NX: Surface-to-surface contact unrealistic results

[Xevuhtess7]

Hello, first post here after many times finding solutions to my problems here.

My model is simple: a pin (flanged on both ends) inside a sleeve. The outer surface of the sleeve is fixed, and the pin's flanges are surface-to-surface glued to the top and bottom of the sleeve. I have a surface-to-surface contact between the pin and inside of the sleeve. Load is a force applied to the pin radially.

In the results (see picture) the pin shrinks radially and both pin and sleeve have very unusual deformation/stress at the flanges. Removing the surface-to-surface contact results in realistic deformation/stress (of course with the pin being pushed through the sleeve due to lack of contact condition)

What could cause things to behave so radially when adding the surface contact condition?

I have had success using surface-to-surface contact on other models, but those involved non-cylindrical geometries. Does the contact condition surrounding the pin on all sides cause a problem?

 

[BlasMolero]

Hello!,
You have a problem of INITIAL PENETRATION between contacting mesh, this is very typical, take a look to my post in the following address:

http://iberisa.wordpress.com/2012/0...cto-lineal-con-inipene-en-femap-y-nx-nastran/

The INIPENE parameter control the undesired penetration, setting INIPENE=3 solves the problem. But the best solution is to act at the mesh level: make both source & target mesh to be exactly coincident, this will avoid physical interferences.

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48011 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

http://iberisa.wordpress.com/

 

[Xevuhtess7]

Blas,

That makes complete sense. Thanks for the tip! My model runs as expected now.