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. 2026 May 1;19(9):1864. doi: 10.3390/ma19091864
Latin Letters
B Body force per unit mass (gravitational force)
b Width of the beam
CLN Green deformation tensor
C˙LN Deformation (strain) rate tensor in material coordinates
D Electric displacement vector
d31 Piezoelectric strain coefficient
dij Deformation (strain) rate tensor
dS Surface area element
dV Volume element
E Electric field vector
ELN Green–Lagrange strain tensor (finite deformation)
E˙LN Green–Lagrange strain rate tensor
E~IJ Strain tensor in the linearized theory
e~ij Infinitesimal strain tensor in spatial coordinates
FP Distributed force due to polarization and electric field
FmM Deformation gradient of the forward motion
FIi−1 Deformation gradient of the inverse motion
GM Temperature gradient in material coordinate
h Heat energy source per unit mass
hE Electrostatic energy source
I Second moment of area of the cross-section
J Jacobian
K0 Curvature
L Beam length
mP Distributed couple due to polarization and electric field
M Bending moment
n Outward unit normal vector of the discontinuity surface
P Polarization vector
q Heat flux vector
QI Heat vector in material coordinates
r(h) Successive difference ratio (convergence criterion)
S(t) Surface of the body
t Time
tc Thickness of the aluminum core
tp Thickness of the PZT patch
u Displacement vector
ui Components of the displacement vector
U Relative displacement velocity of the discontinuity surface with respect to the medium
V Applied electric potential
V(t) Volume
v Velocity vector
vi,j Velocity gradient tensor
w(L) Free-tip displacement
wf Free surface charge distribution
wij Spin (whirl) tensor
X Position vector in the undeformed configuration
XM,m Deformation gradient of inverse motion
y Position vector in the deformed configuration
ym,M Deformation gradient
Y Young’s modulus
YI Bending stiffness per unit width
zt,zb Thickness coordinate for the upper and lower patches
Greek Letters
Σijkl Elasticity tensor components in spatial coordinates
μijl Piezoelectric coupling tensor components in spatial coordinates
βil Electric permittivity tensor components in spatial coordinates
ϵij Infinitesimal strain tensor components
ξ0 Permittivity of free space
η Entropy density per unit volume
ε Internal energy per unit volume
θ Temperature
ΠI Polarization vector per unit mass
ρ Mass density in the deformed configuration
ρ0 Mass density in the reference configuration
Σ Thermodynamic stress potential
σij Asymmetric stress tensor components
σ¯ij Symmetric stress tensor components
σy Peel stress
τxy Interface shear stress
φ Electric potential
ψ Helmholtz free energy density/thermodynamic potential
Γ Discontinuity surface
ωk Angular velocity components
Special Notation
δij Kronecker delta
εijk Permutation tensor
∇ Gradient operator
(⋅)i Derivative with respect to variable i
⋅ Jump across the discontinuity surface
PATH1 Longitudinal interface path (clamped end → free end)
PATH2 Transverse interface path (along patch width)
Abbreviations
FEM Finite Element Method
PZT Lead–Zirconate–Titanate
DOF Degree of Freedom
APDL ANSYS Parametric Design Language
2D/3D Two-Dimensional/Three-Dimensional