Accession Number : ADA311237

Title :   Material Parameters for Electrostriction.

Descriptive Note : Technical rept.,

Corporate Author : WISCONSIN UNIV-MADISON DEPT OF CHEMICAL ENGINEERING

Personal Author(s) : Shkel, Yuri M. ; Klingenberg, Daniel J.

PDF Url : ADA311237

Report Date : 11 JUL 1996

Pagination or Media Count : 14

Abstract : Electrostriction is often described by a phenomenological tensor relating a material's deformation to an applied electric field. However, this tensor is not a material parameter; for deformable, weakly compressible materials (e.g., elastomers), the field-induced deformations depend strongly upon boundary conditions. A different approach that relates the deformation to material properties as well as boundary conditions is required. In this paper, we describe a linear theory which introduces five material parameters governing electrostriction: the relative dielectric constant, eD, two derivatives of the dielectric constant tensor, a1 and a2, Young's modulus, Ey and Poisson's ratio, v. Knowledge of these parameters and appropriate boundary conditions allow one to predict field-induced deformations for arbitrary configurations. We demonstrate an experimental procedure for measuring deformations and permittivity changes, from which the parameters a1 and a2 may be extracted (eO, V, and Ey can be measured by a variety of established methods). The linear theory reproduces experimental results for two polyurethane films at small to moderate electric field strengths. We find that the electrostatic force associated with the parameters a1 and a2 is at least ten times larger than the Coulombic attractive force between the electrodes.

Descriptors :   *PARAMETERS, *DEFORMATION, *ELECTROSTRICTION, MEASUREMENT, MATERIALS, THEORY, MODULUS OF ELASTICITY, FILMS, ELASTOMERS, ELECTRIC FIELDS, BOUNDARIES, DIELECTRIC PROPERTIES, COMPRESSIBLE FLOW, ELECTRODES, CONSTANTS, LINEARITY, TENSORS, POLYURETHANE RESINS, ELECTROSTATICS, FIELD INTENSITY, POISSON RATIO.

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE