Surface Traction Error

[Andrea P]

Good morning,

I am currently doing a project in my university, and for that project I need to use ABAQUS and more particularly use Surface Traction to simulate Shear Forces.
However, everytime that I am using the python script where I create the Surface Traction, Abaqus just stops.
I get many error messages:
- On my computer :

Error: ABQcaeK.exe /rank 0 / thread 0 encountered a system exception 0xC0000005 (EXCEPTION_ACCESS_VIOLATION)​

GUI detected errore while waiting for ipc connection to close​

ABAQUS/ABQcaeG rank 0 received the SIGABRT signal​

Therefore I tried to use the super computer from my university and I still get the same problem with those error messages:
ON the abaqus.rpy file:
No error

On the abaqus_acis.log file:
????????
*** Warning (spaacis/src:FACE_ALREADY_IN_SHELL)
An attempt was made to place a FACE in a new SHELL before removing it from its existing SHELL
????????
many times without error messages in the end

Also, I noticed that everytime that I am opening the GUI, and copy my python script to the CLI (command line interface), it doesn't work. But if I do only half of the code, open the assembly module and then use the code for surface traction, it is working perfectly!

I hope that someone can help me with this problem.

Best regards,

AP

 

[FEA way]

It seems that there’s an error somewhere in the code and that the script tries to redefine the face of shell element instead of just referring to it for the definition of load.

 

[Andrea P]

Yes, I also thought of that, I tried to create my surface traction, directly on the gui (using the same vertices + same surfaces) and When I use the code from the .jnl file, it also doesn't work.
Would you have any advise on how should I proceed ?

 

[FEA way]

Check parts of the code that operate on shell element faces. Some of them may use incorrect commands. Verify them with Scripting Reference Guide.

 

[Andrea P]

Thank you for your comment, I will try this
Also, what I forgot to mention is that I used the exact same surfaces for other load types (pressure) and it is perfectly working ! It just doesn't work when I create Surface Traction

 

[FEA way]

This type of load requires specific definition. Make sure that it's done correctly by your script. Apart from the surface and magnitude you have to specify load type label and 3 components of the traction vector direction:

*DSLOAD
surf_name, load_label, magnitude, 1_dir, 2_dir, 3_dir

 

[Andrea P]

Thank you for your answer !
Yes I also looked online in the ABAQUS Scripting Reference.
Here is the code I used to construct my shear force:

myModel.SurfaceTraction(createStepName='StepName',
directionVector=(
myModel.rootassembly.instances['Instance1'].vertices.findAt((0,h,0),),
myModel.rootassembly.instances['Instance1'].vertices.findAt((0,0,0),)),
distributionType=UNIFORM, field='', localCsys=None,
magnitude=magn_Shear_Force,
name='Shear_Force',
region=myModel.rootassembly.instances['Instance1'].surfaces['LoadSurface'], traction=GENERAL)

The assembly are correct, the vertices can be found (I checked in the CLI), the magnitude is equal to 1 and the region is also correct because I used the exact same region for another pressure and it was working fine.
So after reading your comments, I really do not understand where should I specify the directions (except if that is the directionVector).
I also really need to apply shear and not concentrated force because shear will always be parallel even to the deformed shape of the Instance

 

[FEA way]

By directions I meant the directionVector argument but it’s only relevant for General and Shear type of traction while here you are using the Uniform one.

 

[Andrea P]

So I removed the argument "distributionType=UNIFORM" (which doesn't change anything because the default value is uniform) but I still get the problem..
Do you maybe have any other ideas ?

Also here is how I defined the surface:
myModel.parts['Part'].Surface(name='LoadSurface', side1Faces=myModel.parts['Part'].faces.findAt(((0,h/2,b/2), )))

 

[FEA way]

To ensure that the surface is defined properly you can enter this in CLI (Command Line Interface in Abaqus/CAE) and then highlight the newly created surface in viewport.

 

[Andrea P]

This is what I get and this is exactly the surface where I need the shear to be !
Also, I partition and make holes in the part after this. So finally, the part should look at this:

So it seems my part is consituted of many shell elements. But it wasn't a problem until I used this command