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[Jan Stránský <question695734@xxxxxxxxxxxxxxxxxxxxx>]

Question #695734 on Yade changed:
https://answers.launchpad.net/yade/+question/695734

    Status: Open => Answered

Jan Stránský proposed the following answer:
Hello,

> no matter how I adjust the parameters (eg, epsCrackOnset,
relductility)

please provide the specific values

> The model seems so too 'brittle'. Is it because of the interaction
enlarge factor?

no, it is because of parameters / combination of parameters. interaction
enlarge factor is just one of them, not so important itself (IMO).

> I try to reduce the factor to 1.1, 1.05,etc and the model start to
have softening behavior but the elastic modulus has a huge decrease from
180 to 50 MPa. and I have to increase the young's to a very large value
in order to match the elastic modulus ...

'young' itself has nothing like "very large value". If the resulting macroscopic elastic modulus is OK, than the 'young' has just the right value.
Of course, changing young influences almost anything else and triggers need of recalibration of other parameters.

> but then I found excessive long hardening curve before the peak

hardening might be because "diagonal" interactions are already in nonlinear mode (plastic sliding), but damage is not yet present.
If you are interested, try different decreased values of sigmaT.

> readParamsFromTable(...,relDuctility= 1.1,...,epsCrackOnset=.025,...)

try relDuctility 2, 5, 10, 100, 1000, ...
relDuctility=1.1 should result in very brittle material :-)
0.025 seems relatively large (but depends on your needs)

Concerning calibration, have a look at [1], section 3.3

cheers
Jan

[1]
https://www.researchgate.net/publication/45194493_Cohesive_Particle_Model_using_the_Discrete_Element_Method_on_the_Yade_Platform

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