Study on Ice Load Characteristics of a Polar Ship under Oblique Sailing Based on Discrete Element Method

Objectives With climate warming, both the number of polar navigating vessels and the duration of navigable periods are increasing. Oblique navigation in brash ice regions, a typical operating condition for polar vessels, heightens the uncertainty of ice loads on these ships, thereby increasing navigational risks. Methods Using a specific polar ship type as the research subject, this study applies the Discrete Element Method to accurately predict ice loads on ships operating in brash ice regions. First, a numerical model of the target ship type is established, and its accuracy is validated by comparing with experimental data. Next, ice loads experienced by the ship during oblique navigation are calculated by setting various oblique sailing angles, speeds, and ice thicknesses. Finally, an in-depth analysis is conducted on the distribution characteristics and variation trends of ice loads under different drift angle conditions. Results The study shows that with an increase in drift angle, both brash ice resistance and lateral force on the ship exhibit nonlinear growth. Under conditions of a speed of 0.6 m/s, 60% ice concentration, and an ice thickness of 0.01497 m, the brash ice resistance and lateral force at a drift angle of 15° in oblique navigation increase by 4.25 and 6.04 times, respectively, compared to straight navigation. During oblique navigation with drift angles exceeding 10°, caution should be exercised when increasing speed or entering regions with thicker ice, as sudden surges in brash ice resistance and lateral force on the ice-facing side may lead to adverse effects. Conclusions The research findings provide reliable data support for safety assessments of ships operating under oblique navigation conditions in polar brash ice regions, offering a valuable reference for predicting and studying ice loads on polar vessels in such conditions.