Abaqus file mesh import

[jessica....@arcor.de]

Hi all,

I am trying to use an Abaqus (.inp) file for the mesh.
It is generated by Hypermesh, that could also export the mesh as Radioss, Optistruct, Actran, Ansys, LsDyna, Madymo, Marc, Nastran, Pamcrash, Permas or Samcef formats.

If I try to run Moose, an error message occurs, saying "negative Jacobian"...

The error seems to originate from the mesh, as the exodus file (created with "--mesh-only") opened in Paraview is showing a really strange mesh. Attached you can find the Pictures of how it should look like (Model in Hypermesh) and how it actually looks like in Paraview, as well as an very simple test model (1 Block with sidesets for boundary conditions).

I tried already to replace the sidesets with nodesets, but that makes no difference.

Maybe the numbering of the elements is not in the right order?

Does anyone have an idea how to solve this problem?


Thanks a lot in advance,
Jessica

[Peterson, JW]

Our Abaqus mesh reader was created by reverse-engineering several example input files rather than to any particular spec.

So... it's possible that you are using an element type that we have not encountered before or that we simply have the connectivity wrong for... I will take a look.

--

John

[Jessica Freymark]

Thanks a lot!

Could you please send me an abaqus input file that Moose can read? Maybe we can try to find a solution how to change our file to the same format...

[Peterson, JW]

On Thu, Sep 8, 2016 at 2:03 AM, Jessica Freymark <jessica....@arcor.de> wrote:

Could you please send me an abaqus input file that Moose can read? Maybe we can try to find a solution how to change our file to the same format...

Attached.

--

John

[Peterson, JW]

On Thu, Sep 8, 2016 at 8:22 AM, Peterson, JW <jw.pe...@inl.gov> wrote:

On Thu, Sep 8, 2016 at 2:03 AM, Jessica Freymark <jessica....@arcor.de> wrote:

Could you please send me an abaqus input file that Moose can read? Maybe we can try to find a solution how to change our file to the same format...

I reduced your mesh to a single element with 4 nodes: 

**

** ABAQUS Input Deck Generated by HyperMesh Version  : 13.0.110.31

** Generated using HyperMesh-Abaqus Template Version : 13.0.110

**

**   Template:  ABAQUS/STANDARD 3D

**

*NODE

       132,  600.0          ,  0.0            ,  2000.0         

       182,  598.27739913794,  0.0            ,  1769.5104070409

       185,  408.99541091115,  0.0            ,  1821.7696522459

       571,  590.66553532516,  169.8943819332 ,  2000.0         

*ELEMENT,TYPE=C3D4,ELSET=auto1

1,       571,       182,       132,       185

I think I figured out the problem: Note the spaces in between the y component values and the comma for each node.  Our reader was not expecting any spaces there, and therefore assumed it was a 2D point and simply did not read the z-component of these points.  Removing the extra spaces causes the file to be read correctly.

A quick fix for you is to simply remove the extra spaces from your file.  I will eventually fix our reader to be more robust in situations like this.

Sorry for the inconvenience...

--

John

[Jessica Freymark]

Thank you so much!!! It's working now!

[Peterson, JW]

On Thu, Sep 8, 2016 at 9:53 AM, Jessica Freymark <jessica....@arcor.de> wrote:

Thank you so much!!! It's working now!

OK, good.  The fix has been merged to libmesh master:

https://github.com/libMesh/libmesh/commit/c4d03e6d7b8eaac95ecc93995c0bbe0bf66156fa

but it will be a little while before the version of libmesh in MOOSE is officially updated.

-- 

John