Effect of different prestretching index and preloading on actuation behaviors of dielectric elastomer actuator

Herein, the prestretching indexes of dielectric elastomers (DE) were determined by measuring the tensile properties, and then the actuation displacement and output force of the conical dielectric elastomer actuator (CDEA) with different prestretching index and different preloading were discussed in detail, finally, the three indexes of thickness, generatrix and circumferential stretch are proposed to calculate the strain energy density of the CDEA. The experimental results show that the large prestretching ratio will cause the obvious instability of DE. Two materials showed obvious thin neck phenomenon and finally fracture. The stress-strain curve of DE shows hysteresis phenomenon under cyclic loading, and with the increase of cycle times, the unit stress and the unit hysteresis loss rate both decrease, and the change range is larger. When the prestretching of outer domain is the same, the displacement and force of CDEA increase with the increase of voltage, and the displacement curve appears parallel distribution under different voltage. The Gent model can better reflect the nonlinear deformation behavior of CDEA. This study provides valuable guidance for the design of high performance DEA and the application of dynamic DEA. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study determined the prestretching indexes of dielectric elastomers through measuring tensile properties and discussed the actuation displacement and output force of the conical dielectric elastomer actuator with different prestretching index and preloading conditions. The study proposed three indexes to calculate the strain energy density of the actuator and found that a large prestretching ratio could cause instability in the dielectric elastomers. The Gent model was identified as better reflecting the nonlinear deformation behavior of the actuator.