A rate and pressure dependent elastoplastic material model for glacial ice colliding with marine structures

Abstract

An elastoplastic ice material model with a rate and pressure dependent yield criterion is proposed in the present study for ice-structure collision simulations. The yield criterion is based upon the Tsai-Wu failure envelope which is formulated in the present study to evolve with the strain rate. The relation between ice strength and loading rate is known to be disrupted at the ‘ductile-to-brittle transition’ strain rate. Hence, the yield locus evolves differently in ductile and brittle regimes, which is herein modelled using two different strain rate-strength equations. These equations, obtained from the literature, are based on more than 100 physical tests on freshwater polycrystalline ice, including iceberg ice samples. The constitutive laws, written in Fortran, are implemented in Abaqus as vectorised user material (VUMAT). The proposed material model is validated against two physical ice crushing tests with different indentation speeds, 1 mm/s and 100 mm/s.