Instability of a Square Sheet of Rubberlike Material under Symmetric Biaxial Stretching

Abstract

Abstract The purpose of this work is to analyse the stability of the solution of the biaxial stretching test, in the case of Ishihara-Zahorski’s constitutive model of rubber-like material. Two solutions were obtained, the symmetric and asymmetric one. It was shown that the asymmetric solution is possible for significant forces and this solution is always stable. However, the symmetric solution is stable only for relatively small principal stretches. It is worth emphasizing that the stored energy function of the considered model is polyconvex.