×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

How much gap between parts in assembly?

How much gap between parts in assembly?

How much gap between parts in assembly?

(OP)
Hello all,

I am working on the assembly with different parts. I know this is the contact nonlinear problem. What is the amount of the gap need to be in order to model the real case? I know the gap will strongly affect the contact pressure between parts. The problem is not press-fit, should I use the tolerance in the design to put into FEA? Thanks for help.

RE: How much gap between parts in assembly?

If you leave a gap then the two surfaces may never contact, so what have you proved then? It's best not to assume tolerances will leave a gap but assume the worst and have the surfaces in contact (if that is the worst case). There's also an option to move the nodes so that they touch and don't overlap. It's best to use that.

corus

RE: How much gap between parts in assembly?

(OP)
corus,

Thanks for your quick response. I am quite curious if I make two parts contact with each other, do the auto-meshing mesh the whole parts together, like one parts, instead of two parts. Just like two parts welded together. Of course, I know, I need to define the "slave" and "master" contact surface, tangential behavior, frictionless, sliding formulation options!

The option that you mentioned is "slave node adjustment"?

RE: How much gap between parts in assembly?

No. Abaqus meshes parts separately. If you want a single part and can't be bothered creating it in the part module, then you can tie the nodes together.
The slave node adjustment is the option to move nodes to be touching, initially. Be careful with this though, as if you have a gap then the model will be distorted as the nodes from the slave surface are moved to the master surface. Too big a gap and you can get odd results or even the job failing due to element distortion.

corus

RE: How much gap between parts in assembly?

(OP)
Thanks corus, it seems you are the chairman for this particular group. In short, you means no gap between parts is the worst case and common practise for the contact problem in the large assembly.

RE: How much gap between parts in assembly?

"To be or not to be, in contact, that is the question" as Shakespeare once said (later edited).
If you had a beam resting on three supports , ie. one support was redundant, then you cannot guarantee that all three supports are in contact. For a case like that I might consider the worst case of only having two supports for a design case scenario.

corus

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

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