Estimation of Ship Bow-Iceberg Impact Forces with Consideration of the Sliding Effect

摘要

A simplified method to estimate the impact force in ship bow-icebergcollisions is presented. The eccentricities of both iceberg and ship areincluded. The friction at the contact point is also included so that thesliding effect is taken into account. The impact force is determined by aconcept of energy consideration including both on normal and tangentialdirections during the collision. This method consists of three steps. First,a full 3D model is applied to assess the energy dissipation in a ship bowicebergcollision based on impulse momentum and energy conservation.Second, the force- and energy dissipation-indentation relationships aredetermined by the pressure-area relationship and the contact areaindentationrelationship. Third, the impact forces are derived by usingthe calculated dissipated energy and the force/energy-indentationrelationship from the previous two steps. This method was applied in thecase studies to investigate the effects of the iceberg shapes, the normalframe angle of the ship, the friction coefficient and the ice pressure-arearelationship on the impact force. The impact forces for various icebergmasses obtained by the present method were compared with the designloads calculated according to IACS’s rule for Polar Ships. Thedifferences were analyzed and discussed in this paper.