Discrete element modeling for investigating the mechanical behavior of porous granular sea ice specimens under uniaxial compression

Abstract

The gas and brine pores within sea ice act as critical defects influencing its mechanical properties. To investigate the effects of pore characteristics on the mechanical behavior of sea ice under uniaxial compression, granular sea ice specimens were developed numerically using discrete element method (DEM). Local parameters of the model were calibrated by matching the simulated stress-strain curve with experimental uniaxial compression data. Pore characteristics (porosity, vertical distribution, and size) within the numerical specimen were configured based on field observations. Uniaxial compression simulations were conducted at a strain rate of 5.71 × 10⁻³ s⁻¹, and mechanical properties of uniaxial compressive strength, failure strain, Young′s modulus, crack propagation, and energy evolution were analyzed. Results showed that crack development within specimen became active only near peak stress, and the total crack count decreased with increasing specimen total porosity with shear cracks dominating the fracture patterns. Energy analysis revealed elastic strain energy predominated before peak stress, while dissipative energy increased rapidly after peak stress, exceeding elastic storage. Compressive strength, failure strain, and Young′s modulus of specimen decreased with increasing total porosity. Comparative analysis of specimens with different vertical pore distributions indicated that total porosity primarily affected sea ice strength, and vertical pore distribution governed crack localization. The spatial arrangement of pores showed negligible influence on sea ice mechanical behavior. Furthermore, the gas-to-brine ratio significantly affected sea ice mechanical response, with higher gas content reducing strength while promoting shorter, more numerous cracks. This study provides a mesoscale insight into pore-driven failure mechanisms in sea ice mesoscale.