When a ship navigates through ice areas, structural and vibration responses will be generated on the ship hull under the collision of sea ices. The magnitude of the response is highly correlated with the factors such as sea ice conditions, ship speed, structural stiffness, and measurement position. To be distinguished from the localized structural vibration, the global motion and vibration response of the ship can be referred to as ship bumping, which has a large impact on the functionality of the shipboard equipment, easily resulting in various issues such as lessening of the fastenings. The ship bumping in ice has been examined based on the data measured by the distributed accelerometers on board the icebreaker Xuelong II during the voyage in the Antarctic ice area. The events of ship bumping in ice are identified by the neural network method based on the time-frequency analysis. The ship bumping signals are separated by the frequency spectral analysis to extract the key parameters of the ship bumping in ice, such as the acceleration amplitude, pulse width, and the occurring frequency. The identification and analysis methods are finally established. On this basis, the data of ship bumping in ice of various typical scenarios are analyzed to investigate the influence of sea-ice environment, ship speed, and measurement position on the key parameters of the ship bumping. The requirements of the capability of shipboard equipment to withstand bumping under different sea-ice conditions are then summarized to provide references for the selection of polar ship equipment.

The numerical modeling of the ice formation in the ballast tank of polar ships has been established by adopting the volume of fluid (VOF) model in FLUENT to simulate the liquid phase and vapor phase, in order to analyze the influences of low temperature environment and ballast water capacity on the ice formation, and the heat transfer mode of the ballast tank of polar ships. The variations of the ice field in the computational domain with set-ups of different temperature environment and ballast water capacity are observed to analyze the influences of various factors and conditions on the ice formation in the ballast tank. It is found that the ice grows along the bulkhead to form a uniform ice layer, then grows transversely and vertically to form an ice layer completely covering the water surface, and finally grows downward along the bulkhead on the other side to form an arch shape as a whole. It is also observed that for the same ballast water capacity, the lower the ambient temperature, the faster the icing rate and the higher the icing degree; while for the different ballast water capacity, the lower the free surface, the better the effect of the hot air in the tank and the slower the icing rate. It can be concluded that the icing law of the ballast tank under low temperature is revealed through the numerical simulation of the ice formation of the polar ship ballast tank under low temperature. It can provide references for the deicing and winterization measures of the polar ship ballast tank.