approach was applied to detect potential interactions and to identify the governing factors affecting the stress concentration. It could be shown that the hot‐spot stress approach can be applied directly to the investigated T‐Joints.