Problem with static structural analysis

[holmesss]

Hello,

I recently started using femap 11.1 and I've been having a problem for the past two weeks that I can't solve.

I have a simple assembly of two parts that I exported as a parasolid ( .x_t) from solidworks.
When I run the FEA static analysis in solidworks simulation , it works with no errors.
When I open the parasolid assembly in femap , and when I run the analysis I get a fatal error 9031 (ERRPH1) .
I tried reducing the size of the mesh, I ended up with more errors.
I tried to check element quality ,I ended up with missing surfaces.
Only one of the two parts is causing the problem,is there a way or program to fix the part?It's really frustrating.
Any ideas why the same assembly works on solidworks simulation but not on femap ?

Thank you very much.

 

[rb1957]

have you looked in the f06 file, there's more description about the error codes there.

how have you joined your two parts together ?

another day in paradise, or is paradise one day closer ?

 

[holmesss]

Yes I connected the two parts.
Even when I delete the part that's not causing any problems , and run analysis with only the part causing the problem , i still get the same error.

in f06 there's a message "nogo encountered in subdmap semg."

But I really don't understand the problem.
Maybe the part has edges or faces causing problems for femap ?
Can you recommend a tolls or a way to check my part and fix it ? (But again,the part performed normally in solidworks)

thanks a lot for your reply

 

[rb1957]

"subdmap" ? ... doesn't sound like a simple linear run.

how's the connection between the pieces modelled ? are the connections inline (like a hinge) ? are the connections springs ? If a model is supported only by springs it'll fail (constraint 1 node in 6dof to take out rigid body motion)

you think the problem is in one piece ? can you run the model with only the piece you think works ? can you run the other piece on it's own with the connects remodelled as constraints ? what if you "weld" the pieces together (change the element nodes, yes?) ?

a pic might help ?

another day in paradise, or is paradise one day closer ?

 

[holmesss]

Yes the problem is in one piece, because if I run the good piece alone , it works. While when I run run the "faulty" piece alone it fails.

Also when I mesh the faulty piece , I can read that the mesher skipped a few degenerate surfaces.And they also say that there are duplicate faces somewhere.(Eventhough when I check the model,I can't find the duplicate faces).

I will attach the file in a bit.

 

[holmesss]

here's the assembly

 

[rb1957]

i don't know what a .x_t file is, and neither does my computer ... how about a screen shot ?

another day in paradise, or is paradise one day closer ?

 

[holmesss]

Ok sorry, here's a sldasm file.
And a screenshot would not help I guess since the problem is inside the part I guess or something in the configuration of my femap.

 

[Naffoussi]

Try the File / Rebuild and list here the error messages.
If there are some duplicate surfaces then their IDs will be printed in the message box.

Seif Eddine Naffoussi, Stress Engineer

http://www.Innovamech.com

33650 Martillac û France

 

[holmesss]

@compositecurves well after meshing I get the following : "Tet mesh was created but problems were reported " "...4 nodes causing the problem"

If I look into the comment box : >>> Warning : Found duplicate face : 96 2168 97
>>> Warning : Found duplicate face : 96 2214 2168

These two sets of 3 numbers each , are coordinates or IDs ? So there's 2 faces or 6 faces causing the problem ?How can I delete them ?Or should I leave some of them ?

 

[holmesss]

Because if I do Geometry->Solid>Remove Face and Type "96" for example or even "96-97-2168" they say "0 face was selected"

 

[rb1957]

duplicate face for a tet would suggest the three numbers are node IDs.

have you tried the coincident node check ?

can you view these nodes or elements (using "show entities") ?

another day in paradise, or is paradise one day closer ?

 

[holmesss]

No I can't see them in "show entities" .
It's really complicated it seems.
Do you think I should not use parasolids ?
What's the best file format for FEMAP ?(I'm new to femap as you can see).

Thanks a lot for your time btw

 

[rb1957]

if it exists in the modfem, it'll show in "show entities" .... have you checked the boxes "transparent highlight" and "label with ID". you can also use "list, model"

another day in paradise, or is paradise one day closer ?

 

[Naffoussi]

I've already encountered this kind of issue but forgot how I solve it.
Export a ".dat" and import it in a new Femap then see what errors will be shown.
Otherwise, you should clean up your geometry before meshing it. There are a lot of capability under Femap to solve geometry issue.
Use the meshing toolbox to identify small edges and surfaces...

Regards,

Seif Eddine Naffoussi, Stress Engineer

http://www.Innovamech.com

33650 Martillac û France

 

[rb1957]

"I've already encountered this kind of issue but forgot how I solve it." ... damn ! don't you just hate that !

another day in paradise, or is paradise one day closer ?

 

[holmesss]

Hope you remember ! Because I think I'm hopeless with this assembly .

 

[Naffoussi]

Could you drop the CAD if it is not confidential? or just the part causing problem?

Seif Eddine Naffoussi, Stress Engineer

http://www.Innovamech.com

33650 Martillac û France

 

[rob768]

I read the X_T model and it looks like your model has some cavities (no pun intended). The crown has some holes, near the edges. You will need to fix that but i don't think this can be done automatically. The error most likely is in the program determing/scanning the geometry.

 

[Kwan]

I've run into this before. The 3D model probably has "weird" geometry that is causing issues. You need to change the accuracy of the model in solid works. I'm not sure how to do this but there is a setting to do this. The model will likely fail at the bad geometry and then you can fix the issue and export. Hope this helps.