Experimental study on pure-shear cyclic deformation of dielectric elastomer at different temperatures

Abstract

A series of pure-shear cyclic tests were performed on VHB™4910 dielectric elastomer at various temperatures, and the investigations were focused on the influence of temperature variations on the cyclic deformation of the elastomer and the influences of loading level and loading rate on the temperature-dependent cyclic deformation. The results demonstrate that the temperature-dependent deformation of VHB™4910 dielectric elastomer primarily manifests its viscoelasticity, while the hyper-elastic part shows comparatively weaker temperature-dependence. At different temperatures, the elastomer exhibits a cyclic softening during the strain-controlled cyclic loading. Both the peak stress and residual strain reduce with increasing the temperature and reach a stable state more rapidly at higher temperatures. A more pronounced temperature-dependence is exhibited in the stress response of the elastomer at a high loading rate; while a lower rate-dependence is observed at a high temperature. The ratchetting of the elastomer presented in the stress-controlled tests becomes more prominent as the temperature increases, but the rate-dependence of ratchetting is weaker at higher temperatures. Moreover, the temperature-dependence of ratchetting is more significant at a high-stress level as compared to that at a low-stress level.