The effect of the multi-axiality of compressive loading on the accuracy of a continuum model for layered materials

Two methods of analysis of the internal instability of layered materials are discussed: the continuum approach and the piecewise-homogeneous medium model. Based on the results obtained within the scope of the model of a piecewise-homogeneous medium and the 3-D stability theory, the accuracy of a continuum theory is examined for incompressible non-linear materials undergoing large deformations. Two different loading conditions are compared: biaxial and uniaxial compression. The effect of the multi-axiality of loading on the accuracy of the continuum theory is determined for the particular model of hyperelastic layers described by the Treloar's potential (i.e. by a neo-Hookean type potential), which is a simplified version of the Mooney's elastic potential.