Learning Forum

[Evgenii_K]

Happy New Year and Merry Christmas everyone.

I simulate reinforcement in concrete, the calculation ends without errors, but when stresses and strains in reinforcement are displayed, the reinforcement is displayed in a strange way:

[John Doyle]

It looks like a graphics bug. There are a few bug reports on reinforcement results plots.
One in particular (#524449 - Result display for reinforcement shows bad element outline), report a fix for R2022-R1.
I would recommend taking the model into MAPDL to confirm its just graphics.

[Evgenii_K]

Thanks, I figured it out with MAPDL too, everything works
I have a question about the convergence of the Menetrey-Willam model solution, I have my own methods that I use, but they do not always work and I would like to have a reliable method that will work flawlessly.

[Erik Kostson]

Hi

Concrete modelling can be difficult to get convergence - one way we have is to use the material solution parameter (MSOL) for the Menetrey-Willam.



See slide 10 in the demo I have made for modelling concrete using the Menetrey-Willam model.
Also this link shows and explains how to use this :
4.10. Geomechanics (ansys.com)

Of course it is not possible to always get convergence with this and one can not guarantee that it will always converge, but it will at least aid convergence and be probably a better option then the default option, especially when we are at total failure of the structure and beyond (post failure response, e.g., softening).
All the best

Erik

[Evgenii_K]

Hi @ekostson, I read your article and it came in handy for me, but this article is not exhaustive and there are many questions about setting up nonlinear control, I have already worked with the settings and am ready to discuss.

[Erik Kostson]

Hi

I do not have much to add/discuss. Except that the nonlinear controls in mechanical (as shown in the image above) I never change so in that demo it is all program controlled, as shown below (not recommended to change those, at least those related to the convergence criteria, e.g., force convergence).

As I said before, from my little experience modelling concrete the most critical parameter that can make the biggest difference improving convergence is the msol material solution option in ansys, as seen in that demo, and for much larger and complex structures. With the msol we can look at failure and even go way post failure of the structure (see image below), so I would recommend to use that. That is all I can say, and again there might of course still be some challenges with convergence with nonlinear analysis (even with msol), especially for concrete, and unfortunately there is no special setting that will make it always solve/converge, if there was a fea software would be using this settings of course as default :).


That is all I can add,
all the best

Erik