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problem with bolt connection and cylindrical coordinates

4 REPLIES 4
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Message 1 of 5
AndreMarcic6025
486 Views, 4 Replies

problem with bolt connection and cylindrical coordinates

Hello,

 

I try to simulate a bolted connection in a segment of a round assembly and i get the following error message:

 

Error occurred with module: C:\Program Files\Autodesk\Simulation 2014\srunx.exe

 

I prepared a test model with two pipe flanges bolted together. I modelled a quarter "slice"

 

If i keep the global coordinates and fix the cut faces, everything is fine

If i define cylindrical coordinates for the parts, i get the error.

 

If i keep the cylindrical coordinates and skip the screws, everything is fine again.

 

what is going wrong?

 

Andre

4 REPLIES 4
Message 2 of 5

 

Hi Andre,

 

Is there anymore information other than "Error occurred with module"?

 

Is there any connection (no pun intended) between the bolt and the cylindrical coordinate system? Are any of the nodes of the bolt assigned to the cylindrical coordinate system?

 

In the event that there is a bug, you need to find a way to make the model without the bolt or without the cylindrical coordinate system. What are you using the cylindrical coordinate system for? Some images or sketches may be helpful.

Message 3 of 5

Hi John,

 

Please find attached the model setup and the error message (the file is normally named "ds.l")

 

What is the meaning of "no pun intended?

 

There is no difference when i assign the cylindrical CS to all parts or only to the two volumes.

Once I switch the CS for all parts to global, the analysis is running.

For a test I only changed the CS and didn't touch anything else and i got a solution which was nonsense due to the incorrect constraints, but without errors and warnings.

 

Andre

Message 4 of 5

Hi Andre,

 

Thanks for the image and .L file.

 

The key question is this: what are you using the cylindrical coordinate systems for? I see a force applied in the axial direction. Since you have modeled 1/4 of the full model, you have a 90 degree sector with the cut faces normal to the X and Z directions. So you can use X Symmetry and Z Symmetry without assigning the cylindrical coordinate system. I see no reason to be using a cylindrical coordinate system.

 

The different coordinate systems in the FEA Editor are used with loads and constraints. They have nothing to do with the geometry, material properties, results, and so on. Also, it would be unusual to assign a coordinate system to an entire part. Normally, a few surfaces or nodes are assigned to a coordinate system so that the loads or constraints act in a direction other than X, Y, Z.

 

In the Results environment, coordinate systems are used to transform the results from one system to another. In your case, the Y direction and axial direction are the same, so you would not need a coordinate system to look at the axial displacements or axial stresses (Stress Tensors > YY). But you could use a cylindrical coordinate system to view the results in the radial and hoop directions instead of the X and Z direction.

 

But more importantly, Wikipedia says a pun is a form of word play that suggests two or more meanings, by exploiting multiple meanings of words, or of similar-sounding words, for an intended humorous effect. In this case, bolts are used to connect parts together. But I was asking if there was a correlation, something relevant, or something in common between the bolts and cylindrical coordinate system; in other words, is there a connection between the bolts and coordinate system.

 

Sorry for my less than humorous sense of humor.

Message 5 of 5

Hi John,

 

No worries about your sense of humor....

 

My real problems looks of course different than the one you see. In reality i want to simulate a segment of 20 degrees (and the model is so large that i cannot simulate 180 degrees)

 

"example" is only my test case to check if it is only a problem of my complex model or something else.


The 90 degrees model should give me the same results in global or cylindrical coordinates if i adjust the constraints to the CS.

 

Andre

 

 

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