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

Problems with Patran

Problems with Patran

Problems with Patran

Hello guys, I'm a spanish student and I have a FEA subject on my automotive engineering degree. We have to make a quick PATRAN final project. Not very elaborated, but it has to be ok and show the results after calculating. I designed a Moto 3 chassis in Catia V5R21 (not very good but I did it in 10 minutes) only with lines.

My idea was to import my lines geometry from catia in .stp format and once in Patran give it 1D Beam properties. I did it, put the load cases and fix points, meshed etc but after calculating and trying to import the HDF5 data to see the results I always get the same error message. Someone knows which mistakes am I making?

I attach too the .db file in case someone would like to inspect it in detail.

Thank you all very much in advance.

RE: Problems with Patran

The HDF5 is not being attached because it does not contain any results information. This is because your model will not run in linear statics in the current configuration. The elements at the locations indicated below are not connected. The head-stock of the frame is not connected at all to the frame (the 2 left most arrows), and the two triangulations are only connected at one end.

You will see which parts of the structure are unconnected if you run a normal modes analysis and request at least 10 modes.


RE: Problems with Patran

Thank you very much for your help! Do you know how can I do to connect those points? I tried in Catia but it is impossible...

RE: Problems with Patran

You have 2 possibilities:
1. Modify the geometry in Patran.
The geometry was imported as curves. Curves connect to points. Make sure the curves for the headstock connect to the same points that the frame connects to otherwise when you mesh, the mesh will be unconnected. Same remark for the triangulation curves. Once connected, then remesh.

2. Modify the mesh
Use Finite Elements, Modify, Node, Move to move the 2 nodes of the headstock closest to the frame junction so that the node of the headstock is coincident with the node of the frame. Do the same thing for the triangulations. Once all is in the right place, use the Finite Elements, Equivalence, All capability to "merge" or "equivalence" nodes that exist at the same geometric location. This will connect the mesh and delete the now unused duplicate nodes.

As a last remark, I notice you applied the fixed node boundary condition to the geometry (points). Be careful here. If the curve/point is not "associated" to the nodes, the boundary condition will not be applied. It seems attractive to use geometry to define the boundary conditions, but I _always_ use the FE (nodes/elements) to define BC's.


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