Sensitivity based virtual fields for identifying hyperelastic constitutive parameters

: In this study, the Virtual Fields Method (VFM) is applied to identify constitutive parameters of hyperelastic models from a heterogeneous test. Digital image correlation (DIC) was used to estimate both displacement and strain fi elds required by the identi fi cation procedure. Two different hyperelastic models were considered: the Mooney model and the Ogden model. Applying the VFM to the Mooney model leads to a linear system which involves the hyperelastic parameters due to the linearity of the stress with respect to these parameters. In the case of the Ogden model, the stress is a nonlinear function of the hyperelastic param- eters and a suitable procedure shall be used to determine virtual fi elds leading to the best identi fi cation. This complicates the identi fi cation procedure and affects its robustness. This is the reason why the sensitivity based virtual fi eld approach recently proposed in case of anisotropic plasticity by Marek et al. (2017) has been successfully implemented to be applied in case of hyperelasticity. Results obtained clearly highlight the bene fi ts of such an inverse identi fi cation approach in case of non-linear systems.