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

FEA Warnings: No Contacts Attached

12 REPLIES 12
Reply
Message 1 of 13
LT.Rusty
1634 Views, 12 Replies

FEA Warnings: No Contacts Attached

So I'm working on a traffic rated utility vault cover right now, and I'm doing some FEA runs on my cover design.  My initial run showed me that I needed a little bit of extra strength in a couple places.  My welds on this design are stitched.  Initially I used 3" welds on 5" centers.  To add a little more strength, I increased the welds to 4" welds on 6" centers... and that's where the fun started.

 

When I went back into the stress analysis environment I (obviously) needed to update the contacts.  Once I did this, I clicked simulate ... and got a warning about bodies with no contacts attached.  So far, the only way that I've found to make this go away is to delete the whole simulation and then create a brand new one.  Anyone have any better ideas or workarounds?  Anyone know of a way to delete all the automatic and manual contacts and start over without deleting the whole simulation?

 

Unfortunately there is no way to predict which assembly this will happen with - just now I spent a few minutes to create an example that I could post here, and of course no matter what I couldn't get that to spit up the same error messages.

 

I can share the data set that's currently giving me problems with Autodesk, but unfortunately I can't just post it here since it's a new product under development.

 

 

Rusty

EESignature

12 REPLIES 12
Message 2 of 13
henderh
in reply to: LT.Rusty

Hi L.T. Rusty,

 

  If you can email the dataset to me, we can take a look at why the message is being thrown.  hughDOThendersonATautodeskDOTcom.

 

  That said, there isn't a way to delete the Auto-contacts that I know of.  One workaround could be to create a new simulation, then Copy the loads, constraints, etc. and paste them in the new simulation.  You can RMB=> paste on the "new simulation" top node in the browser, not having to paste directly on the Loads browser node (for example).

 

Best regards, -Hugh



Hugh Henderson
QA Engineer (Fusion Simulation)
Message 3 of 13
LT.Rusty
in reply to: henderh

As soon as I can get it to throw up that error message again I'll email you the files.  I suspect I'll get something today.  It just feels like one of those days.

Rusty

EESignature

Message 4 of 13
LT.Rusty
in reply to: henderh

Okay, check your email Hugh.  I really appreciate your looking into this for me!

Rusty

EESignature

Message 5 of 13
henderh
in reply to: LT.Rusty

Hi L.T.Rusty,

 

  I've received your email and dataset.  We're looking into it and will let you know our findings as soon as possible.

 

  Thank you for bringing this to our attention, and we apologize for the inconvenience this is causing.

 

Best regards, -Hugh



Hugh Henderson
QA Engineer (Fusion Simulation)
Message 6 of 13
LT.Rusty
in reply to: henderh

Thank you sir! 

 

Of course with the way my luck is running this week, even with the data set the issue won't reproduce on your computer.  🙂

Rusty

EESignature

Message 7 of 13
henderh
in reply to: LT.Rusty

You're more than welcome Sir! Smiley Happy

 

  The issue is logged into our internal tracking database as 1489876, on it's way to Development for further investigation.

 

   Thanks again for bringing this to our attention.  Please let us know if you have any additional questions, comments or suggestions.

 

Best regards, -Hugh



Hugh Henderson
QA Engineer (Fusion Simulation)
Message 8 of 13
sebastian.sosa
in reply to: henderh

Any news on this issue?

I'm currently working on the 2014 version and I'm also getting that warning on several ocations. I don't know if the original post was about an assembly or a multibody part. I'm working with a multibody part. I've tried to create a manual contact between the part the message warns me about and the adjacent parts but it says it already exists (even tho the browser doesn't show them). When I run the simulation it behaves like in fact all the bonded contacts between the parts exists and after that the contacts appear in the browser. Is this some "bug" or something that I should just ignore or am I missing something else?

 

Thank you for your response

Message 9 of 13
LT.Rusty
in reply to: sebastian.sosa


@sebastian.sosa wrote:

Any news on this issue?

I'm currently working on the 2014 version and I'm also getting that warning on several ocations. I don't know if the original post was about an assembly or a multibody part. I'm working with a multibody part. I've tried to create a manual contact between the part the message warns me about and the adjacent parts but it says it already exists (even tho the browser doesn't show them). When I run the simulation it behaves like in fact all the bonded contacts between the parts exists and after that the contacts appear in the browser. Is this some "bug" or something that I should just ignore or am I missing something else?

 

Thank you for your response


 

 

The problem that I was having was with an assembly with welds, and how Inventor was auditing the contacts between the welds and the parts.  Short version, if I did something that reduced the number of weld beads (for instance going from a 1-3 stagger to a 3-5 stagger over the same seam length), then went back to the simulation, Inventor would barf on it because it was expecting to find X number of bodies in the weld object, but there were suddenly less bodies than it was expecting, and it got confused about contacts at that point.

 

The problem it sounds like you're having ... I'd recommend spinning your multibody solid off into an assembly instead, and then re-run your simulation that way.

Rusty

EESignature

Message 10 of 13
sebastian.sosa
in reply to: LT.Rusty

Hello, and thank you for your response.

I have, in fact, changed some parameters and minor geometry in between simulation runs (I forgot to tell that in my last post) , but I haven't changed the number of bodies of the part. It seems to be an issue with some "random" changes in the part/assembly because it's not a warning that I get every time that I make a change but I do get it more that I would want (getting warnings when performing a simulation is not an ideal situation). But since the warning dissapears when I run a second simulation after the one with the warning (being that the contacts appear on the browser after the one with the warning) I was hoping it was nothing to be too concerned about because regenerate all the constraints and loads every time I get this error would be very time consuming sometimes and on that note, I wouldn't know if the warning would appear again if I make a change on the original part ((assuming I use the "make components" option to create the assembly and keep the link to modify just the original multibody part because that's where all the rules between parts are) or if it would have the same behavior since your issue was with an assembly.


Thanks again for your response,

 

Best Regards

Message 11 of 13

i've had similar problems that occurred on re-running a simulation after turning visibility of some components off. the solver would no longer be able to recompute contacts for the components that were hidden when i re-run the simulation, and from then on there was no way to reset or restore contacts

 

any help would be much appreciated thanks

Message 12 of 13

HI,

I also had numerous problems with FEM.

 

I had reported support case no 09051207.

 

Perhaps Autodesk team could look in to this again as it was not solved.

 

 

From my experience I suppose there are problems related to the fact inventor is not capable of updating FEA data 100% correct. I had situations in the past when data was totally mixed up and obviously taken from old version instead of new. In consequence there was no other way but to delete whole simulation and recreate it.

 

Cris.

Message 13 of 13


@jared.crutchfield wrote:

......

 

any help would be much appreciated thanks


You "hijacked" an old thread from an experienced user - resulting in less likely chance of getting help for your specific problem as (and more likely to get speculative responses of no real value) most would assume the original problem was getting addressed.

 

You should have started a new thread including an attachment of your assembly that exhibits the behavior you describe.


-----------------------------------------------------------------------------------------
Autodesk Inventor 2019 Certified Professional
Autodesk AutoCAD 2013 Certified Professional
Certified SolidWorks Professional


The CADWhisperer YouTube Channel


EESignature

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

Post to forums  

Autodesk Design & Make Report