Electromechanical deformation of dielectric elastomer in two types of pre-stretch

A pre-stretched dielectric elastomer is capable of large deformation, when subject to voltage. This paper investigates the effect of two types of pre-stretch: by strain and by stress. The difference is compared and discussed using thermodynamics models. The significance of the pre-stretch in actuation is explained by examining the true stress in actuation. Under both pre-stretch strategies, during the actuation, the dielectric elastomer exhibits hysteresis loops due to snap-through but differs in shape and physical quantity. With pre-stretch by strain, the dielectric elastomer features a discontinuous snap in stretch while with the stress the voltage snaps.