Stability analysis of dielectric elastomer film actuator

Abstract

Dielectric elastomer (DE) is the most promising electroactive polymer material for smart actuators. When a piece of DE film is sandwiched between two compliant electrodes with a high electric field, due to the electrostatic force between the two electrodes, the film expands in-plane and contracts out-of-plane so that its thickness becomes thinner. The thinner thickness results in a higher electric field which inversely squeezes the film again. When the electric field exceeds the critical value, the dielectric field breaks down and the actuator becomes invalid. An elastic strain energy function with two material constants is used to analyze the stability of the dielectric elastomer actuator based on the nonlinear electromechanical field theory. The result shows that the actuator improves its stability as the ratio k of the material constants increases, which can be applied to design of actuators. Finally, this method is extended to study the stability of dielectric elastomers with elastic strain energy functions containing three and more material constants. dielectric elastomer, actuator, electroactive polymer, stability, elastic strain energy function

Effect of mechanical force field on the electromechanical stability of dielectric elastomers

“…Recent years have seen extensive and in-depth studies of the stability analysis of dielectric elastomer . When a voltage is applied on the dielectric elastomer film, the voltage will cause the film to become thinner [6][7][8][9][10][11][12][13][14][15][16][29][30][31][32][33][34][35][36][37][38]. As a result, the same voltage will induce a higher electric field and further cause the dielectric elastomer film to become thinner.…”

“…We have 11 U  22 U , and inserting it into eqs. (10)-(13), we get: Clearly, the results coincide well with Suo's conclusion [1].…”

The constitutive relation of silicone rubber soft active materials

“…The free energy function can be decomposed as follows [26][27][28][29][30][31][32][33][34]: σ , 2 σ , 3 σ of the electromechanical coupling system of the dielectric elastomer is:…”

Analysis of electromechanical stability on dielectric elastomer actuators under large deformations condition

“…O is the stretch ratio of the dielectric elastomer thickness direction, are the original dimension of dielectric elastomers, denote the pre-stretch forces, subject to mechanical forces in three directions, and to electrical voltage U via an external circuit, the deforms to . 1 2 3 , , l l l 1 2 3 , , P P P 1 2 3 , , P P P The free energy function of the DE electromechanical coupling system can be written as follows [27][28][29][30][31][32][33][34][35][36][37][38][39]:…”

“…When the electric field reaches the breakdown electric field, the dielectric elastomers will be breakdown. This is called electromechanical instability or pull-in instability which is the main reason of preventing dielectric elastomers to be used in practical applications [27][28][29][30][31][32][33][34][35][36][37][38][39].…”