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- # -*- coding: utf-8 -*-
- # Copyright (C) 2010 by Bruno Chareyre *
- # bruno.chareyre_at_grenoble-inp.fr *
- from yade import pack
- ############################################
- ### DEFINING VARIABLES AND MATERIALS ###
- ############################################
- # Batch execution
- nRead=utils.readParamsFromTable(
- num_spheres=10000,# number of spheres
- compFricDegree = 5, # contact friction during the confining phase
- unknownOk=True,
- isoForce=100000
- )
- from yade.params import table
- num_spheres=table.num_spheres# number of spheres
- targetPorosity = 0.382 #the porosity we want for the packing
- compFricDegree = table.compFricDegree # initial contact friction during the confining phase (will be decreased during the REFD compaction process)
- finalFricDegree = 35 # contact friction during the deviatoric loading
- rate=0.002 # loading rate (strain rate)
- damp=0.2 # damping coefficient
- stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
- key='_triax_draine_e618_100_psd' # put you simulation's name here
- young=2006060 # contact stiffness
- mn,mx=Vector3(-0.15,-0.15,-0.15),Vector3(0.15,0.15,0.15) # corners of the initial packing
- thick = 0.01 # thickness of the plates
- ## create materials for spheres and plates
- O.materials.append(FrictMat(young=young,poisson=0.42,frictionAngle=radians(compFricDegree),density=3000,label='spheres'))
- O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=0,density=0,label='walls'))
- ## create walls around the packing
- walls=utils.aabbWalls([mn,mx],thickness=thick,oversizeFactor=1.5,material='walls')
- wallIds=O.bodies.append(walls)
- ## use a SpherePack object to generate a random loose particles packing
- sp=pack.SpherePack()
- psdSizes=[0.002,0.003,0.004,0.005,0.006,0.007,0.008,0.0095] # (sizes or radii of the grains vary from 2mm to 9.5mm)
- psdCumm=[1,9,25,50,69,90,95,100] # the correspondent amount (percentage) of each diameter
- #psdCumm=[0.01,0.09,0.25,0.50,0.69,0.90,0.95,1.00] # for the code do not use percentage
- #---------------------------------------------
- #psdSizes=[0.002,0.004,0.008,0.0095] # (sizes or radii of the grains vary from 2mm to 9.5mm)
- #psdCumm=[1,25,95,100] # the correspondent amount (percentage) of each diameter
- #clumps=False #turn this true for the same example with clumps
- #if clumps:
- # ## approximate mean rad of the futur dense packing for latter use
- # volume = (mx[0]-mn[0])*(mx[1]-mn[1])*(mx[2]-mn[2])
- # mean_rad = pow(0.09*volume/num_spheres,0.3333)
- # ## define a unique clump type (we could have many, see clumpCloud documentation)
- # c1=pack.SpherePack([((-0.2*mean_rad,0,0),0.5*mean_rad),((0.2*mean_rad,0,0),0.5*mean_rad)])
- # ## generate positions and input them in the simulation
- # sp.makeClumpCloud(mn,mx,[c1],periodic=False)
- # sp.toSimulation(material='spheres')
- #else:
- ###################################################
- #method 01
- #sp.makeCloud(mn,mx,-1,0,num_spheres,False, 0.95,psdSizes,psdCumm,False,seed=1) #"seed" make the "random" generation always the same
- #method 02
- sp.particleSD(mn,mx,0.00575,False,'triaxial_test',10000,psdSizes,psdCumm,False,seed=1)
- #method 03
- #sp.particleSD2(psdSizes,psdCumm,10000,False,cloudPorosity=0.95,0)
- # O.bodies.append([utils.sphere(center,rad,material='spheres') for center,rad in sp])
- #or alternatively (higher level function doing exactly the same):
- sp.toSimulation(material='spheres')
- ############################
- ### DEFINING ENGINES ###
- ############################
- triax=TriaxialStressController(
- maxMultiplier=1.001, # spheres growing factor (fast growth)
- finalMaxMultiplier=1.01, # spheres growing factor (slow growth)
- thickness = thick,
- ## switch stress/strain control using a bitmask. What is a bitmask, huh?!
- ## Say x=1 if stress is controlled on x, else x=0. Same for for y and z, which are 1 or 0.
- ## Then an integer uniquely defining the combination of all these tests is: mask = x*1 + y*2 + z*4
- ## to put it differently, the mask is the integer whose binary representation is xyz, i.e.
- ## "100" (1) means "x", "110" (3) means "x and y", "111" (7) means "x and y and z", etc.
- stressMask = 7,
- #the value of confining stress for the intitial (growth) phase
- goal1=table.isoForce,
- goal2=table.isoForce,
- goal3=table.isoForce,
- max_vel=0.005,
- internalCompaction=False, # If true the confining pressure is generated by growing particles
- # Key=key # passed to the engine so that the output file will have the correct name
- )
- newton=NewtonIntegrator(damping=damp)
- O.engines=[
- ForceResetter(),
- InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
- InteractionLoop(
- [Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
- [Ip2_FrictMat_FrictMat_FrictPhys()],
- [Law2_ScGeom_FrictPhys_CundallStrack()]
- ),
- ## We will use the global stiffness of each body to determine an optimal timestep (see https://yade-dem.org/w/images/1/1b/Chareyre&Villard2005_licensed.pdf)
- GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=50,timestepSafetyCoefficient=0.8),
- triax,
- TriaxialStateRecorder(iterPeriod=50,file='WallStresses'+key),
- newton
- ]
- #Display spheres with 2 colors for seeing rotations better
- Gl1_Sphere.stripes=0
- if nRead==0: yade.qt.Controller(), yade.qt.View()
- ## UNCOMMENT THE FOLLOWING SECTIONS ONE BY ONE
- ## DEPENDING ON YOUR EDITOR, IT COULD BE DONE
- ## BY SELECTING THE CODE BLOCKS BETWEEN THE SUBTITLES
- ## AND PRESSING CTRL+SHIFT+D
- #######################################
- ### APPLYING CONFINING PRESSURE ###
- #######################################
- while 1:
- O.run(1000, True)
- #the global unbalanced force on dynamic bodies, thus excluding boundaries, which are not at equilibrium
- unb=unbalancedForce()
- #average stress
- #note: triax.stress(k) returns a stress vector, so we need to keep only the normal component
- meanS=(triax.stress(triax.wall_right_id)[0]+triax.stress(triax.wall_top_id)[1]+triax.stress(triax.wall_front_id)[2])/3
- print 'unbalanced force:',unb,' mean stress: ',meanS, 'void ratio=', triax.porosity/(1-triax.porosity)
- if unb<stabilityThreshold and abs(meanS-table.isoForce)/table.isoForce<0.001:
- break
- O.save('confinedState'+key+'.yade.gz')
- print "### Isotropic state saved ###"
- print 'current porosity=',triax.porosity
- print 'current void ratio=',triax.porosity/(1-triax.porosity)
- ###################################################
- ### REACHING A SPECIFIED POROSITY PRECISELY ###
- ###################################################
- ### We will reach a prescribed value of porosity with the REFD algorithm
- ### (see http://dx.doi.org/10.2516/ogst/2012032 and
- ### http://www.geosyntheticssociety.org/Resources/Archive/GI/src/V9I2/GI-V9-N2-Paper1.pdf)
- import sys #this is only for the flush() below
- while triax.porosity>targetPorosity:
- # we decrease friction value and apply it to all the bodies and contacts
- compFricDegree = 0.95*compFricDegree
- setContactFriction(radians(compFricDegree))
- print "\r Friction: ",compFricDegree," porosity:",triax.porosity,
- sys.stdout.flush()
- # while we run steps, triax will tend to grow particles as the packing
- # keeps shrinking as a consequence of decreasing friction. Consequently
- # porosity will decrease
- O.run(500,1)
- O.save('compactedState'+key+'.yade.gz')
- print "### Compacted state saved ###"
- print 'current porosity=',triax.porosity
- print 'current void ratio=',triax.porosity/(1-triax.porosity)
- ##############################
- ### DEVIATORIC LOADING ###
- ##############################
- triax.goal1=triaxgoal2=triax.goal3=100000
- #We move to deviatoric loading, let us turn internal compaction off to keep particles sizes constant
- #triax.internalCompaction=False
- # Change contact friction (remember that decreasing it would generate instantaneous instabilities)
- #setContactFriction(radians(finalFricDegree))
- setContactFriction(radians(35))
- #set stress control on x and z, we will impose strain rate on y (5)
- triax.stressMask = 5
- #now goal2 is the target strain rate
- triax.goal2=-rate
- #we assign constant stress to the other directions
- triax.goal1=100000
- triax.goal3=100000
- ##we can change damping here. What is the effect in your opinion?
- newton.damping=0.1
- ##Save temporary state in live memory. This state will be reloaded from the interface with the "reload" button.
- O.saveTmp()
- #####################################################
- ### Example of how to record and plot data ###
- #####################################################
- from yade import plot
- ## a function saving variables
- def history():
- plot.addData(e11=triax.strain[0], e22=triax.strain[1], e33=triax.strain[2],
- ev=-triax.strain[0]-triax.strain[1]-triax.strain[2],
- s11=triax.stress(triax.wall_right_id)[0],
- s22=triax.stress(triax.wall_top_id)[1],
- s33=triax.stress(triax.wall_front_id)[2],
- p=(triax.stress(triax.wall_right_id)[0]+triax.stress(triax.wall_top_id)[1]+triax.stress(triax.wall_front_id)[2])/3000,
- q=(triax.stress(triax.wall_top_id)[1]-triax.stress(triax.wall_front_id)[2])/1000,
- i=O.iter)
- if 1:
- # include a periodic engine calling that function in the simulation loop
- O.engines=O.engines[0:5]+[PyRunner(iterPeriod=20,command='history()',label='recorder')]+O.engines[5:7]
- O.engines.insert(4,PyRunner(iterPeriod=20,command='history()',label='recorder'))
- else:
- # With the line above, we are recording some variables twice. We could in fact replace the previous
- # TriaxialRecorder
- # by our periodic engine. Uncomment the following line:
- O.engines[4]=PyRunner(iterPeriod=20,command='history()',label='recorder')
- O.run(100,True)
- ### declare what is to plot. "None" is for separating y and y2 axis
- #plot.plots={'i':('e11','e22','e33',None,'s11','s22','s33')}
- ### the traditional triaxial curves would be more like this:
- plot.plots={'e22':('q')}
- ## display on the screen (doesn't work on VMware image it seems)
- plot.plot()
- ##### PLAY THE SIMULATION HERE WITH "PLAY" BUTTON OR WITH THE COMMAND O.run(N) #####
- ## In that case we can still save the data to a text file at the the end of the simulation, with:
- plot.saveDataTxt('results'+key)
- ##or even generate a script for gnuplot. Open another terminal and type "gnuplot plotScriptKEY.gnuplot:
- plot.saveGnuplot('plotScript'+key)
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