Effect of Moving Ice Loads on the Plastic Capacity of a Ship’s Structure

The IACS unified polar rules define the design ice load as a glancing impact on the bow shoulder. The load and structural response model in the polar rules ignore the tangential motions and assumes the interaction occurs at one location. If the impact duration were sufficient, the ice may “score” along the hull during a glancing impact. This paper examines the questions of how structure responds to moving loads, in comparison to normal loads. An explicit nonlinear numerical model was created and validated against full-scale physical experiments. Moving load scenarios were then simulated. The structure’s capacity to withstand moving loads causing “progressive damage” was found to be generally less than its capacity to withstand static loads.