Fatigue damage calculation of ship hulls caused by ice loads in broken ice fields

Fatigue damage induced by ice loads is a key concern as ships operates in broken ice fields where a sea route is normally developed. This paper proposes a method for calculating fatigue damage of a ship structure advancing in broken ice, on the basis of numerical simulations. A random broken ice domain with polygon-shaped ice floes is generated using Centroidal Voronoi Tessellation (CVT) algorithm. A discrete element method (DEM) is employed to imitate ice-ice and ice-structure interactions, and produce the required ice loads data for fatigue assessment. A Weibull model is used to describe the probability distribution of ice load peaks. The fatigue stress is determined using structural beam theory. Finally, the fatigue damage is estimated based on the Palmgren–Miner rule. An example of fatigue calculation is presented with hypothetical scenarios in broken ice fields, and comparisons of the proposed method are made against the ShipRight FDA ICE procedure.