II. How To Use ATILA

4.1 Rosen Type Transformer (1)
GEOMETRY/DRAWING MATERIAL ASSIGNMENT


PROBLEM - Rosen Transformer 25 mm x 8 mm x 2.2 mm t


GEOMETRY/DRAWING

Analysis of a piezoelectric transformer. The model is 3D, and two analyses will be used: modal, to determine the resonance frequency of the transformer, and harmonic, to determine the gain of the transformer at resonance.

A piezoelectric transformer is a device that operates at resonance and that makes use of both direct and converse piezoelectric effects. In short, a low-voltage signal is applied at the input section in order to excite the mechanical resonance of the transformer. The stresses induced by the resonance effect produce charges at the electrodes of the output section. As a result, the input voltage is transformed, either into a higher (step-up transformer) or lower voltage (step-down transformer).

The transformer modeled in this tutorial is a so-called Rosen-type (from the name of the inventor), and it is somewhat simplified. It operates in a λ/2 (half-wavelength) longitudinal vibration mode. The dimensions used for the geometry are shown (in mm) in the following figure.

There are many ways to define the geometry elements (points, lines, surfaces, and volumes) required for the problem. You have learned already enough information about constructing the geometry.

 

The material se-lected for this problem is PZT4 for both input and output sections. The electrodes are shown in the next figure.

MATERIAL ASSIGMENT
Piezoelectric Materials

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

Assign material PZT4 to the two volumes. Note that the definition of the material PZT4 includes losses. You can verify the loss angles by clicking on the Losses tab. The values Delta_m, Delta_p, and Delta_d correspond to the loss angle for the mechanical, piezoelectric and dielectric tensors, respectively.

When this is done, the material assignment should be similar to the following image (you can obtain this by selecting, on any material window, the option Draw | All materials).

Click Draw -> All materials -> Check the material is assigned as PZT4