×
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

No Convergence on Sol106 MSC.Nastran

No Convergence on Sol106 MSC.Nastran

No Convergence on Sol106 MSC.Nastran

(OP)
Hallo,

My problem is, that my Modell is not converging.

I generated a 3D Modell of a double lap shear rivet connection. Rivet an Sheet are modelled with Hex8 Elements. Between the Rivet and the Sheet is a small gap. The connecting nodes there are connected with CGap Elements. (Because MSC.Nastran doesn't provide 3D Contacts)

When I run this nonlinear, I always get convergence problems. Because of excessive pivot ratios at the Gap Element nodes on the Rivet. The rivet is free in sheet directions, but constraint, rotational constraint normal to this direction.

Some of the Parameters, I used are:

NLPARM,1,10,,AUTO,5,25,UPW,NO
      .01,.01,.01
PGAP,3,.01,,5.+7,.005,5.+6         

Thanks
Tobias       

RE: No Convergence on Sol106 MSC.Nastran

you can manipulate the nlparam options for convergence, but in general the more complicated the model, the higher chances you have of not making it work.

have you tried a finer mesh?

Jake.

RE: No Convergence on Sol106 MSC.Nastran

(OP)
Hey JacobL,

no, I didnt try a finer mesh. but the mesh is very fine already. And I played alot with the nlparam values.
What I found out recently is, that a 3D contact cant be done with MSC.Nastran. (it is hard to model a 3D contact with 1D elements)
So I changed to Ansys.

Thx 4 the post

RE: No Convergence on Sol106 MSC.Nastran

actually, for nonlinear solutions, msc marc is the answer..

nastran is not really good at non linear question.

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


Resources

Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now
eBook - Managing the Context of Product Complexity Using the Digital Twin
Keeping track of changes to complex products is difficult—think Aerospace & Defense equipment, new generations of commercial aircraft, and software-based automobiles. A new way to managing the digital context of the physical product is required and the answer is the Digital Twin. This ebook explores the opportunity available for Operations and Maintenance for the Digital Twin. Download Now
White Paper - Trends in Industrial Filtration
Substantial progress has been made in filtration technologies in recent years. New filter media materials, designs and processes have led to filters that are more efficient, reliable, compact and longer lasting. This white paper will discuss the various trends that are impacting operational responsibilities of MROs today and the resources that are available for staying up-to-date on the latest filtration solutions. 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