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eee26
Posts: 1
Registered: ‎10-23-2013
Message 1 of 2 (301 Views)

Mesh Failure mid-simulation

301 Views, 1 Replies
10-23-2013 08:21 AM

Howdy,

 

I'm running a static simulation of a small assembly and it runs fine with no refinements. However, after the first refinement is made it produces a mesh error: "Mesh failed: Face failure: Cam-Cert:1." The mesh is not incredibly tight, so I'm not sure why it's failing after only one iteration. It also gives me an improper constraint, material, or mesh error if I just try to run it with 0 refinements after that. Further, when I replace all of the contacts surrounding a shaft with bonded contacts, it seems to run just fine (though inaccurately). Any idea what could be going on? Am I missing something really obvious? Is this some idiosyncracy of Inventor?

Attached is a compressed folder containing the assembly and all associated parts. The simulation is in the assembly. Unfortunately, I had to remove the FEA data as it put me over the data limit.

 

Any help would be much appreciated; thank you.

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henderh
Posts: 649
Registered: ‎06-07-2007
Message 2 of 2 (274 Views)

Re: Mesh Failure mid-simulation

10-24-2013 05:43 PM in reply to: eee26

Hi eee26,

 

  There are two issues that could be causing strange results (otherwise it's a very interesting simulation and setup correctly in my opinion):

 

1)  The ID of the washer isn't making physical contact with the shaft.  If you change the ID from 16 to 15mm, we no longer see the "soft springs" error message.

2)  The material Oilite has a very small Young's modulus (1E-4 MPa) defined.  This is likely beyond what can be used for the linear analysis assumptions.  Poisson's ratio of zero is right at the borderline too.

 

  I can reproduce the issue of the mesh failing with adaptive meshing and convergence, which I've sent on to Development as 1508172 to look into.  Even if we use copper instead of Oilite, this problem still occurs.  As you've noticed, once we get into this state and change the number of h-refinements back to zero, we get an error about inconsistent mesh.  I suspect it's because we're trying to re-use the bad mesh.  If you change the mesh settings (e.g. average element size back to default 0.1) it will dirty the mesh and not re-use it next time we ask for a solve.

 

Thank you for bringing this to our attention, and I apologize for the inconvenience it's causing.

 

Best regards, -Hugh

 

  



Hugh Henderson
Simulation QA Engineer
DLS

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