Re: [Yade-users] [Question #668213]: How to make sure that the interaction between spheres and containers is frictionless
Question #668213 on Yade changed: https://answers.launchpad.net/yade/+question/668213 Status: Open => Answered Jérôme Duriez proposed the following answer: Hi, Honestly I did not go in details through your whole post :-) but I'd still make the following comments 1- I think you could consider that in YADE / DEM, properties for a single entity (a Discrete Element) do not exist outside mass and inertia. Then, the question is more about : are the soil-container contact properties really different from the soil-soil ones ? And if yes, does it really matter to define one external layer of interactions (the soil-container one) that has very different properties than all other interactions in the bulk ? 2- Checking the shape of interacting bodies can be done in the source code of one single Ip2 if you need to. You got one example at [*] 3- Are you then interested in shear stress (original post) or normal force and normal stress (post #2) ? 4- I still think material flowing outside a experimental or numerical device is a problem :-) If I understood correctly, I would just extend my plates if I were you (you may give a look to SimpleShear FileGenerator from YADE graphical user interface) Jérôme [*] https://github.com/yade/trunk/blob/4167bd08a304167375ac38bca441aa30e8d4d673/pkg/dem/Law2_ScGeom_CapillaryPhys_Capillarity.cpp#L101 to L103 -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #668315]: mininum timesteps after change to calculate the convergene accuracy
Question #668315 on Yade changed: https://answers.launchpad.net/yade/+question/668315 Status: Answered => Open Luc OGER is still having a problem: this is not exactly my case: for me, the spheres are only subjected to a gravity field : no external compression at all and I am awaiting for a "quasistatic equilibrium" before changing and the imposed change of the gravity is of the order of 10-4 which meant that the calcul of the 'new unbalancedForce is only changed immediatly by 10-6 order of magnitude before changing more after some time i have tried gravity (0.01,0 ,0) then (0.02,0,0) and looked at the immediat difference and after few timesteps -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #668191]: The spheres explodes at the first iter
Question #668191 on Yade changed: https://answers.launchpad.net/yade/+question/668191 Bruno Chareyre proposed the following answer: I incidentally found that my above statement was incorrect. "makeCloud is not generating overlaps" is only true under the assumption of consistent input by user. It is admitted, for instance, that min should be smaller than max... I hope it helps. Bruno -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #654435]: Yade breaks terminal
Question #654435 on Yade changed: https://answers.launchpad.net/yade/+question/654435 Bruno Chareyre posted a new comment: I agree with Persio, we don't want to go through all example scripts to remove qt() stuff. It would be clearly a regression. Possibly, this hack could be applied selectively based on the graphic card manufacturer or anything that we believe is the source of the problem. Since this bug seems difficult to reproduce and (is that true?) is not yet reported on 18.04 it does not sound critical to me. Bruno -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #668315]: mininum timesteps after change to calculate the convergene accuracy
Question #668315 on Yade changed:
https://answers.launchpad.net/yade/+question/668315
Status: Open => Answered
Bruno Chareyre proposed the following answer:
Hi,
The following assertion is wrong, and consequently I don't understand the
question:
"When I tilted the gravity field, the full simulation needs 'some timesteps"
before giving a new correct unbalancedforce calculation"
If gravity is changed the unbalanced force is different and correct
instantaneously, even after 0 iteration.
Proof below.
Cheers
Bruno
Yade [1]: tt=TriaxialTest()
Yade [2]: tt.generate('test.yade')
Yade [3]: O.load("test.yade")
Yade [4]: O.run(1,1)
Yade [5]: unbalancedForce()
-> [5]: 0.036382094190800705
Yade [6]: typedEngine('NewtonIntegrator').gravity=(100,0,0)
Yade [7]: unbalancedForce()
-> [7]: 0.18847344871180757
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Re: [Yade-users] [Question #668315]: mininum timesteps after change to calculate the convergene accuracy
Question #668315 on Yade changed: https://answers.launchpad.net/yade/+question/668315 Status: Answered => Open Luc OGER is still having a problem: Dear Jerome, When I tilted the gravity field, the full simulation needs 'some timesteps" before giving a new correct unbalancedforce calculation (otherwise the threshold test is immediatly still valid); checking every 500 steps will produce the same problem of initial recalculation of the new equilibrium of all the forces. so this is the reason of the waiting of 5000 timesteps BEFOREchecking the unbalance, but it looks like that it is too small when I check the quality of the results! so your comment about "you can use plenty of other values instead of 500" is what exactly I was looking for : how to approach the correct order of magnitude without doing a lot of test runs depending of the number of spheres, the friction coefificent, the stiffness and so on doing that at random is right now a waste of time. -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #668315]: mininum timesteps after change to calculate the convergene accuracy
Question #668315 on Yade changed: https://answers.launchpad.net/yade/+question/668315 Status: Open => Answered Jérôme Duriez proposed the following answer: Hi, I did not completely get you :-) This being said, assuming your concern is about the line https://github.com/yade/trunk/blob/master/doc/sphinx/tutorial/03 -oedometric-test.py#L51 (and the comment L50) that is reflected in https ://yade-dem.org/doc/tutorial-examples.html#oedometric-test: This line and the choice and of a 5000 step number is only motivated by the fact unbalancedForce is not a correct equilibrium (in the sense resultant force on particles ~ 0) indicator at the start of a simulation where no / low contact forces exist. Then some iterations (5000 here) are performed regardless of unbalancedForce() to allow some non-zero contact force / non-zero stress state appear in the numerical sample, making unbalancedForce() useable from this point onwards. I'd advice you try to skip this "if O.iter<5000: return " kind-of exception in your general workflow (once your simulation exhibits some stress state). Note running a (unknown beforehand) number of DEM steps until equilibrium can also be done with while unbalancedForce() > yourThresholdValue: O.run(500,True) # you can use plenty of other values instead of 500 -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #667493]: How do we generate fibres and randomly distribute them?
Question #667493 on Yade changed: https://answers.launchpad.net/yade/+question/667493 Status: Open => Expired Launchpad Janitor expired the question: This question was expired because it remained in the 'Open' state without activity for the last 15 days. -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #668286]: save in txt.file a packing of spheres
Question #668286 on Yade changed: https://answers.launchpad.net/yade/+question/668286 Status: Open => Answered Luc Scholtès proposed the following answer: Hi Jacopo, Changing the "young" and "poisson" in the material functor will change the stiffness of the newly created contacts only. If you want to change the stiffnesses of the existing ones, I believe that you have to loop over the interactions and modify the attributes of their Ip2_FrictMat_FrictMat_FrictPhys (for i in interactions: i.phys.kn=newValue). You should be able to do that but you should also consider opening a new question since this one is not related anymore to the initial one "save in txt.file a packing of spheres". Luc -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #668378]: Histogram of crack orientation
Question #668378 on Yade changed: https://answers.launchpad.net/yade/+question/668378 Status: Open => Answered Luc Scholtès proposed the following answer: Hi Luis, The 3 coordinates of the contact normal is what you are looking for. They give the coordinates of the unit vector normal to the crack plane. The crack plane corresponds to the surface perpendicular to the branch vector joining the particle centers (it is located right at the location where the breakage occurs, as indicated by the 3 coordinates of the contact point). Based on the unit vector, you should be able to orientate the cracks in a reference frame (most probably, the same reference frame in which the vector coordinates are defined). If you come up with a clean postprocessing script doing what you want, would it be possible to share it with the community? I believe it would be of great benefit for JCFPM users. "nrg" gives the energy released by the breakage of the bond. This energy corresponds to the elastic energy stored in the bond before it breaks (in both normal and shear springs). Luc -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
