[Yade-users] [Question #159705]: Is it a bug ? mass won't update after desity changing
New question #159705 on Yade: https://answers.launchpad.net/yade/+question/159705 hi, I found it kind of unreasonable about the mass calculation of body(sphere and box). I don't know whether it have been posted. If yes, plz ignore this. I am trying to increase the timestep by assigning a large density to particles, so-called density-scale. However, I found the mass of body won't update when a new density assigned. Maybe it is a bug, at least unreasonable. As far as I found, the mass of body is calculated only in Shop.cpp, saying only available in the initialize of body. So the calculated mass is right only if the body is declared with given materials. Otherwise, it will be calculated according to the default value(1000. in my current version) and won't update even if you change the density. regards, Lin ZHANG -- 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 #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed: https://answers.launchpad.net/yade/+question/159705 Status: Open => Answered Anton Gladky proposed the following answer: Do you need to change a density during simulation? Anton On Tue, May 31, 2011 at 9:21 AM, Lin Zhang wrote: > New question #159705 on Yade: > https://answers.launchpad.net/yade/+question/159705 > > hi, > I found it kind of unreasonable about the mass calculation of body(sphere and > box). I don't know whether it have been posted. If yes, plz ignore this. > I am trying to increase the timestep by assigning a large density to > particles, so-called density-scale. However, I found the mass of body won't > update when a new density assigned. Maybe it is a bug, at least unreasonable. > > As far as I found, the mass of body is calculated only in Shop.cpp, saying > only available in the initialize of body. So the calculated mass is right > only if the body is declared with given materials. Otherwise, it will be > calculated according to the default value(1000. in my current version) and > won't update even if you change the density. > > regards, > Lin ZHANG > > -- > 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 #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed: https://answers.launchpad.net/yade/+question/159705 Chareyre proposed the following answer: If you want to change mass, you can change mass directly. You are right: if you change density of a material it will no affect existing bodies. I think the current behaviour is reasonable. Bruno -- 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 #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed:
https://answers.launchpad.net/yade/+question/159705
Lin Zhang posted a new comment:
hi Anton,
I want to increase the density to get a higher timestep. In fact, I solved it
by updating mass and inertia manually. but consider the py script below:
sp=pack.SpherePack()
sp.load('sample.spheres')
sp.toSimulation()
it is a common method to load sample into simulation. the particles'
mass will be initialized with default density value and won't change if
the density is modified later.
Lin
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Re: [Yade-users] [Question #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed: https://answers.launchpad.net/yade/+question/159705 jduriez proposed the following answer: Hello, I understand your surprize, but I have the feeling that such things are quite common in Yade. Let say you have a simulation with bodies and interactions, and at one time you decide to change frictionAngle of (material of) bodies, which should change frictionAngle of interactions also. But existing interactions will *not* be updated... Because their properties are computed only once, when they are created. The choice is surely to not compute all the things (that are supposed not to change) at each time step. So, if you meet such cases, you have to do the job by yourself (as in TriaxialCompressionEngine for the previous example of frictionAngle). In your case, you'll have to do a loop on the bodies to recompute their mass according to their (new) density. -- 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 #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed: https://answers.launchpad.net/yade/+question/159705 Status: Answered => Solved Lin Zhang confirmed that the question is solved: Thank you, Anton, Bruno and jduriez. I should have read all your posts before my last post. Thank you all. -- 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 #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed: https://answers.launchpad.net/yade/+question/159705 Chareyre posted a new comment: > it is a common method to load sample into simulation. the particles' > mass will be initialized with default density value and won't change if > the density is modified later. In case it's still not clear: you don't need a loop after that to change all masses. Simply define density _before_ loading the spheres. -- 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 #159705]: Is it a bug ? mass won't update after desity changing
Question #159705 on Yade changed: https://answers.launchpad.net/yade/+question/159705 Yade Guide posted a new comment: Hi there! As an automated bot, I've gone through your question and found a few relevant threads that might interest you. Feel free to explore these topics further by checking out the links provided below. Title: "problem replacing TriaxialStressController with PeriTriaxController" Jesse discusses using PeriTriaxController for simulating gravity with cloud of clumps or periodic packing, addressing issues with makeclumpcloud and changing the periodic controller. Jan suggests increasing maxStrainRate to speed up compression, which worked after setting it to 1e10 and running 500,000 steps. Bruno offers further suggestions like decreasing 'compressor.mass' and checking if O.dt=PWaveTimeStep() is accurate for clumps. https://answers.launchpad.net/yade/+question/656214 Title: "Changing properties of spheres causing problems." The user encounters slow deposition and compression when modifying sphere properties (density, Young's modulus, Poisson's ratio, friction angle) in a gravity deposition followed by uniaxial compression example. The issue occurs when using non-default material properties, causing the compression to start at 80,000 iterations or more. Jan Stránský suggested checking the time step (O.dt), which depends on material stiffness. https://answers.launchpad.net/yade/+question/248023 -- 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
