In-situ mechanical testing of Arctic sea ice is of great significance for ensuring the safety of ice navigation and supporting the design of polar ships. During the 15th Chinese National Arctic Research Expedition, systematic in-situ sea ice mechanical tests were carried out in the high-latitude region of the central Arctic Ocean (84°57′N-89°49′N). A total of 63 in-situ borehole strength tests, one full-thickness in-situ cantilever beam flexural strength test, and 43 small-scale three-point bending strength tests were completed. Among them, the borehole strength test and the in-situ cantilever beam test were both conducted by China for the first time in the polar region. Preliminary analysis shows that the borehole strength increases with latitude, rising from 3.9 MPa at 84°57′N to 14.2 MPa at 89°49′N. The flexural strength tests reveal a certain size effect: the full-thickness flexural strength obtained from the cantilever beam test is 226 kPa, while the arithmetic mean of the small-scale three-point bending strength is 384 kPa. This paper provides valuable field data for understanding the mechanical properties of late-summer Arctic sea ice and can support the design of China’s polar engineering equipment and the assessment of navigation safety of ships in ice-covered waters.

The design and construction of polar ships rely on the prior knowledge of the safety of ships sailing in ice regions. However, the current available trial data and experience in ice regions are extremely insufficient in the world, which requires the development of effective and reliable prediction methods. The current development of sea ice mechanics and engineering is still far from maturity. It is therefore difficult to form a reliable method for the performance prediction of ships sailing in ice regions based on theoretical analysis and numerical simulation. Therefore, it has been accepted by the international academia and industry that the ice tank testing is the only reliable way to predict and assess the performance of ships sailing in ice regions. The state-of-the-art of the experimental prediction of performance for polar ships sailing in ice regions is introduced from three aspects of resistance, propulsion and manoeuvrability. And the key technologies are reviewed to provide references for the industry to fully understand the ice tank testing techniques.