A UNIAXIAL NONLINEAR VISCOELASTIC CONSTITUTIVE RELATION FOR ICE

The present paper concerns the description of uniaxial deformation and failure of ice in uniaxial compression in terms of a nonlinear viscoelastic constitutive theory. The constitutive model incorporates explicit dependence upon micro-structural defect growth and assumes the form of a so-called modified superposition integral containing a linear kernel which depends only upon time. Predictions based upon this model are shown to agree qualitatively with experimental results for creep (constant stress) and strength (constant strain-rate) tests on ice. In addition, specific empirically deduced relationships between stress, strain, strainrate and time at certain critical points in these standard tests are shown to result directly from the constitutive theory as special cases.