Discussion Groups

Simulation Mechanical and Multiphysics

Reply
Distinguished Contributor
feldwill
Posts: 114
Registered: ‎10-31-2006

Best way to constrain

341 Views, 2 Replies
02-19-2013 10:26 AM

This is an easy one (I think).  Please see picture attached.

 

What is the right way to constrain my hub so no sufraces are really fixed.  But aside for deflections hub can not go anywhere?

 

Thank You

Best Regards

William

Please use plain text.
*Expert Elite*
AstroJohnPE
Posts: 547
Registered: ‎08-30-2012

Re: Best way to constrain

02-19-2013 10:58 AM in reply to: feldwill

Hi William,

 

  1. Select 3 random points throughout the hub, but the points cannot be in a straight line.
  2. Add "Setup > Constraints > 3D Springs" to the three points. Fix the X, Y, and Z directions. Make them translation springs with a small stiffness.

That's it! Three "fixed" points are sufficient to prevent motion in all directions, and the low stiffness will let the part deflect without transmitting too much force through the springs to the ground.

 

P.S. I see that the "Contact (Default: )" is set to Free. This indicates that no parts will contact any other parts. Is this really what you want?

 

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16.9 years experience with Simulation Mechanical
Please use plain text.
Distinguished Contributor
feldwill
Posts: 114
Registered: ‎10-31-2006

Re: Best way to constrain

02-19-2013 11:28 AM in reply to: AstroJohnPE

What would you suggest for  contact, The function is obvious, hub clamps to shaft.  Right now I have it drawn with .003" gap ID to OD, which is the worst case condition.  I'm checking clamping deflection after bolting.

 

I put 3 springs and changed Contact to "Surface", my deflection is .0001" which is tiny and I expect more then .003".

 

See pics attached.

Regards

William

 

 

Please use plain text.