Symmetric Cauchy stresses do not imply symmetric Biot strains in weak formulations of isotropic hyperelasticity with rotational degrees of freedom.

We show that symmetric Cauchy stresses do not imply symmetric Biot strains in relaxed weak formulations of finite isotropic hyperelasticity with exact rotational degrees of freedom. This is contrary to claims in the literature. It is noted that in the linear isotropic case with skew symmetric infinitesimal rotational degrees of freedom a similar discrepancy does not arise. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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