3.1. Modeling
Guillot et al. explained from macroscopic level, that therewas an
empirical relationship between the electrostrictive coefficient, the
dielectric constant and the compliance coefficient [18]. Recently,
Diguet et al. pointed out that the phase separation into HDs with
high dielectric constant and SDs with weak dielectric constant can
result into the strong electrostriction properties of pure segmented
PU. This, in turn, leads to heterogeneities of both elastic and
dielectric constants and to electric field gradients, which makes the
SDs shrink and the whole material compress [9]. In this work,
Diguet's model is extended to take into account morphological
parameters such as the HD diameter, the HD-SD distance and the
HS weight fraction.
The strain is calculated from the Z-component of electric body
force, created by HD taken as a sphere with radius a into the