Propagation of Interacting Cracks in Offshore Wind Welded Structures Through Numerical Analysis

Abstract

This study investigates the behavior of interacting surface cracks at the circumferential weld toe of monopile-supported offshore wind turbines. Relying on a numerical model that explicitly considers weld profiles, we explore the impact of crack interaction and loading scenarios on crack propagation. Our findings reveal that, initially, surface cracks grow independently, resembling single crack behavior. However, a pronounced interaction effect accelerates their growth as cracks propagate further, potentially leading to crack coalescence, high stress intensity factors, and reduced fatigue life. Consequently, this work highlights the need for integrating specific weld geometry representation in numerical models, as neglecting this can lead to significantly inaccurate fatigue life estimates in typical practical applications. Moreover, this study points out the challenge in accessing representative crack growth material parameters, vital for accurately evaluating the fatigue life of structural connections in offshore wind turbines.