×
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

problem for plotting stress strain curve

problem for plotting stress strain curve

problem for plotting stress strain curve

(OP)
Dear all,
I am new with Abaqus. I am trying to plot stress-strain curve of a metal with Abaqus.
I gave Young's modulus, Poisson ratio and yield stress corresponding plastic strain.
After analysis the result didn't seem what i provided. Such as i provided maximum yield stress of 65 corresponding plastic strain of 0.155 but it showed maximum yield stress of 75 corresponding plastic strain 0.14
Any one can suggest me what is the problem?
My .cae file and .odb file link is


https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B-f1ExuLyrxNNjI2MTliNjMtMzJkOS00ZjNiLWFjNWEtN2JlOTA1OTZkMTFi&hl=en_US  

Thanks.
Abu Hena Muntakim

RE: problem for plotting stress strain curve

You're probably looking at nodal stresses which have been extrapolated from the element integration points, hence a slight error can occur. The element stresses should follow the input stress-strain curve. Use a finer mesh to reduce this error.

RE: problem for plotting stress strain curve

(OP)
Dear corus,

i tried with fine mesh but it didn't  match with input stress-strain curve.
i also tried to make avg. value of nodal stress and strain but no change.

how can i see the element stress?

when i turn on nlgeon then in contour there are stress strain variation but if i turn it off then no change in stress strain in the part.why this happen? Can you please help me with the reason?

i have a test result curve of stress and strain. Is there any special thing to give input in yield stress and plastic strain.

Thanks.

RE: problem for plotting stress strain curve

You have a number of basic problems here..I'd strongly advise you to read the getting started Abaqus manual and do some of the tutorials.

Your boundary conditions do not constrain your part sufficiently for a uni-axial tensile test. NLGEOM should be on as you are dealing with finite deformations.You are also assuming plain strain,which I imagine is one of the main sources of the discrepancies in your results.

When entering plasticity data it should be in the form of true stresses and plastic strains. Technically these stresses should never decrease, to mimic failure you should introduce a damage model or an imperfection.

RE: problem for plotting stress strain curve

(OP)
Thank you very much MechIrl.
i have done this job with 3D model.
getting started with Abaqus helps me to give right input format of material.  

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