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I have the following problem with the second model of the tutorial "STKO E-Learning Course - Modeling of a Reinforced Concrete Frame Structure (webinar in English)", it gives me an error regarding the value of the concrete "Error: the fracture energy (Gf = 0.03) is too small or the characteristic length of the element (lch = 100) is too large.
The minimum Gf to avoid constitutive rollback is 0.0283".
I have used different values for the meshing, reducing the lch and the gf, but the error persists. I also applied a solution that proposes deactivating the self-regulation, but convergence problems are obtained. I attach the file and the images of the errors. I hope you can help me.

I don't have this problem with the model downloaded from the website. did you modify something? can you share your modified model?

Hi, Please also check if you modify the meshing (coarser mesh when compared to the default one from webinar) of the model this can happen.

attached worked model

You modified the material properties and made the fracture energies to small.
that's what the error is telling you

Could you tell me what properties to modify and what energy value to use to avoid the error.

STKO Team wrote: ↑

Tue Jun 25, 2024 8:13 am

You modified the material properties and made the fracture energies to small.
that's what the error is telling you

Could you tell me what properties to modify and what energy value to use to avoid the error

Hi, Please refer to the following article (page. 11, Equation.30). Theory of the material is discussed in the article. You can get the idea about the fracture energy settings.

Petracca, Massimo, Luca Pelà, Riccardo Rossi, Stefano Zaghi, Guido Camata, and Enrico Spacone. "Micro-scale continuous and discrete numerical models for nonlinear analysis of masonry shear walls." Construction and Building Materials 149 (2017): 296-314.