Composite Materials Research Progress

264 Yasuhide Shindo and Fumio Narita
Strain,� zz (�10 -6 )
200
100
0
-100
-200
L = 30 m m
W = 10 m m
4h = 20 m m
a = 20 m m
Test
FEA
x = 5.0 m m
y = 5.0 m m
z = 0.8 m m
W ork
Energy density
-0.3 -0.2 -0.1 0 0.1 0.2
Electric field, E0 (M V/m )
Figure 2. Strain versus electric field for laminated actuator.
E = -0.34 M V/m
0
W ork
Energy density
Poling
o
90 switching
o
180 switching
Figure 3. Polarization switching zone induced by electric field for laminated actuator.
Fig. 3 shows the 180 ◦ and 90 ◦ switching zones near the electrode tip of the actuator under
E0 = −0.34 MV/m. Predictions by different criteria are presented. 90 ◦ switching zone
based on energy density are larger than that based on work. Fig. 4 displays the distribution
of the normal component of stress σzz as a function of x at y =0mm and z =0, 1 and
9 mm for laminated actuator with L = 30 mm, W = 10 mm, 4h =20mm and a =20
mm under E0 =0.2 MV/m from the finite element analysis. The solid line represents the