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# Example3Fully Coupled Analysis (Sound Wave Drive)

General

• The drive from the sound wave domain is analyzed. The sound pressure is solved as the floating electrode voltage of the piezoelectric material.

### Analysis Space

 Item Settings Analysis Space 3D Model unit m

### Analysis Conditions

 Item Settings Solvers Piezoelectric Analysis [Rayleigh] Acoustic Analysis [Mach] Analysis Type Harmonic analysis Options Select “Fully coupled analysis”

The harmonic analysis tab is set up as follows.

The sound waves propagate outside the analysis domain. Therefore the “open boundary” condition below is applied initially.

 Tab Setting Item Setting Harmonic Analysis Frequency 10×10^3[Hz] Sweep Type Single frequency Open Boundary Tab Type Absorbing boundary Order of Absorbing Boundary 1st degree Coordinates of Origin x = y = z = 0

### Graphical Objects

Piezoelectric materials are placed around the respiratory sphere used in the Exercise 4. The sound pressure is measured. 5 semicircle piezoelectric materials are placed around the respiratory sphere for measurement. As shown below, one piezoelectric material has ground and floating electrode. The pressure is detected by the voltage of the floating electrode.

### Body Attributes and Materials

 Body Number/Type Body Attribute Name Material Name 4/Solid Air 000_Air(*) 5/Solid Piezoelectric material_000 000_P-4 * 6/Solid Piezoelectric material_045 000_P-4 * 7/Solid Piezoelectric material_090 000_P-4 * 8/Solid Piezoelectric material_135 000_P-4 * 9/Soid Piezoelectric material_180 000_P-4 *

* Available from the Material DB

### Boundary Conditions

 Boundary Condition Name/Topology Tab Boundary Condition Type Settings VEL/Face Acoustic Speed 1[m/s] Open/Face Acoustic Open boundary FIX Mechanical Displacement UX=0, UY=0, UZ=0 UY0 Mechanical Displacement UY=0 V0 Electric Voltage 0[V] FLOAT_000～FLOAT_180 Electric Floating electrode

### Results

The sound pressure distribution is shown as follows. For comparison purpose, the model with piezoelectric materials removed is shown.

Result 1 (a) The sound pressure distribution of the model with piezoelectric materials removed Result 1 (b)The sound pressure distribution of the model including piezoelectric materials (for reference)

The voltage of the floating electrodes are shown on the right side of the figure.

We can observe that the sound waves are obstructed by the piezoelectric materials.

The figure below is the view in the + X direction of the figure above with piezoelectric materials shown. The colors of the semicircles indicate the floating electrode voltages. The numbers on the right side of the piezoelectric materials are the floating electrode voltages.

The respiratory sphere has large sound pressure and the voltage is large in its front. We can consider that the voltage is obtained corresponding to the sound pressure.

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