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


FEA elastic region not following experimental

FEA elastic region not following experimental

FEA elastic region not following experimental


I am trying to simulate uniaxial tensile test on 50mm gauge length stainless steel specimen on Abaqus. My problem is only in the elastic region it does not match experimental results, and the plastic region is 99% matching my experimental results. My model is explicit with Hex 8 node reduced integration solid element.

I have tried to manipulate young modulus ( stiffness E ) I have lowered it from 190 GPa to 160 GPa , but it did not change my FEA results which does not make any sense. What should I do ?

RE: FEA elastic region not following experimental

Does your analysis feature geometric nonlinearity (NLGEOM on) ? Did you try with full integration second order elements ? Did you check the results from Standard analysis ?

RE: FEA elastic region not following experimental

Maybe the experimental data is wrong. ?
You have not posted enough details to make any useful replies.
If changing the modulus does not change the load-strain curve you are doing something wrong.

RE: FEA elastic region not following experimental

"I have tried to manipulate young modulus ( stiffness E ) I have lowered it from 190 GPa to 160 GPa , but it did not change my FEA results"

What results ? Stress ?

RE: FEA elastic region not following experimental

NLGEOM is on , no I did not try full integration second order element , yes I have checked with implicit analyses it was very good in elastic region but at high strain before failure the analyses stops ( due to high non-linearity ). sorry I did not explain my self , when I say results I means pulling force vs elongation ( displacement ). From experimental test I have both ( stress vs strain ) and ( pulling force vs elongation ) graphs.

what I am trying to do is to make sure that my material data , boundary condition and my other inputs and method in general are correct to simulate spot weld under uniaxial tensile test with constant pulling velocity ( constant strain rate ).

At the moment both of my explicit simulation for 50mm length specimen sheet and single spot weld have problems in elastic region. I have even tried implicit analyses for spot weld but I got the same results as explicit in elastic region. I will post the results to be more clear , I will try full integration second order element now. I appreciate your help

RE: FEA elastic region not following experimental

I have tried quadratic hexahedral element ( C3D20R ) using implicit analyses , now my results are excellent for specimen tensile test as shown in the pic here , I think my problem was I have to increase the number of elements through the sheet thickness or use a better element like ( C3D20R )

as for spot weld the results did not change ( in the elastic region ) when I tried quadratic hexahedral element compared to explicit analyses using C3D8R element ( I did not post the results for C3D20R standard element ) . For the spot weld I am using 3 element through plate thickness as shown in the pic

The results shows that my Abaqus model seems to be too stiff compared to lab experiment but I dont know why
. What should I do ? my stiffness E is 185 GPa this time when I changed it to 120 GPa the results didn't change much.

RE: FEA elastic region not following experimental

Solved the problem ,I made a new experimental test.

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! Already a Member? Login


White Paper - The Criticality of the E/E Architecture
Modern vehicles are highly sophisticated systems incorporating electrical, electronic, software and mechanical components. Mechanical systems are giving way to advanced software and electronic devices, driving automakers to innovate and differentiate their vehicles via the electric and electronic (E/E) architecture. As the pace of change accelerates, automotive companies need to evolve their development processes to deliver and maximize the value of these architectures. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
Modern cars, trucks, and other vehicles feature an ever-increasing number of sophisticated electrical and electronic features, placing a larger burden on the wiring harness that enables these new features. As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - Modeling and Optimizing Wire Harness Costs for Variation Complexity
This paper will focus on the quantification of the complexity related costs in harness variations in order to model them, allowing automated algorithms to optimize for these costs. A number of real world examples will be provided as well. Since no two businesses are alike, it is the aim of this paper to provide the foundational knowledge and methodology so the reader can assess their own business to model how variation complexity costs affect their business. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close