Re: [Yade-users] [Question #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Jan Stránský posted a new comment: You may also consider creating a new question aiming to the servo control, as here it might be already too "deep" in the thread. Also, it is a separate problem and as such should have its own question [7] Cheers Jan [7] 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
Re: [Yade-users] [Question #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Open => Answered Jan Stránský proposed the following answer: There is an example [5]. you can play with iterPeriod (try 10 or 1 instead of 1000) and/or other parameters. The referenced source code [4] may be useful, as well as documentation itself [6] and links therein. Cheers Jan [5] https://gitlab.com/yade-dev/trunk/-/blob/master/examples/PIDController.py [6] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.ServoPIDController -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Answered => Open Ruidong LI is still having a problem: Hi, Jan. >yes, it looks pretty similar [4] Could you please provide an example of using ServoPIDController? Because there is no tutorial about how to use it. I am inclined to think that this command's explanation is not easy to understand without an example. Many thanks. Looking forward to your reply. Kyle -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Open => Answered Jan Stránský proposed the following answer: > I am not sure whether the principle of the ServoPIDController is the same as that in PFC yes, it looks pretty similar [4] Cheers Jan [4] https://gitlab.com/yade- dev/trunk/-/blob/master/pkg/common/KinematicEngines.cpp#L201 -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Needs information => Open Ruidong LI gave more information on the question: Hi, Jan. >Have you tried ServoPIDController? I try to use it but can't find any tutorials. In PFC [1], the velocity value of the wall is determined by multiplying a factor by the stress difference (target stress minus current stress). This value is updated regularly. I am not sure whether the principle of the ServoPIDController is the same as that in PFC. Looking forward to your reply. Kyle [1]https://docs.itascacg.com/pfc700/pfc/pfcmodule/doc/manual/wall_manual/wall_commands/cmd_wall_servo.html?highlight=servo#command:wall.servo -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Open => Needs information Jan Stránský requested more information: Have you tried ServoPIDController [1]? If yes, why it did not help? Cheers Jan [1] https://yade- dem.org/doc/yade.wrapper.html#yade.wrapper.ServoPIDController -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Ruidong LI gave more information on the question: Can someone help me with servo-control part? Many thanks. -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Answered => Open Ruidong LI is still having a problem: Hi! Jan Thanks for your reply. >the same, what does "will break" mean? That they do not touch each other? The particles went out of the cylinder and flew all around [1]. [1]https://answers.launchpad.net/yade/+question/404479 Cheers, Kyle -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Bruno Chareyre proposed the following answer: Hi, > "My problem is that I just finished the part about generating flexible membranes using Pfacet and don't know what to do next." I did not read all the details but if you are at this step I suppose "what to do next" is to assign forces to the nodes of the membranes to reflect external pressure. It certainly needs to account for some area and local orientation. I never tried such thing myself so I'm not 100% sure what to expect. It should work but it probably needs to update the external forces after large deformations. Cheers Bruno -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Open => Answered Jan Stránský proposed the following answer: >> The loading is simply such that a constant velocity is prescribed >> (s.state.vel = ...) > But which velocity value should I define to achieve quasi-equilibrium > compression? Define such velocity which and whose effect on the sample satisfy your definition of "quasi-equilibrium compression". > Can you show me the code? [2] > I am sorry for my stupidity. stupidity is not the right word here. "Lack of experience" fits better >Therefore I ask for a MWE and better description of "are destroyed" (anyway >useful even with the code). Actually, what I mean is that when you run the 'triax' py without any change, > the triangle facets will break. the same, what does "will break" mean? That they do not touch each other? > And my current problem is not with the 'triax' py. > My problem is that I just finished the part about generating flexible > membranes using Pfacet and don't know what to do next. I do not use PFacet myself, so I cannot help here.. But thanks for description, maybe you can open a new more specific question (here the description is maybe too "deep" in the thread) Cheers Jan [2] https://gitlab.com/yade- dev/trunk/-/blob/master/examples/concrete/triax.py#L73 -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Needs information => Open Ruidong LI gave more information on the question: Hi! Jan Thanks for your reply. > The loading is simply such that a constant velocity is prescribed > (s.state.vel = ...) But which velocity value should I define to achieve quasi-equilibrium compression? Can you show me the code? I am sorry for my stupidity. >Therefore I ask for a MWE and better description of "are destroyed" (anyway >useful even with the code). Actually, what I mean is that when you run the 'triax' py without any change, the triangle facets will break. And my current problem is not with the 'triax' py. My problem is that I just finished the part about generating flexible membranes using Pfacet and don't know what to do next. What I want to achieve is isotropic compression with a confining pressure equal to 50 kPa. And then, maintain the confining pressure in the x and y directions and apply a displacement-controlled movement of the top wall. my MWE is presented as below ###1 ### ### LOAD INITIAL PACKING ### dir_inipacking = '/home/kyle/Yade/install/bin/lentils/xml/iniPacking.xml' O.load(dir_inipacking) # Define engine O.engines = [ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(), Bo1_PFacet_Aabb(),], sortThenCollide=True), InteractionLoop( [ Ig2_GridNode_GridNode_GridNodeGeom6D(), Ig2_GridConnection_GridConnection_GridCoGridCoGeom(), Ig2_Sphere_Sphere_ScGeom6D(), Ig2_Sphere_PFacet_ScGridCoGeom(), ], [ Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(setCohesionNow=True,setCohesionOnNewContacts=True), Ip2_FrictMat_FrictMat_FrictPhys() ], [ Law2_ScGeom6D_CohFrictPhys_CohesionMoment(), Law2_ScGeom_FrictPhys_CundallStrack(), Law2_ScGridCoGeom_FrictPhys_CundallStrack(), Law2_GridCoGridCoGeom_FrictPhys_CundallStrack(), ] ), GlobalStiffnessTimeStepper(timestepSafetyCoefficient=0.8,label='ts'), NewtonIntegrator(gravity=(0,-9.81,0),damping=0.1,label='newton') ] # encoding: utf-8 from yade import qt from yade.gridpfacet import * import math ### 2 ### ### DEFINING VARIABLES AND MATERIALS ### # The following lines are used parameter definitions readParamsFromTable( # directory dir_vtk = '/home/kyle/Yade/install/bin/lentils/vtk/20', # directory of storing vtk files dir_txt = '/home/kyle/Yade/install/bin/lentils/txt/20/Num20_servo.txt', # directory of storing txt files dir_xml = '/home/kyle/Yade/install/bin/lentils/xml/20', # directory of storing xml files # material parameters young_w = 5e9, # Young's modulus of plates and walls young_g = 1.8e6, # Young's modulus of grains [1] den_w = 7874, # density of plates and walls den_g = 980, # density of grains poi_w = 0.3, # possion's ratio of plates and walls poi_g = 0.25, # possion's ratio of grains friAngle_w = 0.5,#radians(15), # friction angle of plates and walls friAngle_g = 0.5,#radians(29), # friction angle of grains # Parameters of cylindrical walls x_cyl = 0.0547, # x-coordinate of center of cylindrical walls y_cyl = 0.0535, # y-coordinate of center of cylindrical walls z_cyl = 0, # z-coordinate of center of cylindrical walls r_cyl = 0.0358, # radius of the cylinder h_cyl = 0.14, # height of the cylinder # confining pressure preStress = -5, # axial strain rate strainRate=-100 ) from yade.params.table import * ### 3### ### CREATE TOP AND BOTTOM PLATES ### # erase rigid cylindrical facets for b in O.bodies: if isinstance(b.shape,Facet): O.bodies.erase(b.id) # create top and bottom plates h_cyl = max([b.state.pos[2] + b.shape.radius for b in O.bodies if isinstance(b.shape, Sphere)]) top_plate = O.bodies.append(yade.geom.facetCylinder((x_cyl,y_cyl,h_cyl),radius=r_cyl*1.2,height=0,segmentsNumber=40,color=(1,1,1))) bottom_plate = O.bodies.append(yade.geom.facetCylinder((x_cyl,y_cyl,0),radius=r_cyl*1.2,height=0,segmentsNumber=40,color=(1,1,1))) ''' vel = strainRate * (h - rParticle * 2 * bcCoeff) for s in bot: s.shape.color = (1,
Re: [Yade-users] [Question #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Open => Needs information Jan Stránský requested more information: > How do I achieve servo control? I am still not clear about this e.g. using ServoPIDController [1] > I guess there is no displacement-based servo control in the code 'triax.py' Yes. The loading is simply such that a constant velocity is prescribed (s.state.vel = ...) >>> But the problem is that when implementing the code, facets generated using >>> the command 'Pfacet' are destroyed >> what does "are destroyed" mean? please provide a MWE > Maybe you can try to run the code 'triax.py' and you will understand what I > am talking about. No, I will not understand, since there are no PFacets in current triax.py. Therefore I ask for a MWE and better description of "are destroyed" (anyway useful even with the code). 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Answered => Open Ruidong LI is still having a problem: Dear Jan, Thanks for your reply. 1) I'll check. Many thanks. 2) I'll check. Many thanks. 3) How do I achieve servo control? I am still not clear about this. I guess there is no displacement-based servo control in the code 'triax.py'. 4) This means the cylindrical surface is divided into triangles. Maybe you can try to run the code 'triax.py' and you will understand what I am talking about. 5) I'll check. Many thanks. Cheers, Kyle -- 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 #707148]: Cylindrical triaxial test using Pfacet
Question #707148 on Yade changed: https://answers.launchpad.net/yade/+question/707148 Status: Open => Answered Jan Stránský proposed the following answer: Hello, 1) Yes 2) triax.py 3) How do I achieve servo control? 4) [1] - what does "are destroyed" mean? - please provide a MWE 5) triax.py Of course, triax.py is just a primitive approach - a cylindrical surface divided in triangles with fixed force. It will not work if the surface is significantly distorted and it does not contain any "membrane effect". You can use other shapes for the surface, maybe a bit overlapped? Or PFacets to also simulate a membrane effect. Or ... Cheers Jan [1] https://yade- dem.org/doc/yade.wrapper.html#yade.wrapper.ServoPIDController -- 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
