Question #676841 on Yade changed: https://answers.launchpad.net/yade/+question/676841
fengjingyu posted a new comment: Hi Jan, Thank you for spending so much time with me. I don't know how to repay you.Thank you again. You said Yade (DEM in general) considers particles as perfectly rigid. But when I run the following Oedometric test script(from https://yade- dem.org/doc/tutorial-examples.html).I found that the wall would be compressed into the upper ball, and in addition, the ball would overlap with the ball.So i think it is soft ball model.I may have a problem with my understanding. Please point out my mistake. Thank you. Feng #################################### # gravity deposition, continuing with oedometric test after stabilization # shows also how to run parametric studies with yade-batch # The components of the batch are: # 1. table with parameters, one set of parameters per line (ccc.table) # 2. readParamsFromTable which reads respective line from the parameter file # 3. the simulation muse be run using yade-batch, not yade # # $ yade-batch --job-threads=1 03-oedometric-test.table 03-oedometric-test.py # # load parameters from file if run in batch # default values are used if not run from batch readParamsFromTable(rMean=.05,rRelFuzz=.3,maxLoad=1e6,minLoad=1e4) # make rMean, rRelFuzz, maxLoad accessible directly as variables later from yade.params.table import * # create box with free top, and ceate loose packing inside the box from yade import pack, plot O.bodies.append(geom.facetBox((.5,.5,.5),(.5,.5,.5),wallMask=31)) sp=pack.SpherePack() sp.makeCloud((0,0,0),(1,1,1),rMean=rMean,rRelFuzz=rRelFuzz) sp.toSimulation() O.engines=[ ForceResetter(), # sphere, facet, wall InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb(),Bo1_Wall_Aabb()]), InteractionLoop( # the loading plate is a wall, we need to handle sphere+sphere, sphere+facet, sphere+wall [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom(),Ig2_Wall_Sphere_ScGeom()], [Ip2_FrictMat_FrictMat_FrictPhys()], [Law2_ScGeom_FrictPhys_CundallStrack()] ), NewtonIntegrator(gravity=(0,0,-9.81),damping=0.5), # the label creates an automatic variable referring to this engine # we use it below to change its attributes from the functions called PyRunner(command='checkUnbalanced()',realPeriod=2,label='checker'), ] O.dt=.5*PWaveTimeStep() # the following checkUnbalanced, unloadPlate and stopUnloading functions are all called by the 'checker' # (the last engine) one after another; this sequence defines progression of different stages of the # simulation, as each of the functions, when the condition is satisfied, updates 'checker' to call # the next function when it is run from within the simulation next time # check whether the gravity deposition has already finished # if so, add wall on the top of the packing and start the oedometric test def checkUnbalanced(): # at the very start, unbalanced force can be low as there is only few contacts, but it does not mean the packing is stable if O.iter<5000: return # the rest will be run only if unbalanced is < .1 (stabilized packing) if unbalancedForce()>.1: return # add plate at the position on the top of the packing # the maximum finds the z-coordinate of the top of the topmost particle O.bodies.append(wall(max([b.state.pos[2]+b.shape.radius for b in O.bodies if isinstance(b.shape,Sphere)]),axis=2,sense=-1)) global plate # without this line, the plate variable would only exist inside this function plate=O.bodies[-1] # the last particles is the plate # Wall objects are "fixed" by default, i.e. not subject to forces # prescribing a velocity will therefore make it move at constant velocity (downwards) plate.state.vel=(0,0,-.1) # start plotting the data now, it was not interesting before O.engines=O.engines+[PyRunner(command='addPlotData()',iterPeriod=200)] # next time, do not call this function anymore, but the next one (unloadPlate) instead checker.command='unloadPlate()' def unloadPlate(): # if the force on plate exceeds maximum load, start unloading if abs(O.forces.f(plate.id)[2])>maxLoad: plate.state.vel*=-1 # next time, do not call this function anymore, but the next one (stopUnloading) instead checker.command='stopUnloading()' def stopUnloading(): if abs(O.forces.f(plate.id)[2])<minLoad: # O.tags can be used to retrieve unique identifiers of the simulation # if running in batch, subsequent simulation would overwrite each other's output files otherwise # d (or description) is simulation description (composed of parameter values) # while the id is composed of time and process number plot.saveDataTxt(O.tags['d.id']+'.txt') O.pause() def addPlotData(): if not isinstance(O.bodies[-1].shape,Wall): plot.addData(); return Fz=O.forces.f(plate.id)[2] plot.addData(Fz=Fz,w=plate.state.pos[2]-plate.state.refPos[2],unbalanced=unbalancedForce(),i=O.iter) # besides unbalanced force evolution, also plot the displacement-force diagram plot.plots={'i':('unbalanced',),'w':('Fz',)} plot.plot() O.run() # when running with yade-batch, the script must not finish until the simulation is done fully # this command will wait for that (has no influence in the non-batch mode) waitIfBatch() ############################## -- 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 : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
