TITLE:
Theoretical Estimation of Stability of Dielectric Elastomers
AUTHORS:
Asha Dahiya, O. P. Thakur
KEYWORDS:
Elastomers; Electromechanical Stability; Energy Convexity; Mechanical Strength; Generalised Variable
JOURNAL NAME:
World Journal of Condensed Matter Physics,
Vol.2 No.4,
November
26,
2012
ABSTRACT: When dielectric elastomers sandwiched between compliant electrodes and high electric voltage is applied to the dielectric elastomers. Then due to the electrostatic force between the electrodes the elastomers expands in plane and contract out of plane so that it becomes thinner. As the thickness decreases we observe the increase in the applied electric voltage with the positive feedback effect. This positive feedback leads the electrical as well as mechanical breakdown of elastomer. By applying a mechanical pre-stretch the mechanical stability of dielectric elastomers gets also increased. In this paper, a new generalized set of strain/stretch variables qrN has been introduced to get the expression for second order elastic moduli for the ideal electro elastic material deformed to orthorhombic structure. The strength of a loaded crystal determined from the new moduli has been compared with the strength of classical (Green, Stretch) moduli. It has been observed that the use of incorrect formula by ignoring shear strain leads to incorrect estimation of stability. This problem has been resolved by considering stretch variable in tensor form as generally observed in the process of electrostriction in the elastomers.