Re: [Yade-users] [Question #694664]: Tiny particles don't react with the wall
Question #694664 on Yade changed: https://answers.launchpad.net/yade/+question/694664 Leonard confirmed that the question is solved: Thanks Jan Stránský, that solved my question. -- 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 #694664]: Tiny particles don't react with the wall
Question #694664 on Yade changed: https://answers.launchpad.net/yade/+question/694664 Status: Answered => Solved Leonard confirmed that the question is solved: Hi Jan, Thanks for your reply. Besides the way you suggest, I also tried using O.dt=(small value)*PWaveTimeStep[5] to decrease the timeStep, as it is computed from sphere radii, rigidities and masses[5]. I hope this way could also solve this problem. Cheers Leonard [5]https://yade- dev.gitlab.io/trunk/yade.utils.html?highlight=pwavetimestep#yade._utils.PWaveTimeStep -- 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 #694664]: Tiny particles don't react with the wall
Question #694664 on Yade changed: https://answers.launchpad.net/yade/+question/694664 Status: Open => Answered Jan Stránský proposed the following answer: Hello, > I use this model for triaxial compression test > the example figure could be find at [1] please provide the code [2] > I guessed it is that there was no contact detection between these tiny particles and the top wall so that these particles passed through the top wall. it is the most reasonable explanation > And I use GlobalStiffnessTimeStepper > Then I set the timestepSafetyCoefficient GlobalStiffnessTimeStepper, as the name suggest, set time step according to stiffness, not particle sizes/velocities > (1) The higher the timestepSafetyCoefficient, the more safe the dt is? Or the lower the timestepSafetyCoefficient, the more safe the dt is? GlobalStiffnessTimeStepper computes something, which is then multiplied by GlobalStiffnessTimeStepper to get actual dt [3]. So the lower value, the more safety. But again, safety w.r.t. stiffness, not particle sizes/velocities. So for this problem, go another way than timestepSafetyCoefficient > (2) Is there any other way to let the missed contacts being detected correctly during the simulation? of course. For example you can: - set maximum wall velocity - compute respective time step such that the maximum wall displacement during one time step is some fraction of tiny particles size - set this time step as maxDt [4]. cheers Jan [2] https://www.yade-dem.org/wiki/Howtoask [3] https://gitlab.com/yade-dev/trunk/-/blob/master/pkg/dem/GlobalStiffnessTimeStepper.cpp, search timestepSafetyCoefficient [4] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.GlobalStiffnessTimeStepper.maxDt -- 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 #694664]: Tiny particles don't react with the wall
New question #694664 on Yade: https://answers.launchpad.net/yade/+question/694664 Hi, I have a sand model with extral tiny particles among the pore space of the sample, and I use this model for triaxial compression test. The boundary condition is simulated by six rigid walls (use walls=aabbWalls([mn,mx],thickness=0,material='FrictMat')). And I use GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8) for setting the dt. However, I found that at the end of the simulation (where axial strain = 40%), many tiny particles stay at their original places, which means that these tiny particles didn't react with the boundary wall during the simulation, the example figure could be find at [1]. I guessed it is that there was no contact detection between these tiny particles and the top wall so that these particles passed through the top wall. Then I set the timestepSafetyCoefficient from 0.8 to 0.1 to decrease the dt (not sure if it is correct), but I gained the same result as [1] shows. My questions are: (1) The higher the timestepSafetyCoefficient, the more safe the dt is? Or the lower the timestepSafetyCoefficient, the more safe the dt is? (2) Is there any other way to let the missed contacts being detected correctly during the simulation? Thanks very much! Leonard [1]https://we.tl/t-SRQDF5JLh8 -- 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
