Inventor General Discussion

Inventor General Discussion

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Member
robertpugh8785
Posts: 9
Registered: ‎11-29-2010
Message 1 of 3 (353 Views)

FEA - sliding/no separation on spherical surfaces

353 Views, 2 Replies
03-21-2012 03:52 PM

Hello.  I'm trying to set up a sliding/no separation contact within and assembly for FEA purposes.  I want to eliminate all moments (torque) between two pieces while still allowing one to impart force on another.  When evaluating constraints, I'm seeing moments are infact being passed through.  The guide mentions this contact for planer and cylindrical objects but makes no reference to spherical surfaces.

 

Is it possible to accomplish this type of a contact on spherical surfaces?

 

Thanks in advance

Product Support
Daren.Lawrence
Posts: 193
Registered: ‎11-04-2003
Message 2 of 3 (321 Views)

Re: FEA - sliding/no separation on spherical surfaces

03-26-2012 01:29 PM in reply to: robertpugh8785

You can use a sliding/no separation contact on two spherical objects, but help us to understand: It almost sounds like you want to see a collision between the two spherical objects while eliminating any torque between them and that would be more of something we could do in dynamic simulation – you can lock joints’ ability to move in a direction. Could you supply the files and an image of where you’re seeing the unwanted moments? Thank you.



Daren Lawrence
Product Support Specialist
MFG Support - Inventor
Autodesk, Inc.


http://beinginventive.typepad.com/being-inventive/
Member
robertpugh8785
Posts: 9
Registered: ‎11-29-2010
Message 3 of 3 (317 Views)

Re: FEA - sliding/no separation on spherical surfaces

03-26-2012 01:42 PM in reply to: Daren.Lawrence

Hello.  Thanks for the response.  I think I may have figured out the problem here...

 

To help contrain my assembly for static FEA, I add a couple of extra parts in the assembly that I could place sliding/no separation contacts to (spherically shaped feature on each part).  These extra parts were attached to the assembly in such a way to to simulate the reaction vectors, while greatly simplifing the model.

 

I set the modulus of elasticity of these two extra parts to be 100 times stiffer than steel so they wouldn't deform during analysis.  This seems to be the cause of the problem as I later set one of the spherical parts to be aluminum while the other stayed with the modulus 100 times that of steel.  This seems to allow the sliding/no separation to behave as expected.

 

Thanks again

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