Hello, Dear(s) Cervenka

My name is Ingrid.
I'm writing you with the aim of obatin your help in the next model:

I am simulating one model of beam-column of reinforced concrete with UHPFRC. I did the calibration both of the material of reinforced concrete as of UHPFRC obtaining good results when compared with the experimental curves. However, in the model of materials using interface material or master/slave, I have convergence error. I think that is caused by the interface properties.

I have been changing diferents parameters, however I have this problem yet.
Could you help me, please?