Discrete element analysis of ice loads on polar ships under pilotage of icebreaker

The pilotage of icebreaker can effectively guarantee the navigation safety of merchant ships in polar ice regions. The dilated polyhedron based on the Minkowski sum theory is used to generate the sea ice element with irregular shapes. The bond-failure model of the dilated polyhedron element is developed to simulate the breaking process of sea ice. Accordingly a dilated polyhedron based discrete element method (DPDEM) is established. The interaction between ship hull and sea ice is simulated with the DPDEM, while the ice load on the ship hull is analyzed. The ice load on ship hull which is based on the hull model of icebreaker Xuelong is simulated using the DPDEM. The result is validated with the result of the Lindqvist formula and the Riska formula which are most commonly used for the ice load analysis on ship hull. The validation illustrates that the results by the DPDEM and the empirical formula are close. It is convincing that the DPDEM can be used for the ice load analysis on ship hull. Moreover, the ice loads on ships under the pilotage of icebreaker is simulated using the DPDEM. The ice resistance under different ship speed and ratio of ship width is analyzed. The DPDEM can effectively be used for the analysis of ice load on the ship hull. The results by the DPDEM can provide important references for the ice ship design and navigation safety.