Fatigue Life Prediction of Ship Structures Under Varying Sea States Using Numerical Simulations

Abstract

The accurate prediction of fatigue life in ship structures is essential for ensuring operational safety and long-term performance in harsh marine environments. This study presents a contribution to the MADELEINE Project (MeAsurement of sea state conDitions to monitor the ship fatiguE Life and Enhance IN real-time conditions the safEty of navigation), which aims to develop advanced tools for fatigue monitoring and prediction. In this work, numerical hydrodynamic simulations were performed to evaluate the dynamic response of a container ship subjected to wave-induced loading across multiple sea states and operating conditions. Response Amplitude Operators (RAOs) for vertical bending moments and shear forces were computed for various wave directions and ship speeds, and results were compared with classification society standards. Using North Atlantic Sea state data, fatigue stresses were estimated and used to evaluate fatigue life through a probabilistic approach based on Palmgren-Miner’s rule. Focus was given to welded joints, which are known to be critical fatigue-prone areas due to stress concentrations. The findings reveal the limitations of simplified regulatory methods and demonstrate the potential of direct numerical simulations in providing more accurate fatigue predictions. This study lays the groundwork for future integration of finite element analysis (FEA), with the goal of enabling real-time structural health monitoring and supporting predictive maintenance in maritime operations.