Maxwell stress of a dielectric elastomer subjected to electric field

Hello everyone,

As reported in some references, Maxwell stress of a dielectric  elastomer subjected to electric field can be determined by the following formula

P=e*E^2    (1) -------e=e0*e1, e0 is the dielectric permittivity of vacuum, e1 is the relative dielectric permittivity of the elastomer, and E is the applied electric field.