Contact US

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

Spring vs Gap Elements in Nastran

Spring vs Gap Elements in Nastran

Spring vs Gap Elements in Nastran

I am trying to get a better understanding on Gap vs Spring elements in Nastran and their usage. Would appreciate some help with possible physical case for each item.

Per my current understanding, gap elements are more suited for cases where compression (contact) is expected. For example: fastener bearing and heel to toe interaction.

Springs can take both compression & tension and thus if one wants to model rope, a spring representation would be more effective.

Am I correct?

Edit: I trying to find tutorials on Patran's Linear Gap Tool. I've found MSC documents on Non-linear gap elements but nothing yet on Linear Gap Tool, expect a MSC powerpoint presentation dated Oct 2001. On Patran 2014, I am not able to find Linear Gap Tool PCL function. Would appreciate if someone could point me to a decent tutorial as well as finding Gap tool on Patran 2014.


RE: Spring vs Gap Elements in Nastran

Gap elements are mostly used for sol106 where there will be some contact between parts. So, try to review examples of gap usage for sol106 eapecially.

Per linear gap element utility in patran, patran made a change in sol101 as I understand it. You can use contact card for sol101 in patran2014 and it will be less work to model and for accuracy compared to the patran 2005 linear gap elements utility. Hope this is clear enough. Just check msc website for case studies or google for patran 2014 version. You should be able to find more about the contact card for sol101 in patran2014.

Aerospace Engineer, M.Sc. / Aircraft Stress Engineer

RE: Spring vs Gap Elements in Nastran


>Springs can take both compression & tension and thus if one wants to model rope, a spring representation would be more effective.

I think you need to be careful before this conclusion is made. A rope works as a tension not in compression. So a spring element will not be ideal for this application.

The use of a GAP element (linear or non-linear) puts additional labor on the modeler to maintain an identical mesh at the region where the gaps are going to be used.

As mentioned by the previous poster, body contact is a good way to address such problems as they are a lot easier to set-up in terms of modeling time.

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