Dielectric elastomer actuators under equal-biaxial forces, uniaxial forces, and uniaxial constraint of stiff fibers

A membrane of a dielectric elastomer deforms when a voltage is applied through its thickness. The achievable voltage-induced deformation is strongly affected by how mechanical loads are applied. Large voltage-induced deformation has been demonstrated for a membrane under equal-biaxial forces, but only small voltage-induced deformation has been observed for a membrane under a uniaxial force. This difference is interpreted here theoretically. The theory also predicts that, when the deformation of a membrane is constrained in one direction, a voltage applied through the thickness of the membrane can cause it to deform substantially in the other direction. Experiments are performed on membranes under equal-biaxial forces and uniaxial forces, as well as on fiber-constrained membranes of two types: a dielectric elastomer membrane with carbon fibers on both faces, and two dielectric elastomer membranes sandwiching nylon fibers. The experimental observations are compared with the theory.

Tongqing Lu, Jiangshui Huang, Christa Jordi, Gabor Kovacs, Rui Huang, David R. Clarke, Zhigang Suo. Dielectric elastomer actuators under equal-biaxial forces, uniaxial forces, and uniaxial constraint of stiff fibers. Soft Matter. DOI: 10.1039/c2sm25692d