Seemingly incorrect shear stress-strain curve

[2443631711@qq.com]

Dear stko team
I have established a very simple model to simulate sand liquefaction, and it seems that the shear stress shear strain curve of post processing is not satisfactory. Is the result option selected by me for post processing incorrect?

The shear strain shear stress curve should look like this (fig1), but my results don't seem quite right

I have attached my model below. Could you help me check where the error occurred?

[STKO Team]

The PDMY uses a different convention for 2D (plane strain) stress components:
It gives a 5-components vector like this: [S11, S22, S33, S12, InternalVariable]
But STKO assumes it's a 5-component vector as in Shells (Yes, in OpenSees, Shells gives 5 components because the S33 is zero in shells)


So you should extract it like this:

settings with stress full.png (23.49 KiB) Viewed 163 times

This is what I got:

result_with_restraints.png (30.94 KiB) Viewed 163 times

[2443631711@qq.com]

Therefore, the rules for extracting results should be extracted in the order of [S11, S22, S33, S12, InternalVariable] in the opensees wiki, not in the order marked in stko σ 12, right?

Thank you for answering my question. I always thought there was a problem with my model

[STKO Team]

Therefore, the rules for extracting results should be extracted in the order of [S11, S22, S33, S12, InternalVariable] in the opensees wiki, not in the order marked in stko σ 12, right?

Yes, but only for this material (and its variations PIMY 02 03 etc...), just because they don't follow the rule of all other materials (and of course STKO is not aware of that)