please follow the discussion, at least taken simple test individually.
also, it’s not about syntax only, the old and new.
Sorry synt it’s sometimes hard to me to understanding. I’m following the discussion and I have some of the concepts still fresh. I’m interested because I didn’t enter into the hardening aspect of the model. I have done many individual tests. I simply don’t understand how could you expect the model to deliver plasticity if in the inp you show there seems to be no Hardening definition?
are you sure for Modified MC material model in latest version of CalculiX?
commonly a user material have different output parameter, like plastic strain or damage index. However, Modified MC models is not documented regarding this request.
it can lead to a bit confuse when mixed between Standard MC and Modified MC material models.
well the output of previous version (v2.15) given clear in stress and strain plasticity, but not available for PEEQ request.
No issues with plastic flow. If you have defined the Hardening correctly and you are looking at the right output most probably you have not reach the Yield surface yet.
I would take simple test individually with this parameters.
*MATERIAL,NAME=MOHR-MB-30
*ELASTIC
31000000000, 0.111
*MOHR COULOMB
36.0,36.0
*MOHR COULOMB HARDENING
3.0E6,0.0
3.1E6,0.01
3.2E6,0.02
3.3E6,0.03
3.4E6,0.04
3.5E6,0.05
3.6E6,0.06
*SOLID SECTION,ELSET=Mohr,material=MOHR-MB-30
I think I see what you both might be doing wrong. You are probably looking at Principal Stresses individually instead of elaborating the Cohesion value.
Try to apply formula to see if you should be yielding or not.
Refer to ccx manual 6.8.11 Mohr-Coulomb plasticity. in case of any doubt.
again, you do mixed between Standard MC and Modified MC, here we are discussed for later ones.
my previous screenshot is only an example ones related to strain history (i…e worst principal), as shown by 8/31 in CGX
I must have had too much coffee this morning.
Yep, that’s why I thought posting the formula could be usefull.
Good morning,
My masonry model should operate within the elastic range, with a maximum compression stress of -2.00 MPa [analytically calculated] and tensile stresses close to 0.00; that would be expected. The stress results with the traditional MC model fit within that range without any issues.
I have been gradually increasing the plasticity values to possibly exaggerated levels to force the monitoring of plastic deformations and verify the functionality of the Modified MC. However, since I haven’t observed any plastic deformation, I have questioned my model.
I have tried using the plasticity values you suggested, and unless I made an error, no type of plastic deformation is being monitored:
However, with the traditional MC material, I do get plastic deformations. Another point for discussion is whether they may be more or less coherent, but apparently, it may seem reasonable:
Using the syntax of the traditional MC material, I obtain results that, in my opinion, are more coherent. I would need to refine the mesh and analyze mesh convergence, but as an initial model, it could suffice, and unless you advise otherwise, I will continue using the traditional MC.
Thank you very much for your help and expertise.
Damián
that’s why i mention in early correction. Standard MC have no problem, but Modified MC has. The problem for Modified MC model is treated as elastic in latest CalculiX distribution (v2.21 and v2.20), this is not normally as i have frequently done in previous versions (v2.15).
that’s okay, i’m having a bit confused also due to problem in solver itself of CalculiX latest distribution.
Then, even though there’s a new MC model with its own keywords, it might be worth reporting on GitHub since the old model is still available and thus should work properly.
right, normally it should be working expected as previous distribution, hopefully it can be fixed for next versions.
I’m looking at this plasticity controversy but meanwhile I noticed there are some areas on your model that are disconnected and mess the convergence.
Not sure if that is an error when exporting.
Perhaps that’s the reason why the plastic deformations aren’t symmetric, when in principle, some symmetry is expected. The initial idea is to use a HARD contact between the inner arch and the vault since they are not connected.
Ultimately, I’ve modeled it as a composite solid since I couldn’t achieve convergence; that’s likely the explanation. I greatly appreciate your input. I’ll review the model to see how I can address the issue.
Thank you very much for your help and expertise.
Damián