II. How To Use ATILA

6.3 Tonpilz Sonar (5)
VIEW RESULTS


PROBLEM - Tonpilz Transducer under Water, Axisymmetry, PZT8, Steel and Aluminum


From the Calculate menu, select Calculate. During the computation, use the Calculate Window, as well as View Process Info commands in order to monitor the progression of the computation. The amount of information printed in the Calculate Window is controlled by the Printing setting (Problem Data section).
When the computation is finished, GiD displays the following message.

POST PROCESS/VIEW RESULTS

Click for Opening the Post Calculation (Flavia) Domain
Click Admittance/Impedance Result

Note that the admittance is given without correction for the model symmetry. The magnitude of the admittance should be multiplied by 2π. This is easily done by using the comma separated value (CSV) files located in the working directory. Use Open Shell from the ATILA menu to access the working directory.

Note that wather load shift the transducer resonance frequency lower and provides significant damping.

 

Calculation under Air

Calculation under Water

View Animation - Vibration Mode at a Particular Frequency

View results -> Default Analysis/Step -> Harmonic-Magnitude -> Set a Frequency
(Peak Point : 32900 Hz for the Resonance Mode)
Double Click Loading frequency: 32900 Hz Harmonic Case -> Click OK (Single Click and Wait for a while!)

A message confirms the frequency and case that you are preparing for animation:

Set Deformation -> Displacement

View results -> Deformation -> Displacement

Other parameter than Displacement

Set Results View -> View results -> Contour Fill -> Von Mises Stress
After setting both “Results view” and “Deformation” -> Click to see the Animation

Note that we have superposed the magnitude of the Von Mises Stress on the Real Part of the structure deformation. Note that you may want to change the deformation factor (here it is set to 2·107).

Under Air

Note that the number of frames in the animation is set in the Preferences (ATILA menu).

Pressure Observation

You may also want to display the deformation and the pressure Underwater at the frequency of maximum admittance (32.25kHz).

 

The solid part of the transducers appears disconnected from the water domain. This is normal, since there are no displacements associated with the fluid elements used in this computation. Similarly, the solid part is not colored, since we are plotting pressures, and that there is no pres-sure degree-of-freedom in the elastic and piezoelectric domains.

Transmitted Voltage Response (TVR)

Lastly, we can use the acoustic postprocessing features available. For instance, display the Transmitted Voltage Response (TVR).