Re: [Yade-users] [Question #628632]: Modeling particle breakage in YADE
Question #628632 on Yade changed: https://answers.launchpad.net/yade/+question/628632 Status: Open => Solved Tina Asia confirmed that the question is solved: Thanks Jan, I have got a desired porosity (about 0.27) packing using randomDensePack and growParticles. Thus, there is no need to write a function compressing irregular shapes. But, this packing always ‘explodes’ because of particles' penetrationDepth. I have searched some questions in LaunchPad, but those methods all failed. As my new question was posted here: https://answers.launchpad.net/yade/+question/630281 Thanks for your patience. Regards, Tina @ Yade -- 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 #630468]: CPMMat Stiffness formulation versus other cohesive laws
Question #630468 on Yade changed: https://answers.launchpad.net/yade/+question/630468 loiseaurare posted a new comment: Hi Robert, Thanks for the answer on the Aeq quantity, I suspected something like that but was unsure... Well, you've asked my second question, I also wonder why in the formulation of this contact law he chose to use the minimum of the two. Maybe the CPM mat was meant to be used for materials with an homogeneous size distribution in the particles ? Or to model granular material at a scale where particles do not represent material particles, and thus might not need a specific size distribution. Then the difference of radius between two given spheres could be neglected ? However, since in this formulation the li~ equals Aeq over li, I am right in assuming that the li distance corresponds to ri ? Cheers, Manon -- 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 #630468]: CPMMat Stiffness formulation versus other cohesive laws
Question #630468 on Yade changed: https://answers.launchpad.net/yade/+question/630468 Status: Open => Answered Robert Caulk proposed the following answer: Hello Manon, >And that is where I get lost. I do not understand the dimension of this Aeq over li quantity. I think that in >the way it is expressed here, it actually has no dimension, where it should have a m dimension ? You've found a typo in the DEM background/Václav's thesis. It should read "A_eq = pi * min(r1, r2)^2" since that is in fact what is used in the concrete model [1]. The unit of stiffness is force/displacement or in SI, N/m. So in this case, the units work out since E Pa * A_eq m^2/ l_i m -> Pa*m = N/m. I am curious though why he chose to use min(r1, r2). This seems like it would skew the interaction stiffness distribution left resulting in a less stiff specimen. At the end of the day, we always calibrate the micro-properties to experimentally observed macro behavior. In this case, we'd just have to compensate for that skewed distribution with a different combination of micro-parameters. Idk maybe someone can shed light on that. [1]https://github.com/yade/trunk/blob/dafe23a8e34ab581edc0425d28290fc5ba591ce8/pkg/dem/ConcretePM.cpp#L315 -- 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 #630468]: CPMMat Stiffness formulation versus other cohesive laws
New question #630468 on Yade: https://answers.launchpad.net/yade/+question/630468 Hi everybody, I have been browsing through the description of different cohesive contact laws, and I am now trying to understand the differences between JCFpmMat, CPMMat and cohFrictMat. My question is on the formulation on the contact normal stiffness Kn, I read in the JcfPMMat and CPMMat description that this is defined by the function kn = 2*EcRaRB/(Ra+Rb) Ec being the "Young modulus" parameter introduced in each of those contact laws, that actually does NOT define macroscopical youngs modulus. Ra and Rb being the radiuses of the two interacting particles. In Dr Smilauer thesis, this formulation is introduced in a more general way, stating that kn in the algorithm is computed with the formula : kn = k1k2/(K1 + K2) => kn = E1l1~*E2l2~/(E1l1~+E2l2~) . Assuming that E1 and E2 are the same between the two particles, this yields kn = E(l1~*l2~)/(l1~+l2~) It is then precised in the thesis that for 'The most used class computing interaction properties Ip2_FrictMat_FrictMat_FrictPhys uses ̃ l i~= 2ri. " I think that Cohfrictmat and JcfPMat also use this formulation, am I correct ? Then the concept of the equivalent cross section is introduced, as being another way to define the li~ length. "Some formulations define an equivalent cross-section A eq , which in that case appears in the li~ term as Ki = E i * l i~ = Ei Aeq/li . Such is the case for the concrete model (Ip2_CpmMat_CpmMat_CpmPhys) described later, where A eq = min(r 1 , r 2 ) " And that is where I get lost. I do not understand the dimension of this Aeq over li quantity. I think that in the way it is expressed here, it actually has no dimension, where it should have a m dimension ? If anybody can give a hint, I will appreciate ! Thanks in advance, Manon -- 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 #266828]: How to reset the repulsive forces at the beginning of a compression test
Question #266828 on Yade changed: https://answers.launchpad.net/yade/+question/266828 loiseaurare posted a new comment: Well, Thanks Bruno and Jerome, I understood this issue. I am still working on understanding how Yade fully works. that's why I read archives ! Regards, -- 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
