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How to interpret error message? "For plasticity models, raise: ETAN > Ex/100"

How to interpret error message? "For plasticity models, raise: ETAN > Ex/100"

How to interpret error message? "For plasticity models, raise: ETAN > Ex/100"

(OP)
I'm trying to run a non-linear dynamic study.
I've tried to run it a few times now, playing with solver settings, but am having no luck getting past this error.
I'm not sure how to interpret this error message:

Quote (Simulation)

Solution failure in Step>1, it could be due to:
The solution may be at a buckling or limit point, i.e., displacements grow large under constant forces.
If so, for force control or contact problems, this is the end of the solution (check out the response graphs).
The solver numerical difficulties:
1. For Plasticity models, raise: ETAN > Ex/100

This message regarding "ETAN" seems to indicate some problem with the solver calculating the tangent modulus of (one? both?) of my materials (there are only two materials, images of both S-S curves below). I am not sure exactly what is meant by raising it to "Ex/100"; how do I interpret "Ex"? Right now I'm running a linear-static study now to make sure there are no other issues that I'm missing (and also to optimize my mesh in case that is an issue).


What I've tried:
I've tried lowering the max time increment and raising the number of adjustments in solution settings>time increment; I also raised the max incremental strain, dropped the Singluarity-elimination-factor to 0, and I even tried raising the convergence tolerance limit from .001 to .005 in advanced settings.
I've tried both Large Problem Direct Sparse and FEEPlus solvers, and I've tried both NR and MNR iterative techniques.
At the request of my VAR, I smoothed out my S-S curve definition in the plastic region to eliminate "valleys" in the plastic region (see screenshots below) but this did not help.

Even after all that, I still get the same error message.
It’s not clear to me what the problem is at this time step (the few times I've tried to run it, it always fails between .21-23 pseudo-time, which takes about 3 hours to solve each time). Looking at my load profile there isn't any dramatic change in the loading here, it's a linear progression up to around ≈ .410 which is the first semi-release of load.

I can't share model, but I have attached some screenshots of error message and some screenshots that may help.
If you need more specific information let me know and I will share as much as I can.

Thanks!!









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