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Mooney Rivlin Material Constants

10 Posts
7 Users
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Posts: 2
Topic starter
(@mojtaba)
New Member
Joined: 16 years ago

Hi everybody,

i am new in the field of simulating elastomeres in FEM. I have found some information about how to determine/measure my invariants to fill the mooney rivlin model.

But i still dont understand where i get the C1...C11 from.

My formula:

W= C10(I1-3)+ C1(I2-3)+ C11 (I1-3)(I2-3)+ C20(I1-3)+C30(I1-3)

in the literature it says that i can neglect some coefficients so i get:

W= C10(I1-3)+ C1(I2-3)+ C11 (I1-3)(I2-3)

I read some threads but i couldnt find something that gives me enough information to solve the problem!

Thanks for your help!

dave

Topic Tags
9 Replies
Posts: 124
(@bw_composite)
Estimable Member
Joined: 17 years ago

Ave81,

the constants are determined from experimental data in order to provide the best possible fit.

Ideally data should come from different tests but it might be sufficient to use data related to deformation modes you are about to simulate.

You can use built in functions (there is certainly one in Ansys, I am sure Abaqus or Marc have similar options) or you can implement your own method.

In general you would have to to:

- find the true stress as a function of the unknown constants

- convert everything to true stress and minimize the differences with the measured data

Hope this helps

ATB

Muzialis

Topic Tags
9 Replies
Posts: 2
Topic starter
(@mojtaba)
New Member
Joined: 16 years ago

Thank you for your answer Muzialis!

For me it sounds still a little abstract. Is there any paper or documentation about the analysis you where writing about? Or something like a experimental manual, how to determine those values?

Thanks a lot for any help!

Dave

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Posts: 1
 Don
(@Don)
New Member
Joined: 17 years ago

Mooney

Hi!

Some info related to the Mooney-Rivlin material model are attached in the pdf file.

Good luck, have fun!

David Felhos

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Posts: 124
(@bw_composite)
Estimable Member
Joined: 17 years ago

ave81,

I do not know any source on this specific matter, but I have put a sample calculation in attachment, it might help.

All he Best

Muzialis

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Posts: 25
(@longcar2000)
Eminent Member
Joined: 16 years ago

finding mooney-rivlin constant

take two parameter mooney-rivlin model

parameters are c1 and c2, d. these can be found by using following relation

shear modulus=2(c1+c2)

d=2/k

k=bulk modulus

initially take c2 as zero and increasing the c2 values and find c1 for corresponding c2 values.

E = 3 K (1 - 2v)

E = 2 G (1 + v)

nandish rv

bangalore

[QUOTE=ave81,3109]Hi everybody,

i am new in the field of simulating elastomeres in FEM. I have found some information about how to determine/measure my invariants to fill the mooney rivlin model.

But i still dont understand where i get the C1...C11 from.

My formula:

W= C10(I1-3)+ C1(I2-3)+ C11 (I1-3)(I2-3)+ C20(I1-3)+C30(I1-3)

in the literature it says that i can neglect some coefficients so i get:

W= C10(I1-3)+ C1(I2-3)+ C11 (I1-3)(I2-3)

I read some threads but i couldnt find something that gives me enough information to solve the problem!

Thanks for your help!

dave

Reply
Posts: 1
(@feassetep)
New Member
Joined: 13 years ago

Is anyone able to download the attached pdfs? All I get is a blank page when i click on the link.

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