How to exclude deleted elements from state files?

Altair Forum User

Hello,

I am currently using state files to run 2 consecutive simulations. Stress are exported for shell and tetra elements in a state file during the first simulation, and the second simulation include  the state file to consider an initial stress state for concerned elements. My problem is that I use failure laws in both simulations. During the first simulation, location and stress data are exported in the state file for all elements, including the deleted elements. However, these elements should not be included in the second simulation.

Is there a possibility to exlude deleted elements from the state file generated in my first simulation?

Thank you for your help,

Leo

Altair Forum User

Hi Leo,

 

When you set up consecutive simulations, .sta file contains the element ids and their coordinates and results. When the analysis starts the solver will only read the results for the id’s for the elements that are present in the model.

 

It will not consider the deleted elements. Hence no need to exclude the deleted elements.

Altair Forum User

Prakash,

 

Thank you for your answer. I'm going to have to double check that, but my first impression is that the solver exports every element in the model into the .sta file. The deleted element being only suppressed from the rigidity matrix, but not from the model, they are included in the .sta file. They are thus reintroduced in the rigidity matrix when running the secondary simulation using the .sta file.

 

If I understand your reply, the deleted elements should not be exported in the .sta file? Is there a specific option to ensure this?

 

Leo

Altair Forum User

Hi Leo,

 

Imagine you have four stages of analysis 1) forming 2)Forming 3) Trimming 4) Spring back.

 

 

Trimming is a pre-processing stage and the .sta file generated from this stage will be used for setting up spring back setup. But the results are read from the .sta file generated by 2nd stage of forming.

 

So, it doesn't matter if you have deleted elements in the 3rd stage of .sta file.

Altair Forum User

Hi Prakash,

 

In your example, the used .sta file would then be the one extracted in the 2nd stage, in which no elements are deleted? I have been able to run such simulations. However, here are some specificities of my simulation process which disable me from using this strategy:

I only use 2 simulation steps (1-impact; 2-bending).

A) 1-impact is run and .sta files are generated.

B ) I then load the original model in hypercrash, in which I have previously deleted all elements, and added #include XX.sta, to make somme modifications (parts addition, interfaces etc.).

C) 2-bending is then run using the modified model.

 

The problems are the following:

-Hypermesh is not usable because it does not support /INIBRI/ cards.

-In my case, all elements are read, in hypermesh or hypercrash, including the deleted elements, as the only pre-proc simulation step includes element deletion.

 

I currently use a matlab script to export a list of deleted elements, a tcl script to delete these elements in the model in hypermesh, and manually add the INIBRI card in the 0.rad file, which can be a bit sketchy.

 

Here are my apdate and system info:

 

 Altair Home: C:/Program Files/Altair/12.0

 

 Updates Information:

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

acusolve12.0

hwdesktop12.0

hwdesktop12.0.110

hwdesktophelp12.0

hwsolvers12.0

hwsolvers12.0.220

hwsolvershelp12.0

 

 Versions:

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

hgtrans.exe:                  12.0.110.40 (Mar 25 2014)

hm12.dll:                     12.0.0.85 (Feb  8 2013)

hmopengl.exe:                 12.0.110.40 (Mar 25 2014)

hst_ng.exe:                   12.0.110.40.500186 (Mar 25 2014)

hstbatch_ng.exe:              12.0.110.40.500186 (Mar 25 2014)

hstdss.exe:                   12.0.110.40.500186 (Mar 25 2014)

hvp.exe:                      12.0.110.40 (Mar 25 2014)

hw.exe:                       12.0.110.40 (Mar 25 2014)

hwmbdmodel.dll:               12.0.110.40 (Mar 25 2014)

hwplot.dll:                   12.0.110.40 (Mar 25 2014)

hwplot3d.dll:                 12.0.110.40 (Mar 25 2014)

hwpost.dll:                   12.0.110.40 (Mar 25 2014)

hwtext.dll:                   12.0.110.40 (Mar 25 2014)

hwvideo.dll:                  12.0.110.40 (Mar 25 2014)

hwx.exe:                      12.0.110.40 (Mar 25 2014)

templex.exe:                  12.0.110.40 (Mar 25 2014)

 

Please do not hesitate to ask for specifications about my simulations.

 

Leo

Altair Forum User

Leo,

 

`Do you have brick elements in your model?

 

What is the exact use case?

 

could you please let me know what exactly you trying achieve. 

Altair Forum User

Prakash,

In my model, I have brick, tetra, 3-node shell and 4-node shell elements. 

I am trying to analyze a structure that undergoes two consecutive loading configurations (stages):

-1st stage: imposed displacements of several points of the structure. At this stage, damage occurs through element deletion.

-2nd stage: some parts are added to the structure and an imposed compressive load is applied

The 2nd stage is dependant of the first. This is why I use state files.

I hope this helps. Unfortunately, I cannot give too much detail about the studied object, as it is confidential work.

Leo