Hi

I need your help again. Thanks in advanced again.

I have been reading the manual for a while and I still don't understand how it works for stresses in local material orientation. I defined a local material orientation which has xy rotate 45 degree clockwise. In element output, I have direction=yes for stress in integration point and averaging at nodes. Now I am trying to display stresses in local material orientation without any success until I tried using direction= NO in element output. 

https://help.3ds.com/2020/english/dssimulia_established/simacaecaerefmap/simacae-m-resresultoptions-sb.htm?contextscope=all

*Orientation, name=Ori-1
0.707106781186547, -0.707106781186547, 0., 0.707106781186547, 0.707106781186547, 0.
3, 0.

*Element Output, directions=YES
E, FV, MISES, PEEQ, S, TEMP, VOIDR, POR
*Element Output, position=AVERAGED AT NODES, directions=YES
E, S

Here are some results comparison between direction=yes (Left figure) and direction=no(right figure).

The first 2 figures are stresses at integration points before transformation. You can see both result are displayed at global coordinates and the results are the same between direction=yes and direction=no.

The 2nd 2 figures are stresses at integration points after transformation using menu of result option->transformation->select material orientation. Now you can see using direction=No (right figure), I can get stresses displayed at local orientation and it is different from left figure using direction=yes.

the 3rd 2 figures are nodal stress after transformation. The nodal stress are obtained using averaged at nodes. You can see all the nodal stress result are always displayed in global orientation and they are the same. I cannot never get nodal stress in local orientation.

Here are questions I have which might help me understand :

1. Why only using direction=No, I can get stress displayed at local material orientation? Even using direction=yes, the displayed result is still in global orientation even after transformation. From below manual, it says by default element-based result are displayed by default at local material orientation. And using direction=Yes, material orientation is written into odb.

The manual:

DIRECTIONS

This parameter applies only to Abaqus/Standard and Abaqus/Explicit analyses.

Set DIRECTIONS=YES (default) to write the element material directions to the output database. Set DIRECTIONS=NO to indicate that the element material directions should not be written to the output database.

https://help.3ds.com/2020/english/dssimulia_established/simacaecaerefmap/simacae-t-restransform.htm?ContextScope=all

2. after transformation, the xy triad sign at the bottom left becomes local material orientation. Is it correct?

3. why averaged nodal stress is always displayed in global orientation? 

4. using the below python script, how do I know the stress is from local or global orientation?

thisframe = frame.fieldOutputs['S'].getSubset(elementType='C3D8P',position=INTEGRATION_POINT)

5. after defining local material orientation, the input initial stress are automatically defined in local material orientation. Is it correct?

Thank you again.