Inventor General Discussion

Inventor General Discussion

Active Member
7 Posts
0 Kudos
Registered: ‎02-01-2012
Post 1 of 5

Contacts, Stress analysis

498 Views, 4 Replies
10-15-2012 12:31 AM



I am trying to calculate flex on a metal ring I have designed and are a bit confused with the contacts that I am getting when using automatic contacts.

Please see the pictures attached for reference.


When I use automatic contacts I get all bonded contacts, but I get the impression that bonded contacts are welded and that is not the case with my design it is bonded using bolts.


Which contacts would you use for this part? Or should I simplify it? Can I run it in the stress simulator?




Active Member
7 Posts
0 Kudos
Registered: ‎02-01-2012
Post 2 of 5

Re: Contacts, Stress analysis

10-16-2012 01:52 AM in reply to: JohanQleeno


*Expert Elite*
647 Posts
200 Kudos
Registered: ‎11-05-2003
Post 3 of 5

Re: Contacts, Stress analysis

10-16-2012 02:55 AM in reply to: JohanQleeno

I was thinking of this yesterday when I saw the post and am also interested in replies as I've only started dabbling with stress analysis too.


My thoughts (as a discussion point, not a definitive "this is the answer"):

bonded contacts between screw threads (screw OD face and hole ID face)

sliding contacts between the face of each "block" and the mating face of the curved piece


and now, this is where I'm not sure...

sliding contact between CSK screw head and the CSK hole? (so the screws hold the plate to the blocks, as they would in real life).


Is that it, does it need more?


Also interested about the assembly method - without knowing what it's for I admit I'm in the dark, but on the face of it I would have thought you'd offset the top ring 45 degrees to the bottom ring, to prevent having both the top and bottom ring having a joint on the same block - if that makes any sense.  Is there a benefit in not offsetting the top to bottom ring?

Please mark this response as "Accept as Solution" if it answers your question...
but please understand that the solution may not be the answer you're wanting to hear...

If you have found any post to be helpful, even if it's not a direct solution, then please provide that author kudos - spread that love :smileyvery-happy:

Lithium - helping nntp users with mania, depression and headaches
Active Contributor
44 Posts
6 Kudos
Registered: ‎08-07-2002
Post 4 of 5

Re: Contacts, Stress analysis

10-16-2012 07:29 AM in reply to: JohanQleeno
I would simplify the model by using symmetry - that way you can go to a finer mesh without consuming huge processing times: - split horizontally through the middle - analyze 1/2 of one ring section The model will be 1/16 as complex. - apply a frictionless constraint to each of the faces where a part has been cut in half (but not the free end of the ring section I would try the following contacts - between the rings and the spacer blocks - Separation - between the screw heads and the countersunk surfaces - Separation - between the screw body and the tapped holes - Sliding - No Separation Now model the pre-loading of the threads. If memory serves, the first 3 threads do all the work so: - split the hole at that depth and apply an upward load (assuming upward is toward the ring section) equal to the pre-load of the screw - split the screw body at the point where it enters the threaded hole and again at the depth that you'd split the hole. Apply the pre-load to the screw drawing it downward. Simulate. You might repeat this after changing the contact between the screw head and the countersink to Separation-No Sliding because under load there is friction. I would expect to have to refine the simulation further but this would be a start. Richard
IV 2013 Product Design Suite 64 Bit
Win 7 64 bit
281 Posts
24 Kudos
Registered: ‎05-06-2011
Post 5 of 5

Re: Contacts, Stress analysis

10-16-2012 11:54 PM in reply to: rhinterhoeller


form my experience I would say that chousing how to model constrain in some part schould depand on what results you need. I mean what loads you apply and what areas of construction (model) are most intersting to you.


Sometimes it is not worth an effort to play with rather complicated contact definition because it has rather small influence on are that one is most interested.


If you post files and describe loads you apply and kind of results you are most intersted in it would be helpfull in looking ito case.




Post to the Community

Have questions about Autodesk products? Ask the community.

New Post
Are you interested in helping shape the future of the Autodesk Community? To participate in this brief usability study, please click here. Your time and input is greatly appreciated!