STEF - error

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  • Last Post 16 August 2018
Kellen.traxel posted this 14 August 2018

Hi, I am modeling single-layer laser additive manufacturing and get this error when running my model, which I have not had before when incorporating radiation into the model. I am wondering if there is a way to still incorporate radiation without using the STEF command.

 

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SandeepMedikonda posted this 15 August 2018

Kellen,

  How are you setting up your model in Workbench and Mechanical? It doesn't look like you are using the additive wizard?

Regards,

Sandeep

SandeepMedikonda posted this 15 August 2018

Also, I don't think this command is supported in the academic version:

Regards,

Sandeep

 

Kellen.traxel posted this 15 August 2018

Yes I do not have the additive package with my license, although I did install the extension when I first started running ANSYS. I am confused why it now is calling that function when I have not activated any aspect of that extension. To ensure this fact, I removed the extension from ANSYS and I am still getting the same error in my solution information file. Any suggestions? The problem is when I set up radiation on the top surface of my model. 

Kellen.traxel posted this 15 August 2018

If I suppress radiation, the model solves, albeit inaccurately.

SandeepMedikonda posted this 15 August 2018

Kellen,

  I am struggling to understand, how you are setting up your model and what you are doing. May be a few snapshots will help?

~Sandeep

Kellen.traxel posted this 15 August 2018

Here's my schematic and thermal model, when I run it I get the error that is shown in previous posts.

 

Let me know if I can send anything else

Kellen

SandeepMedikonda posted this 15 August 2018

Kellen,

  The error is very likely because of the unsupported version of your software.

Now, on a different note, how is this an Additive simulation? I don't see any printing or AM related commands. It looks to me that you are coupling a transient thermal analysis with a structural simulation.

  Please see this thread and on a workbench additive simulation.

Regards,

Sandeep

Kellen.traxel posted this 15 August 2018

Hi Sandeep,

I don't have access to the additive suite with my software version, and thus I am not using any AM-related commands (which is why I am puzzled by the error). Instead, I am using a moving heat flux in a transient thermal analysis and inputting the temperature distribution into the structural model to get the stress at each point in the simulation (for a single layer deposit of material). Is this an adequate approach for a single-layer simulation without using the Additive addin?

Even though I had previously installed the Additive ACT tool to see if my license could use any aspects, I never input any additive commands into my final model as I knew that it would not solve. I have since uninstalled the addin but am still getting the same error, so I am wondering if there migh be a quick fix, or I need to rebuild my model?

In the meantime, I ran a separate test simulation with a simple box radiating to ambient environment from 500K, and recieved no errors.

So this leads me to believe that the error is stemming from how my current simulation is setup. Any suggestions on debugging/my overall strategy?

Thanks

Kellen

SandeepMedikonda posted this 16 August 2018

Kellen,

  I don't think additive by default even writes our this command to the ds.dat file. I quickly ran an additive case that I had open and double checked this.

Now the command itself according to the manual is placed when:

You can use this command in the general preprocessor (PREP7) and in the Solution processor to specify the Stefan-Boltzmann constant in analyses using the radiation matrix method or the radiosity solver to model radiation.

So, it is being inputted from somewhere and the manual says that it can be input in one of these ways:

So, please check the possible causes. Note that it will be helpful to open the ds.dat file corresponding to this error file and look for its location. It might give you some insight. I am assuming that since you are using the MovingHeat ACT may be it is placed somewhere in the apdl code used by this extension, check if the inp files that this is using is calling for this command. Are you using the same ACT extension for the simple case as well?

Lastly, if you completely want to eliminate the possibility of your previous ACT doing something here. Go to this folder:

%appdata%\ansys

 and rename the folder with the version you are using, say, v191, to something else like v191.old. Then relaunch ansys and try again.

Hope this helps.

Regards,

Sandeep

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