The International Association of Classification Societies (IACS) Polar Class (PC) requirements are widely accepted by the industry as the design standards for vessels operating in polar regions. The PC requirements consider the bow shoulder collision with infinite ice as the base scenario. The Popov collision model (Popov, 1976; Daley, 1990), updated with a pressure-area ice pressure model, was adopted for calculating the ice loads on the hull. The Popov collision model considers that the ship-ice impact is so quick that a 3-D collision can be modeled by an equivalent 1-D collision. All motions between ship and ice are mapped onto the normal direction to the hull at the collision point. No collision energy is assumed to be dissipated by the friction force since sliding velocities are ignored. It is of interest to assess the effects of the simplifications in the Popov model using a numerical method which can simulate the collision mechanism with a high level of sophistication.
A numerical study of the Popov collision model of ship-ice interaction is presented in this paper. In the study, ship sliding motions and frictions between hull and ice were included in the six-degree-of freedom ship-ice collision model using LS-DYNA software. The output and checked items include the force time histories, maximum force value, ship/ice motions, contact areas and positions, etc. A parametric study was carried out to quantify the effects from varying mesh sizes, ship-ice friction coefficients, ice elastic modulus and ice buoyancy force using the FE model simulation. The effects of simplifications of the Popov analytical model were assessed through the comparisons of the results produced by the analytical model and the numerical model.
