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!

*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

SOL 701 - Problematic Behaviour of Ruptured Elements

SOL 701 - Problematic Behaviour of Ruptured Elements

SOL 701 - Problematic Behaviour of Ruptured Elements

I tried many to times to run an Explicit analysis, but I think Femap doesn 't behave as it should, or better, as other Explicit solvers do. Like LS-Dyna or Abaqus.
I tried to do something like this http://www.dynaexamples.com/intro-by-j.-reid/symtu... (select the animated result to see it better).

The LS-Dyna material of the tube is the well-known MAT_024 Piecewise Linear Plasticity. I made a stress-strain curve according to the example, also considering the "rupture" element flag in SOL 701 and the corresponding fail strain.

The problem is that when the elements fail, there are HUGE strains and displacements. The elements should not appear anymore, as with all Explicit solvers. I cannot understand why Femap present fail elements like this. It 's very annoying.

You can also see it on other models...

Can anyone give me a help on this problem?


RE: SOL 701 - Problematic Behaviour of Ruptured Elements

Also, in this video https://www.youtube.com/watch?v=hhqigu_PHCk, the same happens, but the user did the "trick" with the black backround and the black elements color and the problem is not well appearing.
Also, in the 3rd video here https://iberisa.wordpress.com/2011/12/05/analisis-..., you can see the strange white elements beside the bullet. By the way, the 4th video where it seems right, it seems that something 's going wrong with the Femap interface...that "TIME" up-left, definitely is not a femap feature. Maybe it 's not with NxNastran...

RE: SOL 701 - Problematic Behaviour of Ruptured Elements

Hi jacksonfem,

I'm not an expert but the wired element shape from secend picture in your post happened to me before. Usually the reason was too coarse mesh. With smaller elements it was fixed. Have you tried this already?

RE: SOL 701 - Problematic Behaviour of Ruptured Elements

I have tried also with smaller elements to other models, and I always had the same problem.
I have analyzed models with bigger elements on other explicit solvers, such as Ls-Dyna and Pam-Crash and never had such problems.
Only with NxNastran I have this annoying problems...

RE: SOL 701 - Problematic Behaviour of Ruptured Elements

The problem is that Femap does not have the opportunity for not showing the failed elements.
Below you can see the above file with the ball and plate, reading from another post-processor, not Femap.
In the first picture you can see the failed elements as it came from Femap, with grey color.
In the next picture the failed elements are not shown and the model is pretty nice!!

RE: SOL 701 - Problematic Behaviour of Ruptured Elements

I think you should take a look at View Options - Criteria Levels and "Elements that pass" vs "Elements that fail". Femap does have the functionality for not showing failed elements. I have used it but it was a while back so I don't remember directly how I did it.

Good Luck


RE: SOL 701 - Problematic Behaviour of Ruptured Elements

Criteria levels for elements that Pass or Fail has nothing to do with the visibility of the failed elements in contour style view results. Are for criteria style view results. But even if I turn the results presentation to criteria view, these parameters does not affect the view of failed elements.

If you search the web for Implicit/Explicit analysis with sols 601/701 with Femap, including ruptured elements, you can see that always the background, elements and element edges are black or white. With this way the results are presented better than with the default view colors.
I think that it 's something very simple that Femap must have.

RE: SOL 701 - Problematic Behaviour of Ruptured Elements


I only made it with criteria style. I set up right the criteria levels for pass and fail and it works fine. The failed elements are not showed. But in contour style the problem remains....

RE: SOL 701 - Problematic Behaviour of Ruptured Elements

Hi again
Well it has nothing to do with Criteria Levels, like you say, but instead it is Criteria Limits that should be used. I kney it was something with the criteria settings.

So Femap can do it, in Criteria Style mode.


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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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