stress-strain curve on Abaqus

[felipestumpf]

Hi everybody

I wrote a thread few days ago about how could I plot XY data on Abaqus without having as X-axis the time.
This problem I have already gone through.

My problem now is how to plot a stress-strain curve equivalent to that one I used to predict my hyperelatic material constants.

I was plottin for example, for a sheet under uniaxial tension in y direction, the stress S22 versus the strain LE22 but the experimental curve and the numerical one tend to be really different from each other. What am I doing wrong?
Please can somebody helpe me? It´s kind of urgent.

Thanks for the attention!!!

Felipe Stumpf

[Jorgen]

What material are you studying?
What material model are you using?
How did you calibrate the material model?

-Jorgen

[felipestumpf]

Dr.

I figured out what was I doing wrong...
First, I had to change my output options so abaqus could give me the strains NE instead Logarithmic strains LE. Then I had to print all reaction forces at my constraint line, sum them all and divide by the undeformed area of the sample (so I get Engineerign stress).
Now, my experimental and numercial data fits perfectly!!
I kind of lost a few hours until figure this out, but for all those who were having the same doubts that I had, please contact me and I´ll be glad to help.

Thank you all

[hamburg]

Dear Felipe (or anyone how can help),

could you please give me a hint how to get NE strains? I ask Abaqus to calculate ALL kind of strains, but I get a warning message:

***WARNING: STRAIN OUTPUT REQUEST NE IS NOT VALID FOR SOME ELEMENTS IN THIS
ANALYSIS. THIS REQUEST IS SWITCHED TO THE STRAIN MEASURE, E.

The element type is C3D8R. What are the restrictions for NE strains in general?

Thanks a lot
HamB