Simulation Mechanical Forums (Read-Only)
Welcome to Autodesk’s Simulation Mechanical Forums. Share your knowledge, ask questions, and explore popular Simulation Mechanical topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Real life deformation

4 REPLIES 4
Reply
Message 1 of 5
drpalo
548 Views, 4 Replies

Real life deformation

Good afternoon all,

 

MES with nonlinear models. We're trying to recreate a field failure but we're not seeing the buckling that occurred. Even with almost 10x the load. Model, gravity, material info, loads, constraints, displacement settings are correct. Element properties are set to large displacement. Is there a plasticity setting or something else I need to look at?

 

Thanks.

Autodesk Product Design Suite 2016
Dell Precision T5610
HP Z800 Workstation
4 REPLIES 4
Message 2 of 5
drpalo
in reply to: drpalo

It looks like part of the reason is because the strain hardening modulus in the Algor materials are set to 0. Why is this? How do I change this read only library? Anything else I'm missing?

 

Thanks.

Autodesk Product Design Suite 2016
Dell Precision T5610
HP Z800 Workstation
Message 3 of 5
John_Holtz
in reply to: drpalo

Hi Dr. Palo,

To answer your questions,

  1. The material properties are incomplete in some cases because they are all from public sources. If the source did not have a material property, then we could not provide it. (Sure, some things could have been combined from more than one source, but I would prefer that a user make that decision, not us. Some properties depend on the treatment for the material and so on, so different sources may be testing "different" materials.)
  2. The libraries provided by Autodesk are locked and cannot be changed. However, the libraries can be copied, which then become a "customer library". The values in any customer library can be changed, so this is what I suggest for your case.
  3. Buckling is highly dependent on the mesh "accuracy" and "quality". Also, real life can include manufacturing imperfections which may be important compared to an "ideal" model. I don't know if this is related to you "bridge model", but that model looked as if it were made from rolled sections which have tolerances for straightness, parallel-ness of the flanges, manufacturing tolerances, and so on.
  4. Does the structure include any vibration or wind loads that might affect the eccentricity of the loads?
  5. Of course, a strain hardening modulus of 0 indicates that the material is perfectly plastic. So I would think that this would buckle more easily than a beam with the real strain modulus. But this implies that the buckling was due to plasticity instead of elastic instability.



John Holtz, P.E.

Global Product Support
Autodesk, Inc.


If not provided already, be sure to indicate the version of Inventor Nastran you are using!

"The knowledge you seek is at knowledge.autodesk.com" - Confucius 😉
Message 4 of 5
drpalo
in reply to: drpalo

Thanks for the response John,

 

Yes, this has to do with the "bridge like" structure I've been working on. A lot of the lower beams that are in compression were rusting away & eventually failed. I thinned these areas out in the model & overloaded it to show some buckling. We're just surprised it hasn't happened yet.

Autodesk Product Design Suite 2016
Dell Precision T5610
HP Z800 Workstation
Message 5 of 5
drpalo
in reply to: drpalo

Is von Mises with Isotropic Hardening the correct material model for showing buckling?

 

Thanks.

Autodesk Product Design Suite 2016
Dell Precision T5610
HP Z800 Workstation

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Autodesk Design & Make Report