LAUSR

Abstract An electro-mechanically coupled visco-hyperelastic-plastic constitutive model is established in this work to describe the cyclic deformation of dielectric elastomers (DEs) by addressing the significant ratchetting and cyclic stress-softening behaviors of DEs resulting from the coupled visco-hyperelasticity, plasticity and electro-mechanical effects. First, a visco-hyperelastic-plastic constitutive model is constructed in the framework of large deformation to incorporate the visco-hyperelasticity and plasticity of DEs, simultaneously. The typical Ogden's formulation is employed for the description of basic hyperelastic response; multiple relaxation mechanisms are adopted to capture the time-dependent viscoelastic part; and a finite plastic flow rule based on the arc-length description is proposed to describe the plastic one. Then, within the framework of nonlinear electro-mechanically coupling approach and by assuming quasi-linear dielectric behavior, the visco-hyperelastic-plastic constitutive model is extended to an electro-mechanically coupled one. Finally, the proposed models are, respectively, validated by comparing the predicted results with corresponding experimental ones of VHB™4910 DE. It is found that the pure mechanical and electro-mechanically coupled cyclic deformation of VHB™4910, including the ratchetting and cyclic stress-softening as well as their dependence on the loading level, loading rate and phase-angle difference of cyclic electro-mechanical loading, can be reasonably predicted by the proposed constitutive models.