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UMAT with steady state transport step in Abaqus  


charters05
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I am trying to run a simulation for the rolling of a solid disc. For the material definition, I want to use a UMAT subroutine. However, as soon as the Steady State Transport step begins, the run aborts with the following error in the message file.

***ERROR: USER SUBROUTINE UMAT_SST IS MISSING

I couldnt find any mention of a subroutine called UMAT_SST in the documentation for Abaqus. Neither was any such error mentioned in the manuals. Any help would be appreciated greatly.

I have attached the .inp files and the sample UMAT for a Neo-Hookean model in a zip archive. To the simulation run the axi inp first and then the sst inp.

Thank You
Feby

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Jorgen
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I wrote an UMAT_SST a few years ago, before it was made an official feaure. I just looked at the Abaqus Docs for version 2019, and I dont see any info about UMAT_SST.
It appears that that they did not officially release UMAT_SST subroutines.

-Jorgen

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charters05
Posts: 5
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Joined: 4 years ago

Do you mean to say that UMAT with Steady State Transport problems is still under development by Abaqus? I found a line mentioning the following in the Analysis Procedure (Abaqus 2017) manual corresponding to Steady State Transport :

Most material models that describe mechanical behaviour (including user-defined materials) are available for use in a steady-state transport analysis.

This seems to suggest user-defined materials is already supported by Abaqus. On a more theoretical side, UMAT with SST would include additionally the convective derivatives. Am I correct?

Is there any documentation or technical papers that you referred to write the same?

Thank You
Feby

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Jorgen
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I dont know if it is still in development. I did not see UMAT_SST as one of the subroutines that are supported by Abaqus/Standard. If it is not in the manuals then it is likely an unsupported feature. I recommend that you contact Abaqus support to find out the status and if you can obtain documentation for the feature.

I received that type of documentation when I worked on implementing a UMAT_SST, but that was a few years ago.

-Jorgen

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charters05
Posts: 5
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Joined: 4 years ago

Thank you, Jorgen.

I got the confirmation that UMAT_SST is not officially supported by an Abaqus employee on the Simulia Learning Community.

Sigh.

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