Crystal Plasticity Finite Element Modeling of Elastic-Viscoplastic Deformation of Ice Single Crystals

Abstract Ih ice single crystals with densely packed hexagonal structure exhibit elastic-viscoplasticity anisotropy under low strain rate loading conditions, which is directly related to the crystal structure. In order to reflect the elastic-viscoplastic deformation properties of ice single crystals, a crystal plasticity finite element (CPFE) numerical model considering loading rate and crystal orientation dependence based on dislocation slip mechanism was established. In the model, Hooke’s law is followed for elastic deformation, and Schmidt’s law is used for plastic deformation to establish the relationship between shear strain rate and shear stress on different slip systems. The calculation accuracy of the model was verified by comparing with the published results of constant strain rate deformation of ice single crystals. On this basis, the effect of crystal orientation on the deformation of ice single crystals was investigated through the loading simulation at different angles (0°, 15°, 30°, 45°, 60°, 75°, 90°) with the C-axis, and the mechanical response, the activation condition of slip systems and slip ability were analyzed when slip occurred under different crystal orientations. The results show that the numerical simulations of ice single crystals based on the established CPFE model can reasonably characterize the elastic-viscoplastic deformation characteristics. Except for crystal orientations of 0° and 90°, all ice single crystals under other crystal orientations exhibit stress softening characteristics, which are related to the activation of basal slip systems. Under the same deformation conditions, basal slip is most easy to occur. This work can provide a theoretical model at crystal scale for the establishment of multi-scale constitutive relations of polycrystalline ice based on microstructure evolution.