Nonlinear viscoelastic-plastic material modelling for the behaviour of ice in ice-structure interactions

Abstract

In this paper, a three-dimensional constitutive ice model with nonlinear viscoelastic and plastic components acting in series is proposed for the dynamic simulation of ice-structure interactions. The former component corresponds to a nonlinear Burgers model, in which the deviatoric behaviour is viscoelastic and the volumetric behaviour is elastic. The Burgers model is combined with the well accepted Glen's law and Ashby and Duval’ law to describe the time-dependent behaviour and distribution in relaxation time. A hydrostatic pressure- and octahedral shear stress-dependent Tsai-Wu-type yield criterion is adopted to invoke the plastic state. The proposed ice model is assumed to be isotropic and is implemented in the commercial software LS-DYNA as a user-defined material. Verification of this model is implemented via simulations of creep and indentation experiments and via the simulation of a scenario of ice-rigid steel plate collision. The simulation of creep experiments shows that this material model can reflect the viscoelastic properties of ice quite well. The calculated contact force and pressure-area curves agree well with the results of indentation experiments. And the ice-rigid steel plate collision example yields reasonable results, indicating that the proposed model has a good capacity for describing the brittle behaviour of ice. The numerical verification proves that the proposed ice material model has a wide range of potential applications.