# Thread: Linear elastic -> Hyperelastic coefficient conversion

1. Junior Member
Join Date
2009-05
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3

## Linear elastic -> Hyperelastic coefficient conversion

Hello,

I am currently working on modeling soft tissue. I got as only data the Young modulus E=2500 Pa and the poisson ration =0.499 (incompressible material).

They ask me to work with the hyperelastic model so I need to understand if the is an equivalence between hyperelastic and linear elastic coefficient. I will be working with Mooney rivlin model so I need C_10 and C_01.
Can someone help me?

Regards
David

2. If all you know are E and nu (and you cannot perform additional tests), then you should not use a Mooney-Rivin model but a Neo-Hookean model.

The shear modulus for the NH model is E/3.

-Jorgen

3. Junior Member
Join Date
2009-05
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3
Originally Posted by Jorgen
If all you know are E and nu (and you cannot perform additional tests), then you should not use a Mooney-Rivin model but a Neo-Hookean model.

The shear modulus for the NH model is E/3.

-Jorgen
Thank you very much for this answer. Is there a paper/book where I can get this information in order to cite it?

David

4. You can site me

It is actually easy to derive (perhaps you don't need to cite it):

The Poisson't ratio of most rubbers and soft tissues is typically close to 0.5 (that is incompressible).

The shear modulus is given by (see most intro to solid mechanics books):
mu = E / (2 * (1 + nu))

If you insert nu=0.5 you will get mu = E/3...

-Jorgen

5. Junior Member
Join Date
2010-08
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1
What is the incompressibility parameter used in Neo-Hooken model ? how to derive it?

6. Junior Member
Join Date
2011-10
Posts
5
Hello Dr. Jorgen

As i told you, I have hardness value for rubber and nu = 0.5(rubber is incompressible). You asked me use Neo-Hookean form. I needed two parameters C10 and D1

So I converted hardness 's' into E as per ref formula E = 0.0981(56+7.62336s)/0.137505(254-2.54s)

I will get Shear modulus µ0 = E/2(1+nu). and from this i will calculate C10 = µ0/2

D1 = 0 for incompressible in abaqus/standard,

So I will have both C10 and D1

please tell me if this approach is right....

Last edited by sandeep18784; 2011-10-08 at 18:01.

7. That sounds right.

-Jorgen

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