concrete02 convergence problem

[apapaso]

Hello!

I am experimenting with different concrete materials on a cantilever beam under static compression and lateral cyclic pushover.
When I try to use concrete02, the lateral analysis collapses (error -2 or -3) at the first step.
In contrast, materials 01 and 04 work perfectly, up to quite large deformation (15% drift or so, monotonic or cyclic).
It seems that the problem is related to the material stiffness, because when I try larger ec0 values I can get some analysis steps complete.

values used:
uniaxialMaterial Concrete01 1 -33000 -0.0022 -5180 -0.010 -------------------------> without problem
uniaxialMaterial Concrete02 1 -33000 -0.0022 -5180 -0.010 0.1 2600 1700000 ---> analysis crashes
uniaxialMaterial Concrete02 1 -33000 -0.0035 -5180 -0.010 0.1 2600 1700000 ---> a few steps completed (drift 0,008%)
uniaxialMaterial Concrete04 1 -33000 -0.0022 -0.010 31E6 2600 8E-5 0.1 ---------> without problem

reinforcement:
uniaxialMaterial Steel4 1 5E5 2E8 -asym -kin 0.01 20 0.90 0.15 0.066 500 0.90 0.12

(apparently the materials are EU C25/30 and B500c in kPa, m, kN)

The model is a cantilever beam of 1.5m, and I have tested FB element, fiber section from 0.25χ.40m up to 0.5χ0.5m, with reinforcement from 3cm² up to 10cm² per side, and axial load from 0 to -2000kN, pushover steps from 0.001 to 0.00001m.
The problem is exactly the same in all cases.


*Edit: I apologise for the (now corrected) errors in the initial message...

[parsaparvanehro]

Do you find the solution and the reason?