Equivalent conductance and impedance Answered

Sneha

May 31, 2023 14:27

Hello..After simulation, i got four conductance values corresponding to the four applied terminal voltage.How can i get single equivalent conductance value when I applied four terminals(+ve voltage) parallel in a device.

16 comments

Tapiwa Mutasa
June 05, 2023 19:26

You can make the terminals into a single electrode and use this electrode as the source for your impedance calculation. You will need to do this in analyst mode.

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Sneha
June 06, 2023 00:10

Thank you for your response. I would like to know that is there any way to solve it in designer mode? ie, how can i get equivalent conductance and impedance values when i connected four parallel terminals and ground in the interface of four pzt rings.

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Tapiwa Mutasa
June 06, 2023 16:08

This is not possible to do in Designer. You will have to modify the designer generated script to do this. You can do this by exporting the script from Designer and modifying it by giving the same name to the loads you want to be connected.

I am attaching a designer file and the generated script which i have modified here which you can use as a reference.
Designer File

Modified File

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Sneha
June 06, 2023 17:36

Thank you fir your response. I am using OnScale
in Designer mode only.so i am not able to understand this analyst codes. If i open my
project in analyst mode(OnScale solver), where i have to edit to short all parallel terminals and ground?

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Tapiwa Mutasa
June 06, 2023 19:25

You need to look at the piez command. This will be in line 546 of the Modified file that I sent earlier. You can compare this piez command to one in the file you export to see the differences. You can also refer to the command reference.

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Sneha
June 07, 2023 00:32

Sorry..i am not able to open the designer and modified files that you have sent.

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Tapiwa Mutasa
June 07, 2023 13:55

Designer File

Modified File

Please try these links.

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Sneha
June 08, 2023 05:55

Ok..thanks alot

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Sneha
June 08, 2023 06:00

I would like to know that,If i simulate a device (3D) under water at 150 kHz Frequency in OnScale designer mode, what will be the size of water geometry? I roughly added water size of 1lamda(lamda=c/f=1500/150=10mm) on each side.

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Sneha
June 08, 2023 06:02

And is there any way to find out Receiving sensitivity directly from OnScale ?

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Tapiwa Mutasa

June 08, 2023 12:50

The model is defined by you, so you should know what the size of the water geometry is. With regards to sensitivity, you will have to calculate this yourself according to a metric of your choosing. Review has some tools for scripted calculation. OnScale can produce all the necessary outputs required to calculate this.

For example this script for calculating impedance and TVR.

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

c

c TVR / OCV CALCULATION

c

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




mp omp * *




c Inputs

text fname = 'insert_filename_here' /* enter history file name (without extention)

symb radius = 1. /* tVR distance

symb fbeg = 0 /* beginning plotting frequency

symb fend = 10.e3 /* ending plotting frequency




c Read time history

read f1 '$fname.flxhst'           /* read in time history




grph type standard /* use old graphics to plot using the frequecy range




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

c

c EXTRAPOLATION

c

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




extr

      data '$fname.flxext'      /* read in extrapolation data

      file f2 cler         /* name output file

      spot 0. $radius 0.

      calc 1                    /* calculate 

      end




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

c

c MANIPULATE DATA - TIME TO FREQUENCY

c

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




freq

     file f3

     time pad 5

     fft f2 1                /* fft of extrapolated pressure

     fft f1 2                /* fft of input voltage

impd f1 1 f1 3/* impedance

     end







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

c

c CALCULATE TVR

c

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




make

      file f4

      curv { f3 1 } / { f3 3 }                  /* normalise pressure response

      curv ( 20. * alog10 ( { f4 1 } / 1.e-6 ) ) + ( 20. * alog10 ( ( $radius ) ) )       /* convert to TVR

  curv 20. * alog10 ( { f3 5 } ) + { f4 2 }/* TCR

  curv { f4 3 } - 354. - 20. * alog10 ( { freq } / 1.e3 )

      end










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

c

c PLOT

c

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




c Plot impedance

grph

     nvew 1

     ttl 1

Electrical Impedance

     pset sttl 1 'Impedance Magnitude'

     pset ylab 'Impedance (Ohms)'

     plot f3 5

     set wndo $fbeg $fend

set log y on

imag

     end




term




c Plot TVR

grph

     nvew 1

     ttl 1

TVR

     pset sttl 1 'TVR from Extrapolation'

     pset ylab 'TVR dB re uPa/V at 1m'

     plot f4 2

     set wndo $fbeg $fend

set log x on

imag

     end




term




c Plot OVC

grph

     nvew 1

     ttl 1

OCV

     pset sttl 1 'OCV from Extrapolation'

     pset ylab 'OCV dB re V/uPa at 1m'

     plot f4 4

     set wndo $fbeg $fend

set log x on

imag

     end




term




c Write to file

grph

plot f3 5 f4 2 f4 4

writ onex 'tvr_ovc.txt'

end




stop

Sneha
June 08, 2023 13:01

Thank you very much.

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Sneha
June 08, 2023 13:21

I have one more doubt please. I am not able to fix the damping values( bulk and shear attenuation) of damping materials which i have used in my projects.so i would like to know that the formula or method which is used for finding frequency dependent attenuation of various materials.i tried damping tool to fix the losses. But i didn't get the idea regarding how to choose bulk and shear losses. Bulk velocity, shear velocity and density etc got from the material conversion tool and from literature's. Because of incomplete material properties, the simulated results have variations from experimental results.

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Tapiwa Mutasa
June 09, 2023 13:43

You can have a look at this article for more information on the damping models in OnScale Lab.

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Sneha
June 10, 2023 08:35

Thank you.I read this one. But i didn't get the idea of choosing damping values of material.

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Sneha
June 13, 2023 17:49

Hello..would you please provide me the viscoelastic bulk and shear attenuation of the material, it's properties are given here. density= 1.8e+3 Kg/m^3.
Poissions ratio= 0.37
Youngs modulus=1e+10 N/m^2
Bulk modulus=3.5714e+10 N/m^2 at 1MHz
Since i am not able to find out these attenuation values, the simulated results from OnScale shows some variations from experimental results.

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