II. How To Use ATILA

6.2 Underwater Cymbal (1)
GEOMETRY/DRAWING MATERIAL ASSIGNMENT


PROBLEM - Cymbal 12 mm f x 2.4 mm t (Metal thickness 0.2 mm, PZT thickness 0.5 mm x two layer, Cavity hight 0.5 mm); 2D Axisymmetric with a full portion

  • New underwater transducer
  • Learn how to enhance the displacement/effective d coefficient
  • Learn the underwater sound propagation- Monopole & Dipole

GEOMETRY/DRAWING

This is the same cymbal geometry as in the section 3.4 Cymbal.

Create PZT Surface
Geometry -> Create -> Object -> Rectangle -> Enter First and Second Corner Points -> (0,0) ; (0.5,6)
Divide Surface
Geometry -> Edit -> Divide -> Surface -> Near point -> Select Surface to Divide -> Choose NURBS sense -> USense -> Near point (0,4.5)

Create Metal Endcap
Geometry -> Create -> Line -> Enter Points -> (1.2,0) ; (1.2,1.5) ; (0.7, 4.5) ; (0.7, 6)
Copy Lines
Utilities -> Copy -> Lines -> Translation -> First point (0.2,0,0) to Second point (0,0,0) ; Do Extrude -> Select Lines -> Finish

Create Surfaces

Geometry -> Create -> NURBS Surface -> Automatic 4 sided lines

Copy Lines
Utilities -> Copy -> Surfaces -> Mirror -> First point (0,0,0); Second point (0,1,0) ; Third point (0,0,1); Do Not Extrude -> Select Surfaces -> Finish

Create Water Area
Geometry -> Create -> Arc -> First, Second and Third points -> 10,0; 0,10; -10,0
Then, Geometry -> Create -> Line

Divide the Water Surface

In order to simplify the meshing in the Water area (small number of mesh), we will use the water surface area division technique.

Geometry -> Edit -> Divide -> Num Divisions -> Select line (water boundary) -> Num Divisions 10
Then, Geometry -> Create -> Line
Geometry -> Create -> NUEBS surface -> Automatic -> 4-sided lines

MATERIAL ASSIGMENT
Piezoelectric Materials

Data -> Materials -> Piezoelectric -> PZT4 -> Assign -> Pick Surface

Elastic Materials

Data -> Materials -> Elastic -> Brass-> Assign -> Pick Surface

Fluid Materials

Data -> Materials -> Fluid -> Water-> Assign -> Pick Surface

Click Draw -> All materials -> Check the material are assigned as PZT4, Brass and Water

  • Note that because we will discuss both symmetic and asymmetric (Homework 9) modes, the whole part is required for the simulation.