×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

hyperelasticity -large deformations problem

hyperelasticity -large deformations problem

hyperelasticity -large deformations problem

(OP)
I have the following problem:

I have a silicone material and I have the uni-axial tension test data results and his poisson ratio.
I filled these data in,in a hyperelastic material with Marlow.

I simulate a tension test on a dogbone to see wether my material act in Abaqus how it should react. The dimensions of the total dogbone are 150mm x 20mm x 1mm.I use Z-symmetry so my model has a thickness of 0,5mm.

My mesh: I use C3D8H elements

My step: I use NLGeom=on and my beginning increment=0.005

When I have strains up to 0,05, the stresses are OK but with higer strains , the stress is too high. The curve of my material model is a convex curve and the strain-stress curve I become with Abaqus is a concave curve.

I already tried the following things:
- I evaluated my hyperelastic material, it is stable for all strains and follows the test points
-I used other potential strain energy models like polynomial, N=2.
- I refined my mesh and have convergence for my results. So mesh is fine enough, I think.
- I used C3D20H elements en C3D8HR elements, the same results.
-I have no warnings that my elements are too heavily distorted.

Can you help me? I don't know what I can change to solve the problem.

RE: hyperelasticity -large deformations problem

Hi,

I'm not sure how helpful this may be but are you inputting your experimental data and post-processing your numerical data correctly?

For hyperelastic materials ABAQUS requires nominal stress and nominal strain but outputs true stress and true strain. Maybe this is causing a discrepency?

Dave

RE: hyperelasticity -large deformations problem

(OP)
Thanks Dave,

I forgot that Abaqus gave the true stress and strain.
Now it looks a little bit better :)

Lies

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources