A study on the inclusion of softening behavior in hyperelastic incompressible constitutive models

Hyperelasticity assumes that a strain energy function governs the problem (Holzapfel 2000). The energy is traditionally written in continuum mechanics by its well known reciprocity formulae W = σ:ε, so that ∂W/∂ε = σ (Marczak et al., 2006). Due to the short space the energy concepts behind hyperelasticity theory will not be exploited here and one of the many strain energy functions available is assumed. The material models used throughout this study are quickly reviewed below.