Thermal Stress analysis by using MES on Mechanical 2015

[Anonymous]

I plan that a simple thermal stress analysis is performed by using MES and the results of transient thermal analysis.

In ASMECH 2014, I successfully finished the transient thermal analysis.　　After that I performed the MES time dependent stress analysis using the result of transient thermal analysis.

  And I plan the same analyses on ASMECH 2015R1, the transient thermal analysis can be performed. But the stress analysis by using the results of the thermal analysis cannot be performed. I got a following error message from ASMECH 2015R1;

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** Error in making [C:\Users\amatsuda\Documents\ThermalStress\ThermalStress.ds_data\2\ds_map.ltt], it might fail by:
(1) Previous job is not from transient Heat
(2) File is damaged
(3) File is not resident in the directory

** Job started : 2014-10-14 21:28:34
** Job finished : 2014-10-14 21:28:35
** Total elapsed time : 1 (seconds)
!! Program aborted !

-------------------------------------------------------------------

What's my issue of this simple thermal-stress analysis on ASMECH 2015? (Same analysis can be performed on ASMECH 2014.)

Regards,

Amatsuda.

[zhuangs]

I tested Mechanical 2016, first ran DS1 and then ran DS2, the model works fine.

In Mechanical 2015, there might be a bug related to mapping ds.ltt file from DS1.  Mechanical 2016 has some fix on this.

-Shoubing

[Anonymous]

Thank you very much for your reply!

Would you log this issue of 2015R1 to the development team for fix? I hope so.

At the same time, I and our team will wait for the release of 2016.

Best regards,

Amatsuda

[Andrew.Sartorelli · Accepted solution]

Shoubing is correct, there is an issue with the ltt file that gets generated in the latest release. There is an extra linebreak of all things that is preventing the analysis from correctly mapping the results. Here the is the suggested workflow until a fix is implemented:

1. Run the first design scenario as normal
2. Go into the ds_data directory for that design scneario and open up ds.ltt in Notepad
3. Remove the blank line between line 1 and line 3
4. Open a new Command Prompt window and change to the directory where your file is located (cd "C:\Directory\Directory\ThermalStress.ds_data\2\")
5. Next run the analysis using the following command "C:\Program Files\Autodesk\Simulation 2015\apak4.exe" ds -run

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[Anonymous]

Hi andrew,

Thanks a lot!
I traced your proposed workaround.
The MES analysis can be successfully performed and finished.

I am looking forward to that this issue will be fixed.

Thank you again.

Amatsuda

[AstroJohnPE]

Hi Andrew,

If the problem is located in the transient heat transfer analysis file DS.LTT located in design scenario 1, why would you need to run the MES analysis in design scenario 2 from a command prompt? Why not run the MES analysis from the interface?

Usually, running the analysis from a command prompt is done to bypass a step that the software normally does. For example, if you edit one of the database files (located in the ds.mod folder) to include something that the software does not do directly (such as a pressure based on an equation and the coordinate of the elements), then you need to run the analysis from a command prompt; otherwise, running the analysis from the software first does a "check model" which overwrites the databases and destroys the manual changes you made. I cannot imagine that running the analysis in DS2 will "undo" the manual changes made to the .LTT file in DS1. But stranger things have happened.

[Andrew.Sartorelli]

Hi John,

I agree, one would think you should be able to make a modification to the LTT file and then run the analysis through the interface, however that does not work. I'm unsure of what specifically prevents the model to be run through the interface after making the required modification. The workaround that development provided to the support team specified that running from the command prompt was necessary.

Glad to see you are part of the Autodesk Expert Elite program now 🙂

[arizawilmer]

Hi last week this problem almost make me cry. I do simulation of welding process (WPS simulation) over oil storages tank to check if the method generates stress over the shell

7 days trying to solve the problem thinking that was my model and the end was a internal error.

What i discover was that the problem to not run in the interface directly without running the prompt is a unit conversion problem.

This after doing a check over the model in the MES simulation.

When we are going o have access to Autodesk Simulation Mechanical 2016 or to a hot fix to solve this problem?

[zhuangs]

V2016 might be avaialble in a couple months.  You can also contact the corresponding sales person for some information.

-Shoubing

[Andrew.Sartorelli]

Hi Wilmer,

You could try running the 2016 beta, I believe the program will last until when 2016 launches but you can check on the beta forums.
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