Variation: Prestretch

The prestretch of the membrane is a very important parameter to influence the performance of dielectric elastomer actuators. When the dielectric membrane is prestretched, it decreases in thickness. Since the size of the Maxwell stress is determined by the electric field across the membrane (see Modeling section), smaller voltages are required to obtain the same Maxwell stress when the membrane is prestretched.

The more important influence of the prestretch on the actuation performance is that it moves the occurrence of electromechanical instability (see Modeling section) to larger strains or even completely removes it, so that larger strains are possible before failure.

The following figures show the results of a study that investigates the effect of prestretch on the performance of circular dielectric elastomer actuators:

Prestretch 3x3

Prestretch 4x4

Prestretch 5x5

(Strain after 900s as function of voltage for different prestrains)