Inventor Nastran Forum
Welcome to Autodesk’sInventor Nastran Forums. Share your knowledge, ask questions, and explore popular Inventor Nastran topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Interference Fit (No Sliding) Results Looking a bit Dicey - Non Linear Static Study

1 REPLY 1
Reply
Message 1 of 2
Ruwan.B
84 Views, 1 Reply

Interference Fit (No Sliding) Results Looking a bit Dicey - Non Linear Static Study

Hi Guys

 

I'm studying the effects of an interference fit (no sliding) in a non-linear static environment. Initially, the results seemed fine—displacement close to the specified interference, and compressive stress appeared acceptable.

 

However, as I dive deeper into the results, they seem inconsistent and inconclusive. My main concern is the significant variation in contact pressure and force between iterations, which makes me uncertain about the reliability of the results.


Now the parameters I have are as follows:
SLINEPOSTOL = 1E-3

ENHCCONTACTRSLT = ON

NCONTACTGEOMITER = MODIFY (1)

 

The interference fit is defined with a manual contact (shaft as master), a node ratio of 1.5, and a maximum activation distance of 1.2 times the master’s mesh density.

 

I'm unsure how sensitive the interference fit analysis is to mesh density, but I wouldn't expect such significant variation.

Has anyone encountered this issue, or is there a parameter I might be overlooking?

 

Any help in this matter will be greatly appreciated :slightly_smiling_face:


Inventor Nastran 2024

 

Thank you all

Labels (4)
1 REPLY 1
Message 2 of 2
John_Holtz
in reply to: Ruwan.B

Hi @Ruwan.B 

 

The first subcase of an analysis with an interference fit is changing the contact stiffness with each iteration to get the proper interference. The variation in your plots is typical.

 

In other words, the "Load path" and "Load increment" are not changing any load. (Other than the shrink fit, there is no load in the first subcase. You should not expect to see the result increase uniformly.) The only result that it valid in the first subcase is the last step and whether the solution has converged or not. What I see in your plot is the result is converging nicely between steps 5 and 8.

John_Holtz_0-1735828829898.png

 

Subcase 2 is missing the Y symmetry constraint.

 

John



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 :winking_face:

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

Post to forums  

Autodesk Design & Make Report