Modeling mechanical and electromechanical behavior of polymers

This study proposes a hybrid hyperelastic strain-energy formulation for soft elastomers constructed using invariants of both the right Cauchy–Green tensor C and the right stretch tensor U. The model is validated through a two-tier evaluation: (i) benchmarking against diverse experimental datasets from the literature, including rubbers and hydrogels, and (ii) comprehensive in-house mechanical tests conducted on Latex, Oppo, and Ecoflex specimens. To extend the framework to electro-active polymers, the hyperelastic formulation is coupled with an established electro-mechanical free-energy function, and the resulting model is verified using published voltage-deformation data. Despite requiring only three material parameters, the hyperelastic component successfully reproduces strain softening, strain hardening, and diverse deformation modes, whereas the electro-mechanical extension captures voltage-induced actuation with high fidelity. Comparative assessments against established models, including Gent-Gent and micromechanical formulations, highlight the superior accuracy and predictive capability of the proposed framework.