The electric field may be written as − E$_{x}$ = a$_{11}$P$_{x}$ + d$_{15}$γ$_{xz}$ + f$_{1111}$u$_{xx}$ + f$_{1331}$ ( u$_{xx}$ + w$_{xz}$ ) + f$_{3311}$w$_{31}$ − E$_{z}$ = a$_{33}$P$_{z}$ + d$_{31}$u$_{x}$ + f$_{1133}$u$_{xz}$ + f$_{1313}$ ( u$_{31}$ + w$_{11}$ ) + f$_{3333}$w$_{zz}$. P$_{x}$ = − 1 a$_{11}$ ( ϕ ′ x − d$_{15}$ ( u$_{z}$ + w$_{x}$ ) − f$_{1111}$u$_{xx}$ − f$_{1331}$ ( u$_{xx}$ + w$_{xz}$ ) − f$_{3311}$w$_{31}$ ) P$_{z}$ = 1 a$_{33}$ ( ϕ ′ z − d$_{31}$u$_{x}$ − f$_{1133}$u$_{xz}$ − f$_{1313}$ ( u$_{31}$ + w$_{11}$ ) − f$_{3333}$w$_{zz}$ ) . H = 1 2 a$_{11}$P 2 x + 1 2 a$_{33}$P 2 z + 1 2 c$_{11}$ε 2 x + 1 2 c$_{33}$ε 2 z + 1 2 c$_{55}$γ 2 xz + c$_{13}$ε$_{x}$ε$_{y}$ + d$_{15}$γ$_{xz}$P$_{x}$ + d$_{31}$ε$_{x}$P$_{z}$ + P$_{1}$ ( f$_{1111}$u$_{xx}$ + F$_{1331}$ ( u$_{zz}$ + w$_{xz}$ ) + f$_{3311}$w$_{xz}$ ) + P$_{3}$ ( f$_{1133}$u$_{xz}$ + f$_{1313}$ ( u$_{xz}$ + w$_{xx}$ + f$_{3333}$w$_{zz}$ ) − 1 2 ε$_{0}$ ( ϕ ′ $_{x}$) 2 − 1 2 ε$_{0}$ ( ϕ ′ $_{z}$) 2 + ϕ ′ $_{x}$P$_{x}$ + ϕ ′ $_{z}$P$_{z}$ = 1 2 a$_{11}$ ( ϕ ′ x − d$_{15}$ ( u$_{z}$ + w$_{x}$ ) − f$_{1111}$u$_{xx}$ − f$_{1331}$ ( u$_{zz}$ + w$_{xz}$ ) − f$_{3311}$w$_{xz}$ ) 2 + 1 2 a$_{33}$ ( ϕ ′ z − d$_{31}$u$_{x}$ − f$_{1133}$u$_{xz}$ − f$_{1313}$ ( u$_{zz}$ + w$_{xx}$ ) − f$_{3333}$w$_{zz}$ ) 2 + 1 2 c$_{11}$u 2 x + 1 2 c$_{33}$w 2 z + 1 2 c$_{55}$ ( u$_{z}$ + w$_{x}$ ) 2 + c$_{13}$u$_{x}$w$_{z}$ + 1 a$_{11}$ ( ϕ ′ x − d$_{15}$ ( u$_{z}$ + w$_{x}$ ) − f$_{1111}$u$_{xx}$ − f$_{1331}$ ( u$_{zz}$ + w$_{xz}$ ) − f$_{3311}$w$_{xz}$ ) · ( ϕ ′ x + d$_{15}$ ( u$_{z}$ + w$_{x}$ ) + f$_{1111}$u$_{xx}$ + f$_{1331}$ ( u$_{zz}$ + w$_{xz}$ ) + f$_{3311}$w$_{xz}$ ) + 1 2 a$_{33}$ ( ϕ ′ z − d$_{31}$u$_{x}$ − f$_{1133}$u$_{xz}$ − f$_{1313}$ ( u$_{zz}$ + w$_{xx}$ ) − f$_{3333}$w$_{zz}$ ) · ( ϕ ′ z + d$_{31}$u$_{x}$ + f$_{1133}$u$_{xz}$ + f$_{1313}$ ( u$_{zz}$ + w$_{xx}$ ) + f$_{3333}$w$_{zz}$ ) − 1 2 ε$_{0}$ ( ϕ ′ $_{x}$) 2 − 1 2 ε$_{0}$ ( ϕ ′ $_{z}$) 2 T$_{k}$ = 1 2 ∫ V b ϱ [ ˙ u 2 + ˙ w $^{2}$] dV$_{b}$ W$_{d}$ = ∫ l 0 ( pu + qw ) dx, Now, the polarization may be expressed as In this case, the equation (3) takes the form The kinetic energy is The work done is 12