Hyperelastic constitutive models for geomaterials: Extension of existing models to include finite strains and their comparison

Abstract

The objective of this article is to present an extension of existing hyperelastic constitutive models for geomaterials to include finite strains and to examine and compare the model responses. Several existing representative isotropic hyperelastic models with pressure-dependent bulk and shear moduli are reformulated to accommodate them to finite strains, as well as to tensile stress range. To be consistent with the multiplicative finite strain elastoplasticity, the stress versus the elastic strain relation, together with the fourth-order elastic tangent moduli tensor, in the description relative to the intermediate configuration is derived for each hyperelastic model. The spatial and material descriptions of the hyperelastic models are also derived. A systematic parametric study with a particular focus on the pressure-dependent property of the elastic tangent moduli is performed to examine and compare the model responses. The analysis reveals significant difference in the model responses depending on the types of models. Notably, some models exhibit unreasonable decrease in stress in the process of triaxial compression.