# Using Correct Damping in Model Answered

Hi everyone.

I am simulating ultrasound through Titanium grain structure and to get an accurate representation of how the wave attenuates through the material, I need to consider the damping of the model. However, I am not sure how to select the appropriate values.

c Crystal Stiffness properties

symb c11 = 160e9

symb c12 = 90e9

symb c13 = 66e9

symb c33 = 191.7e9

symb c44 = 46.5e9

symb rho = 4430

c ***********************************************************************************************************

c Titanium Material

c ***********************************************************************************************************

type lean

wvsp off

prop titm $rho

$c11 $c12 $c13 0.0 0.0 0.0 $c11

$c13 0.0 0.0 0.0 $c33 0.0 0.0

0.0 $c44 0.0 0.0 $c44 0.0 $c44

do loopI I 1 $nmat 1

copy titm matr$I

axis matr$I matAx$I

rdmp matr$I $freqdamp db .3 1.2 700000. 1. 0.01

end$ loopI

Where I have included my rdmp line of code. I have no idea how I can implement the proper longitudinal and Shear Q Factor. These values of .0.3 and 1.2 I have just chosen at whim.

And from the command help I need to satisfy a range of options**rdmp **

*matname centfreq option dilatation shear frequency expv distance exps*

Any help would be greatly appreciated.

Thanks

Dave :)

## 1 comment

Chloe AllisonHi Dave,

Getting the damping correct for your model can be tricky. Have a look at this article. We also have MATLAB files that plot the damping model performance for the input settings here.

I hope this helps!

Best Regards,

Chloe

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