Development of the Analysis Procedure for the Ice-Induced Fatigue Damage of a Ship in Broken Ice Fields

Abstract

A simplified analysis method was developed to evaluate the fatigue damage of an ice-going ship under broken ice conditions. The ice resistance, which is available in the early design stages of an ice-going vessel, and the hull form information were used to estimate the local ice load acting on the outer-shell of the ship. The local ice load was applied to a finite element analysis model, and the Weibull parameters of the local stress range at the target fatigue point were derived. Finally, the fatigue damage was evaluated by applying the S–N curve and Palmgren–Miner rule. To verify the proposed method, numerical analyses using the direct approach, which takes into account the detailed interaction model among the fluid, structure, and ice, were performed under the same conditions. Fatigue analyses of the Baltic Sea for actual ice conditions were performed to check the validity and applicability of the proposed method, and the resulting fatigue damage was compared with that obtained by the classification society’s recommended practice.