I have been trying to use the new plastic shell feature in FLAC3D to model a reinforced concrete (RC) slab. However, I’ve encountered difficulties in defining the Mohr–Coulomb plasticity parameters for RC slabs.
As we know, the behavior of an RC slab is usually described in terms of member forces; shear, bending, etc. But when using the plastic shell in FLAC3D, the model requires material-based plasticity parameters (e.g., cohesion, internal friction angle).
I attempted to find reliable references to convert RC slab strength into equivalent Mohr–Coulomb parameters, but without success. The closest approach I found was on Plastic shell modelling in FEM-Design 23 for steel and reinforced concrete | StruSoft
, where concrete and reinforcement are modeled with separate strengths rather than combined into a single set of plasticity parameters.
My question is:
Do you have any suggestions or references on how to convert RC slab member strengths into equivalent material strength parameters (such as Mohr–Coulomb cohesion and friction angle) suitable for use in the FLAC3D plastic shell model?
or the plastic shell in FLAC3D is recommneded only for mass concrete? or just check crack of RC members not plastic hinge formation? I think that it is hard to find the case to model mass concrete in shell.
Another question:
In FLAC2D 8.0, the nonlinear liner behavior was supported through the pmtable (moment–thrust diagram), which defined the plastic limit of the liner in terms of member forces (axial force and bending moment).
However, in FLAC 9.0, I cannot find this feature. Instead, the program now seems to rely only on material-based strength criteria (e.g., Mohr–Coulomb, von Mises, etc.).
My question is:
What was the reasoning behind removing the pmtable approach in favor of material-based failure criteria? This seems like a significant shift, as the pmtable offered a more direct way of modeling member capacity.
Regards.