Unique critical state single-surface anisotropic hyperplasticity
William M. Coombs · Durham Research Online (Durham University) · 2013
This paper presents the theoretical development and algorithmic implementation of a single surface anisotropic hyperplasticity model. The model extends the isotropic family of models developed by Coombs and Crouch (2011) through (i) intro- ducing anisotropic shearing into the yield surface and (ii) using a more physically realistic pressure sensitive elastic free energy function. This model overcomes the difficulty of determining the constants of the isotropic two-parameter surface by analytically relat- ing them to a single experimentally measurable physical quantity, namely the normalised hydrostatic position of the Critical State. This link results in a unique Critical State surface, invariant of the level of anisotropy inherent in the yield envelope. The model is compared with experimental data on Lower Cromer Till and contrasted against the SANIclay model.