from - http://www.stormingmedia.us/73/7321/A732113.htmlAbstract: 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.
from - http://ses.confex.com/ses/2004tm/techprogram/P1584.HTMThe application of an electric field to any material can displace charge and lead to field-induced elastic strain. If the sign of the strain is unchanged on reversal of the electric field, this property is termed electrostriction and it occurs in all materials whether crystalline or not. The term electrostrictive polymer is used in this study to describe the stress and strain response of a polymer subjected to an electric field. Electostriction is distinguished from piezoelectric behaviour in that the response is proportional to the square of the electric field rather than proportional to the field. The dielectric and mechanical properties of the polymer material determine the magnitude of the stress and strain response. In this study, thin films of dielectric polymers are considered with compliant electrodes. When a charge is placed on the electrodes the polymer film is compressed and its area is increased since the electrodes are compliant. It is assumed that the polymer is hyperelastic, consequently electrical energy is converted to strain energy of the polymer and a concept of compression efficiency is introduced.
Electrostriction is the phenomenon in which a material changes its shape or size when subjected to an electric field. This is due to the reorientation of electric dipoles within the material, causing a change in its physical dimensions.
Electrostriction is used in various technologies such as sensors, actuators, and transducers. It is also utilized in medical devices, energy harvesting, and energy storage systems.
Electrostriction offers several advantages, including high sensitivity, fast response time, and low power consumption. It also allows for precise control and manipulation of material properties, making it useful in a wide range of applications.
Some common materials that exhibit electrostriction include piezoelectric materials, ferroelectric materials, and magnetostrictive materials. Examples of these materials include quartz, PZT, and Terfenol-D.
One potential drawback of electrostriction is that it may result in mechanical fatigue and degradation of the material over time. It may also require a high voltage to achieve significant changes in shape or size, which can be a safety concern in certain applications.