Uniaxial Electro-Mechanically Coupled Cyclic Deformation of VHB 4905 Dielectric Elastomer: Experiment and Constitutive Model

In the uniaxial deformation mode, the electro-mechanically coupled cyclic deformation of VHB 4905 dielectric elastomer (DE) is systematically studied by the experimental observation and constitutive modeling. From a series of uniaxial electro-mechanically coupled cyclic tests, it is found that with applying a constant voltage, the cyclic softening and ratchetting of VHB 4905 DE are more apparent than that without applying any voltage, which indicate that the VHB 4905 DE exhibits an electro-mechanically coupled effect. Also, the uniaxial electro-mechanically coupled cyclic deformation of VHB 4905 DE presents a strong rate-dependence and remarkable stress-level-dependence. Based on the experimental results, an electro-mechanically coupled visco-hyperelastic constitutive model is proposed by considering the remarkable nonlinear viscosity of VHB 4905 DE and the effect of applied voltage on the cyclic deformation. Comparing the predicted results with correspondent experimental data, it is concluded that the proposed constitutive model reasonably reproduces the uniaxial electro-mechanically coupled cyclic deformation of VHB 4905 DE, including the cyclic softening and ratchetting.