Re: [Yade-users] [Question #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Christian Jakob posted a new comment: ScGeom is enough in that case. ScGeom6D is needed for bending and twisting at the contact point, not for rolling resistance. Someone should explain the the difference in documentation ... https://yade- dem.org/doc/yade.wrapper.html?highlight=updaterotations#yade.wrapper.Ig2_Sphere_Sphere_ScGeom6D -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Chareyre posted a new comment: The answer to which Ig to use is: the one imposed by the contact law. Different laws have rolling friction, some will use 3Dof, others will use 6Dof. Allthough I admit one easily gets lost in the many contact laws (I removed some of them last week, btw), I don't see something missing in the documentation on this precise question. Feel free to suggest something to add if I overlooked. Something missing, however, is a table summarizing the features of all the laws. Bruno On 06/07/12 08:35, Christian Jakob wrote: https://yade- dem.org/doc/yade.wrapper.html?highlight=updaterotations#yade.wrapper.Ig2_Sphere_Sphere_ScGeom6D -- ___ Bruno Chareyre Associate Professor ENSE³ - Grenoble INP Lab. 3SR BP 53 38041 Grenoble cedex 9 Tél : +33 4 56 52 86 21 Fax : +33 4 76 82 70 43 You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 wangxiaoliang posted a new comment: Hi Jakob, as you would like to use rolling resistance, u have at least 4 DOFs ( 1 normal, 2 shear and 1 roll), so which Ig (Interaction Geometry) do u use, ScGeom or ScGeom6D? -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 wangxiaoliang posted a new comment: I am trying to add a rolling physics using Ip2_MomentMat_MomentMat_MomentPhys Law2_SCG_MomentPhys_CohesionlessMomentRotation However, rolling parameters have no effect to the macroscopic response too, like u. -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Christian Jakob posted a new comment: - either you did not set parameters in right syntax (like i did) - send the part(s) of your code to see if it is correct - or parameters are set to a value, where you do not see any effect - send the values you set - or everything is ok, but rolling parameters have no big effect in your case ... (see also the paper luc proposed to read - #1) - simulation inspection may help ... -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Luc Scholtès posted a new comment: Hi Jacob, For the 2nd point, you may want to have a look at the paper from Plassiard: http://www.springerlink.com/content/16688jw766197204/ (I can send it to you if you cannot download it). For the 1st point, I cannot help... I though that combining 2 constitutive laws was possible but, actually, I never tried... Luc -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Christian Jakob posted a new comment: Thanks for the fast answers. @Luc: download successful ... @jduriez: Here, Ip2_FrictMat_FrictMat_MindlinCapillaryPhys() has two major drawbacks : - it uses material data of FrictMat type, whereas you want to use CohFrictMat.. - it computes interaction data of MindlinCapillaryPhys(), while your law needs MindlinPhys.. MindlinCapillaryPhys and MindlinPhys are working equal, when Law2_ScGeom_CapillaryPhys_Capillarity is not active. However, linking these values with the rounded feature of the grains is a task too difficult for me... What do you mean with that? For further explanations: I perform pour cone tests to get the natural repose angle (ca. 30 degree for well rounded sand). While increasing friction parameter I can get 24-25 degree as maximum repose angle, so I thought including rolling friction will help me getting the right repose angle to verify my model ... -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Chiara Modenese proposed the following answer: Hi Jacob, As for point 1: I introduced the rolling friction in HM Law some time ago. Please have a look at the documentation, in particular at: https://yade-dem.org/doc/yade.wrapper.html?highlight=includemoment#yade.wrapper.Law2_ScGeom_MindlinPhys_Mindlin.includeMoment https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Ip2_FrictMat_FrictMat_MindlinPhys.eta https://yade-dem.org/doc/yade.wrapper.html?highlight=krot#yade.wrapper.Ip2_FrictMat_FrictMat_MindlinCapillaryPhys.krot @Luc: It is not about combining two contact laws but everything can be dealt with inside one contact model (resistance to rolling is a separate additional feature, in fact). As for point 2: It is entirely up to the calibration procedure. Chiara -- Chiara Modenese, BSc MSc DPhil(PhD) Candidate in Engineering Science Department of Engineering Science Parks Road, Oxford, OX1 3PJ, UK email: chiara.moden...@eng.ox.ac.uk website: http://www.eng.ox.ac.uk/derg/people/chiara-modenese-1 On 6 Jun 2012, at 14:11, Christian Jakob wrote: New question #199585 on Yade: https://answers.launchpad.net/yade/+question/199585 Hi, I want to model a sand with Hertz-Mindlin-Contact law and rolling friction. 1. Is it possible to do so in yade and if yes, how? I tried to combine a material with rolling stiffness and hertz model: ... #define material: id_SphereMat=O.materials.append(CohFrictMat(young=young_modulus,poisson=poisson_ratio,density=rho_p,frictionAngle=angle,alphaKr=roll_stiff)) ... InteractionLoop( ... [Ip2_FrictMat_FrictMat_MindlinCapillaryPhys()], [Law2_ScGeom_MindlinPhys_Mindlin()] ), ... but this seems to have no effect on behavior of the particles. 2. What would be a good value for lets say a well rounded sand? Has anyone experience with rolling stiffness? Thanks in advance, Christian -- You received this question notification because you are a member of yade-users, which 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 You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Christian Jakob posted a new comment: @chiara: Thanks, will ... #define material: id_SphereMat=O.materials.append(FrictMat(young=young_modulus,poisson=poisson_ratio,density=rho_p,frictionAngle=angle)) ... InteractionLoop( ... [Ip2_FrictMat_FrictMat_MindlinCapillaryPhys(krot=roll_stiff)], [Law2_ScGeom_MindlinPhys_Mindlin(includeMoment=True)] ), work in my case? -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Chiara Modenese proposed the following answer: On 6 Jun 2012, at 15:10, Christian Jakob wrote: Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Christian Jakob posted a new comment: @chiara: Thanks, will ... #define material: id_SphereMat=O.materials.append(FrictMat(young=young_modulus,poisson=poisson_ratio,density=rho_p,frictionAngle=angle)) ... InteractionLoop( ... [Ip2_FrictMat_FrictMat_MindlinCapillaryPhys(krot=roll_stiff)], [Law2_ScGeom_MindlinPhys_Mindlin(includeMoment=True)] ), work in my case? It should, indeed. Mind that you can also define eta parameter if you want to set a maximum plastic moment. Chiara -- You received this question notification because you are a member of yade-users, which 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 -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 jduriez posted a new comment: However, linking these values with the rounded feature of the grains is a task too difficult for me... What do you mean with that? I meant that I can not point a good value of the rolling stifness, only from the information that the sand is well rounded (as you asked) -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Status: Answered = Solved Christian Jakob confirmed that the question is solved: ok, thanks everybody! -- You received this question notification because you are a member of yade-users, which 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 #199585]: how can i simulate rolling friction?
Question #199585 on Yade changed: https://answers.launchpad.net/yade/+question/199585 Christian Jakob confirmed that the question is solved: Thanks Chiara Modenese, that solved my question. -- You received this question notification because you are a member of yade-users, which 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
