×
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

NODAL FORCES - ENFO
2

NODAL FORCES - ENFO

NODAL FORCES - ENFO

(OP)
Hi,

For unknown reasons, I cant get reasonable values of nodal forces for a scoped entity along the base of a weld. Any advise on the use of ENFO APDL command?

Thank you.


RE: NODAL FORCES - ENFO

Hard to tell what could cause this. What kind of values do you expect? It's hard for us to give any real advice without knowing loading conditions, boundary conditions and coordinate systems used. A plot of nodal forces along a line without further information is not sufficient information.

RE: NODAL FORCES - ENFO

(OP)
@petb, for some unknown reason, the solver gave correct values with a glued contact defined at the intersection, but not with shared topology (one complete surface). I suppose it had something to do with the native step file export?

RE: NODAL FORCES - ENFO

@Doodler3D Do you have activated Nodal Forces in Output Controls? Did you check your coordinate system in the user defined results? Are the dimensions and mechanical properties also correct?

Best regards
JK

RE: NODAL FORCES - ENFO

(OP)
Yes, I had activated the nodal forces in the output, as well as the co ordinate system was correct. I think I got it to work correctly.

RE: NODAL FORCES - ENFO

@Doodler3D so possible reason is bad connection via shared topology? I observe this behaviour from time to time but it usually ends by rigid body motion not wrong results.

What is your final solution? Do you create a model from scratch or you do a glued connection?

Best regards
JK

RE: NODAL FORCES - ENFO

(OP)
Yes, I did a glued connection. I'm not sure what went wrong. I was able to replicate MA Weaver's method correctly. Thank you.

RE: NODAL FORCES - ENFO

@Doodler3D Is it possible to share your STEP file to reproduce the same behaviour?

Best regards
JK

RE: NODAL FORCES - ENFO

Try selecting only the elements on the part with the hole with the forces. If all the elements are selected, the reactions sum to zero, as your plot shows. Thats why it works for bonded contact and not shared topography. And dont forget SPOINT at the centroid of the weld group so your moments are accurate.

Rick Fischer
Principal Engineer
Argonne National Laboratory

RE: NODAL FORCES - ENFO

(OP)
Thank you Rick/jkupka84, I think I figured it out.

RE: NODAL FORCES - ENFO

@Doodler3D
Hello, so your origin question was to have separate parts, no share topology and to have contact (weld) between these parts. I see the point thanks to @rickfischer51

RE: NODAL FORCES - ENFO

You can have shared topology, but you have to select the elements on the edge of one of the parts to be joined by the weld, and then select the nodes on that edge. Put a local CSYS at the origin of the weld group, and set the SPOINT as the global coordinates of the local CSYS. Set the RSYS to the local CSYS, then do FSUM,RSYS. The resulting reaction forces will be in the correct csys and the reaction moments will be around the centroid of the weld group.

Rick Fischer
Principal Engineer
Argonne National Laboratory

RE: NODAL FORCES - ENFO

(OP)
@jkupka84 the default is to use shared topology/continuous mesh, and avoid the use of MPCs and contact, especially large models.

Rick, now its clear, define a local co-ordinate system while extracting unaveraged nodal forces for sizing welds.

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