Mooney Rivlin constants

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1

Dear sir,
Hi every one , I have tried to solve hyper elastic problem , But i don’t know how to find Mooney revlin constants , and bulk modulus but i have uni axial tensile data for rubber material .

2

Hi @venkatesan,

With the uniaxial data it’s possible to determine the Mooney-Rivlin constants - could you share your uniaxial data here? We actually have a script where we can quickly get these values for you :smile:

Best,
Anna

1 Like
3

Hi,
Sorry for late response,i have the file is in excel format , but i could not attach here because it asks jpeg format.

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4

@venkatesan, you can attach a shared google spreadsheet or email me the excel file - aflessner@simscale.com

Best,
Anna

5

Hey @venkatesan!

Here you go with all the hyperelastic curve fitting constants:

Neo-Hookean:

C10: 2754572.269

NH.png2400×1427 145 KB

Mooney Rivlin:

C01: -1543725.306, C10: 3478878.725

MR.png2400×1427 149 KB

Signorini:

C01: -4325191.035, C10: 5952426.9831, C20: -97843.705

SIG.png2400×1427 139 KB

I would prefer to use Signorini as the fit is quite accurate, may be not for lower strains but later for higher strains. Please also ignore the added 1 in strain values. This is normally done in order to get the results at zero or low strain. Please see Hyperelastic material documentation for more info.

Can you also please tell us about this material? It will help other users to use this data in case they are looking for same material type.

I hope this help. If you need anything further, do let us know. We will be glad to help. :smile:

Best,
Ahmed.

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6

@venkatesan! One more thing. I looked in to your case and it seems like there is a wrong face definition among solids. This could be due missing pre-definition of these faces prior to mesh upload. Please have a look in the figure below:

mesh_face_definition_problem.png1354×766 33.3 KB

This is just to notify you since it may lead to either failed simulation or wrong results if some boundary condition on these faces is applied.

Best,
Ahmed

7

Hi

How to calculate mooney rivlin constants using excel curve fitting method. If you have any sheet please share with me.

Thank you

8

Hi @duraisamy!

For a Mooney-Rivlin curve fit you could simply use a commercial software like MATLAB or find a pre-defined Excel Sheet for such applications online (or use the built in function from Excel itself to find a fitting curve). If you use MATLAB I can provide you with a script (think I have one using 3 different methods to fit data).

Cheers!

Jousef

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9

Thank you

Please provide a script

10

Could you please share the script? Thanks!

11

Hi @mpolo!

I currently cannot find the script and it is somewhere on my other laptop. I would suggest just looking for standard scripts you can find online or look for explanations on Stackoverflow :slight_smile:

All the best!

Jousef

12

Hello jousefm,

Could you share with me the script, too?
Thank you.

13

Hi @robinsonferrar!

Have to dig deep into my hard drive to find it :smiley: Do you need it fast? Will probably do a quick video on 3-4 ways on how you can easily interpolate given data sets if you like.

Jousef

14

Hi Jousefm,
I can wait for the video and if you find it you send to me.
Thank you so much.

Robinson

15

Will record it once I have a bit of free time Robinson, keeping you updated :slight_smile:

Jousef