Hello Bruno, In my model, When I am using Law2_ScGeom_CohFrictPhys_ElasticPlastic, it always occurs the errors. It cannot run. If I close the moment law, it is ok. If I open it, the error must be shown. If I use the traditional Triaxial-test and open the moment function, it is normal. If I delete the constrain along one axle and close the moment function, it is normal. If I delete the constrain along one axle and open the moment function, it is abnormal. I am so confused that. In the other hand, it only contains the elastic moment algorithms in Law2_ScGeom_CohFrictPhys_ElasticPlastic. whether it should be recovered if unloading. If do that, I think there will be some problem. The plastic rotation deformation may not be shown here. Do you agree with me? Could you possibly give your opinion? Thank you.
I have not tried the Cpm model. Because it may not be considered the cohesion at the re-contact point. It should be fit to the rock type perfectly. But in my model, the cohesion at the re-contact point must be implemented. So if I can solve the moment problem with your help, I think your model should be better. Cheers Liqing At 2010-10-21 00:34:12，"Bruno Chareyre" <[email protected]> wrote: > >> >> I am still investigating the cohesionlessMomentRotation. >> It is written in the sources files that this code has been "verified >> with the paper of Plassiard in GM". >> >> However, Plassiard considers in his paper "and in his thesis" only the >> rolling part of the relative rotation of particles (and thus only >> bending moment), whereas in the code rolling and twist part of the >> relative rotation are considered (and thus bending and twist moment). >There would be no contradiction here, if only it was possible to set >twist stiffness = 0 (so the law with bending and twist would "contain" >the law with bending alone). >For now, Ktwist=Kbending=Kr, so it is indeed not possible... > >> My question: is there a particular reason for that? What is the >> motivation of the person who wrote this code? I don't say that is bad >> or good, but I would like to have an idea about advantages and >> disavantages, and physical meaning for considering a twist moment. >> >As soon as there is a finite area of contact between the solids (i.e. >always), it makes sense to include twist resistance I think. The testing >has been done by Boon IIRC. > >By the way, I think rolling resistance, Ktwist!=Kbending, and other >features would be ideally implemented in >Law2_ScGeom_CohFrictPhys_CohesionMoment, which is now the cleanest, and >shortest code for moments. >Funky factors η, α, β, would be contained in a collection of Ip >functors, since they are not needed by the law itself, which just needs >4 stiffnesses, and the definition of maximum values for each force/moment. > >Any help on this task of unifying duplicates would be welcome. > >Cheers. > >Bruno > > > > >_______________________________________________ >Mailing list: https://launchpad.net/~yade-users >Post to : [email protected] >Unsubscribe : https://launchpad.net/~yade-users >More help : https://help.launchpad.net/ListHelp
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