Re: [Yade-users] [Question #694574]: ViscoEl contact normal stiffness kn in the source file is not consistent with that in the documentation
Question #694574 on Yade changed: https://answers.launchpad.net/yade/+question/694574 Status: Expired => Open Yuxuan Wen is still having a problem: Thank you Jerome! So do you mean that a constant factor such as 2, or pi, doesn't really affect the results of simulation? Because the fundamental equation in DEM Fn=kn dl1 is also not strictly proved and is just a approximation. Kind Regards, Yuxuan -- 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 #697763]: The equation in documentation and the source code is not consistent
Question #697763 on Yade changed: https://answers.launchpad.net/yade/+question/697763 Yuxuan Wen posted a new comment: Sorry, I am using the 2nd option in the documentation. I typed "3rd" in the original question, which is not correct, the 2nd option is what I meant to type. -- 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
[Yade-users] [Question #697763]: The equation in documentation and the source code is not consistent
New question #697763 on Yade: https://answers.launchpad.net/yade/+question/697763 Hello, I am trying to use a viscoelastic contact model to do the simulation. In the documentation, it shows there are 4 options to assign the parameters and I choose to used the 3rd option, where kn1, ks1, kn2, ks2 are assigned. The documentation shows that the equivalent normal stiffness is kn=2*kn1*kn2/(kn1+kn2), as shown in: https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_ViscElPhys_Basic If normal and tangential stiffnesses (kn, ks) and damping constant (cn,cs) of each particle are precised, the equivalent stiffnesses and damping constants of each contact made of two particles 1 and 2 is made A=2*a1*a2/(a1+a2). However, I checked the source code of viscoelastic model and the kn in the source code is: kn=kn1*kn2/(kn1+kn2), the factor "2" is missing comparing to the documentation. The equation in the source code is shown in line 309 of https://gitlab.com/yade-dev/trunk/-/blob/master/pkg/dem/ViscoelasticPM.cpp I am confused with this contradiction between the source code and the documentation. If you know which is the correct one, I wonder if you can help me, thank you! Regards, Yuxuan -- 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 #697744]: Increase particle radiues
Question #697744 on Yade changed: https://answers.launchpad.net/yade/+question/697744 Status: Open => Answered Jan Stránský proposed the following answer: The first error says that it expects a number, but you provide a numpy.ndarray > r= odeint(model,P[3],t,args=(P[0],P[1],P[2],P[3],P[4],)) > b.state.radius = r[1] maybe here, r[1] might be something different than you want. Concerning radii of cylinders, the condition "if isinstance(b.shape, Sphere)" is true also for cylinder, since Cylinder is inherited from Sphere [1]. Use b.shape.__class__ == Sphere instead to detect just spheres (and not derived classes too). Cheers Jan [1] https://yade-dem.org/doc/yade.wrapper.html#shape -- 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 #697479]: Spheres swelling
Question #697479 on Yade changed: https://answers.launchpad.net/yade/+question/697479 Status: Open => Answered Jan Stránský proposed the following answer: body.state.mass = value body.state.inertia = (x,y,z) # 3 principal values > each iteration? set iterPeriod to 1 Cheers Jan -- 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 #697615]: displacement vs friction graph plotting
Question #697615 on Yade changed: https://answers.launchpad.net/yade/+question/697615 Status: Open => Answered Jan Stránský proposed the following answer: So "friction at interface" is friction force? In your O.engines, you have no collider, therefore no collision detection and no forces. Have a look at [3]. Cheers Jan [3] https://yade-dem.org/doc/user.html#base-engines -- 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 #697548]: Simulating the time-dependent behavior of single grain
Question #697548 on Yade changed: https://answers.launchpad.net/yade/+question/697548 Jan Stránský proposed the following answer: > Do we have a creep contact model for the single agglomerate under constant load in Yade? My instructor thinks the creep contact model is the most important. There are some models including viscosity, have a look [1] (I myself do not use and know them almost at all). Also there were some models developed, which were not put to the Yade source code [2], you can search question history. Yes, the contact model is of course important. But the solution approach too. E.g. if the simulation is not feasible to compute, then the best model is "useless". > Is there a script for " long-term aging of concrete"? Or there is only the short-term of concrete to use Cpm. No. I doubt there is any example of "long-term" behavior, since (as discussed), Yade is used for "short-term" scenarios. >> You could maybe use some implicit integration scheme, but I am not sure how >> it would work for "non-continuous" phenomenons > Could you please explain one more time for me, and I understand it like this: > in Yade default uses explicit time integration and I can also change it into > implicit integration, but maybe not good for the non-linear situations. or > only uses explicit time integration? Is it due to too much computer cost? Yes, Yade default (I would say almost "built-in") time integration is NewtonIntegrator, using explicit time integration, requiring "very short" time step. Not usable for "long term" simulations. But you can use other integration, e.g. there is RungeKuttaCashKarp54Integrator [3], or some substepping, or event-driven approach, or many of the ideas are out of scope of Yade.. > Yade is my first choice, if it is really not suitable, I may try other DEM software. I am not sure if Yade and DEM is the way to go.. Yade is nice that it is open source and you can "add anything". Assuming non-negligible time costs and some programming. So it also depends on your time, background etc. Now you know some basic ideas, maybe you can ask new specific questions [4] for the sub-topics (model, integration scheme, general discussion about feasibility, ...). My conclusion: from Yade (and DEM in general), I see the biggest problem the "long term" behavior. Cheers Jan [1] https://yade-dem.org/doc/yade.wrapper.html#constitutive-laws [2] https://answers.launchpad.net/yade/+question/255780 [3] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.RungeKuttaCashKarp54Integrator [4] https://www.yade-dem.org/wiki/Howtoask -- 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
