I didn't want to say that I can control porosity via stress, but that they are not independent (am I wrong anyway?). So, having a specific particle size distribution, the contact stiffnesses, the angle of friction, is it possible to get a specific value of porosity for the specimen? How can I do it with Yade?
Sorry if I continue on this point, but I am a little bit confused on it. Thank you very much, Chiara >----Messaggio originale---- >Da: bruno. [email protected] >Data: 08/12/2009 14.57 >A: <[email protected]. net> >Ogg: Re: [Yade-users] Compaction_phase/Triax > > >> I got that >> the final stage is achieved according to the sigmaIsoCompation (isotropic >> stress) value I choose. But in this case I cannot control the value of porosity >> (I mean, the porosity and the isotropic stress are not independent, but here I >> choose to get a specific value of isotropic stress that will correspond to a >> certain porosity). >No. This is a common mistake. You cannot control porosity via stress. >Well... you can, but it is not some realistic mechanics. >In reality, when you want to densify a sand, you don't apply a static >stress on it, you do something else (vibrations, height of >pluviation,...). The "elastic" change of porosity is very small compared >to the range of possible porosities. >Actually, the obtained porosity is a function of contact friction and >particles sizes distribution. > >> My question is: is it possible, with the second method >> (expansion method), to choose a final target porosity? In my case I would like >> to run the triaxial test starting with a certain value of porosity. >> >> >No. The two methods are exactly the same on this point. You impose a >stress, which has little - if any - influence on the final porosity. > >> Then I see >> that there is another flag called isotropicCompaction. Well, could you explain >> how it works? Since, actually it seems not working when I try to use it. >> >> >Somebody else introduced this flag. I don't remember why, sorry. If you >don't activate it, you will have isotropic compression anyway. > >Bruno > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >> Thanks a lot, >> >> Chiara >> >> >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~yade-users >> Post to : yade- [email protected] >> Unsubscribe : https://launchpad.net/~yade-users >> More help : https://help.launchpad.net/ListHelp >> >> > > >-- > >_______________ >Chareyre Bruno >Maître de Conférences > >Grenoble INP >Laboratoire 3SR - bureau E145 >BP 53 - 38041, Grenoble cedex 9 - France >Tél : 33 4 56 52 86 21 >Fax : 33 4 76 82 70 43 >________________ > > >_______________________________________________ >Mailing list: https: //launchpad.net/~yade-users >Post to : [email protected] >Unsubscribe : https://launchpad.net/~yade-users >More help : https://help. launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
