Numerical analysis on failure mode of 3D columnar polycrystalline ice based on discrete element method

The microstructure of sea ice plays a crucial role in governing its macroscopic mechanical properties. Investigating the relationship between the microstructure and mechanical behavior of sea ice at the ice crystal scale poses significant challenges in the field of ocean engineering, particularly in cold regions. The mechanical properties of natural sea ice are inherently complex due to the intricate structure of ice crystals. The crystal structure of sea ice includes the ice crystal morphology, grain size, and C-axis orientation. Granular ice consists of small ice crystals with random orientations, whereas columnar ice typically exhibits significant anisotropy. When loading is applied along the ice crystal growth direction, its compressive strength is much higher than when the load is applied perpendicular to this direction. This anisotropy generates complex loading conditions during the interaction between sea ice and structures. Additionally, grain size is a key influencing factor, with peak failure strength decreasing as the grain size increases. To accurately replicate the unique mechanical properties of natural sea ice, this study presents a numerical model that captures the failure behavior of columnar polycrystalline ice using the Discrete Element Method (DEM). The anisotropic properties of columnar ice are modeled by simulating uniaxial compression in both the vertical and horizontal directions, and the model's validity is confirmed through comparison with experimental data. Furthermore, uniaxial compression simulations were conducted for sea ice samples with varying grain sizes and crystal orientations. The results show that both grain size and crystal orientation significantly influence the fracture characteristics and failure modes of sea ice. These findings also confirm that the Discrete Element Method (DEM) is an effective tool for studying the failure behavior of threedimensional columnar polycrystalline ice.