BOUNDARY
CONDITIONS
Polarization/Local
Axes
High voltage should be applied on the
center surface of the PZT two layers, and Ground on the metal
side surface. Choose the polarization direction along the
electric field direction.
Data -> Conditions -> Surfaces -> Geometry -> Polarization
(Cartesian) -> Define Polarization (P1) (1,0) direction
Choose 3PointsXZ -> Center (0,0,0) -> Define X axis
by putting (0,1,0) -> Then define Z axis by putting (1,0,0)
-> Escape
Assign Polarization (Local-Axes P1) -> Choose the PZT surface
-> Finish
Potential
Data -> Conditions -> Lines -> Potential 0.0 (or
Ground in ATILA 5.2.4 or higher version) -> Assign the right-side
line of the PZT -> Forced Potential 1.0 -> Assign
the left-side line of the PZT (which is the center surface
of the two PZT plates)
Surface
Contraints (1/2 part of the whole Cymbal)
We use only 1/2 part of the whole Langevin
transducer, taking into account the symmetry; the left-side
line of the PZT and water should be clamped (X component
is clamped)
The bottom
axisymmetric line of the
whole system (including water) - Y component is clamped.
The axisymmetric axis is taken along x axis (This is the
rule in ATILA).
Data -> Conditions -> Lines -> Line Constraints
-> X components -> Clamped -> Assign the left-side
PZT and Water lines
Similarly, on the Axisymmetric X axis
-> Line
Contstraints -> Y & Z components -> Clamped -> Assign
Radiation
Boundary
Data -> Conditions -> Lines -> Line Constraints -> X
components -> Clamped -> Assign the left-side PZT and
Water lines
Radiation boundary is applied not to
reflect the water-propagating sound at this boundary (like
an anechoic wall). In this sense, the radius of this water
boundary is not essential.
To check the assignment -> Draw -> All
conditions -> Include local axes
MESHING 
Mapped Mesh
Meshing -> Structured -> Surfaces -> Select
all Surfaces -> Then Cancel the further process
Meshing -> Structured -> Lines -> Enter number to divide
line -> Choose "1,
2, 4" for
the lines -> Generate