Numerical Prediction of Fatigue Crack Initiation Locations in Offshore Tubular T-Joints using Actual and Idealized Weld Geometries

Kurzfassung

The rising demand for offshore wind power necessitates more precise fatigue strength predictions for welded joints. A key challenge is accurately predicting crack initiation locations, influenced by specific weld geometry. This paper investigates the variation in fatigue crack initiation locations of manually welded steel tubular T-joints during high-cycle fatigue experiments. The joints under investigation represent scaled-down versions of those in offshore support structures. We compare experimentally identified crack initiation locations via fractographic analysis with predictions from finite element analysis. Simplified weld geometries using the structural hot-spot stress approach prove unreliable. Integrating the 3D weld surface scans into simulations improves prediction accuracy considerably. Our findings highlight the importance of actual weld geometry in enhancing the reliability of fatigue strength predictions for tubular T-joints in offshore structures and serves as an early proof of concept for the showcased approach