Experimental study on pure-shear-like cyclic deformation of VHB 4910 dielectric elastomer

Abstract

The cyclic deformation of VHB 4910 dielectric elastomer is experimentally investigated by performing a series of strain-controlled and stress-controlled pure-shear-like cyclic tests at room temperature. In the strain-controlled cyclic tests, obvious Mullins effect is observed in the first cycle, and continuous stress softening is characterized in the subsequent cycles; the Mullins effect and continuous stress softening are intensified by prescribing larger peak strains and higher strain rates. In the stress-controlled cyclic tests, remarkable ratchetting takes place, and its evolution becomes more significant if higher stress levels, lower stress rates and longer hold time at peak stress are prescribed. Moreover, a partial recovery of residual strain indicates that, besides obvious hyper-elasticity, the VHB 4910 dielectric elastomer also exhibits both recoverable viscoelasticity and measurable irrecoverable visco-plasticity during the cyclic tests.