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- # e1=0.618
- # confinement stress / contrainte de confinement = 100000 Pa
- # ammount of particles: 1000
- from yade import pack
- # to create a table to use later
- nRead=utils.readParamsFromTable(
- num_spheres=1000,# number of spheres (choose little to have faster result)
- compFricDegree = 0, # contact friction during the confining phase, to avoid the "effet de voute"
- unknownOk=True
- )
- from yade.params import table # import the table to the data
- num_spheres=table.num_spheres # number of spheres
- targetPorosity = 0.382 #the porosity we want for the packing [indice des vides e=0.618, n=e/(e+1)]
- 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=0.001 # loading rate (strain rate) initial value=0.02
- damp=0.2 # damping coefficient (initial value=0.2)
- stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
- key='_triax_base_' # put you simulation's name here
- young=356e6 # contact stiffness kn/Ds
- mn,mx=Vector3(-0.1,-0.1,-0.1),Vector3(0.1,0.1,0.1) # corners of the initial packing // page 87 Luc Sibille
- thick = 0.01 # thickness of the plates (chose whatever)
- # create materials for spheres and plates
- # in this one poisson=k_t/k_n=042
- 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'))
- # the explanation of this definition is at the page 298 in the YADE.pdf
- # young and poisson are not always modulus of elasticity and possion coefficient, it depends on the IPhys (look in pdf)
- # create walls around the packing
- walls=utils.aabbWalls([mn,mx],thickness=thick,material='walls') # one always includes the pair of vectors of dimension, mat and epaisseur
- wallIds=O.bodies.append(walls) # add it into modelisation
- # use a SpherePack object to generate a random loose particles packing
- sp=pack.SpherePack()
- #psdSizes=[0.002,0.003,0.004,0.005,0.006,0.007,0.008,0.0092]
- #psdCumm=[0.01,0.09,0.25,0.5,0.69,0.9,0.95,1]
- psdSizes=[0.002,0.003,0.004,0.005,0.006,0.007,0.008,0.0092]
- psdCumm=[1,9,25,50,69,90,95,100]
- # sp.makeCloud(mn,mx,0.00575,0.065,num_spheres,False,porosity=0.3819,psdSizes=[0.002,0.003,0.004,0.005,0.006,0.007,0.008,0.0092],psdCumm=[0.01,0.09,0.25,0.5,0.69,0.9,0.95,1],False) # psd method
- # if that not works, try the answered question in YADE launchpad
- sp.particleSD(mn,mx,0.00575,True,'GiaHien',num_spheres,psdSizes,psdCumm,False,0)
- O.bodies.append([utils.sphere(center,rad,material='spheres') for center,rad in sp])
- ############################
- ### DEFINING ENGINES ###
- ############################
- triax=ThreeDTriaxialEngine(
- maxMultiplier=1.01, # spheres growing factor (fast growth)
- finalMaxMultiplier=1.001, # spheres growing factor (slow growth)
- thickness = thick,
- stressControl_1 = True, #switch stress/strain control
- stressControl_2 = False, # on the axis 2 we will use imposed displacement method
- stressControl_3 = True, # essayer a garder la contrainte de confinement
- ## The stress used for (isotropic) internal compaction
- sigma_iso = 100000,
- ## Independant stress values for anisotropic loadings
- internalCompaction=True, # 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
- wallDamping=0.8,
- )
- #comp=TriaxialStressController(
- # sigma1=100000,
- # sigma3=100000,
- #)
- 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()]
- ),
- GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
- triax,
- TriaxialStateRecorder(iterPeriod=100,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()
- #######################################
- ### 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
- if unb<stabilityThreshold and abs(meanS-triax.sigma_iso)/triax.sigma_iso<0.001:
- break
- O.save('confinedState'+key+'.yade.gz')
- print "### Isotropic state saved ###"
- print "current porosity",triax.porosity
- ###################################################
- ### REACHING A SPECIFIED POROSITY PRECISELY ###
- ###################################################
- 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 ###"
- ##############################
- ### DEVIATORIC LOADING ###
- ##############################
- ##We move to deviatoric loading, let us turn internal compaction off to keep particles sizes constant
- triax.internalCompaction=False
- triax.isAxisymetric=True
- ## Change contact friction (remember that decreasing it would generate instantaneous instabilities)
- triax.setContactProperties(finalFricDegree)
- ## We turn all these flags true, else boundaries will be fixed
- triax.wall_bottom_activated=False #fix the bottom plate
- triax.wall_top_activated=True
- triax.wall_left_activated=True
- triax.wall_right_activated=True
- triax.wall_back_activated=True
- triax.wall_front_activated=True
- ##If we want a triaxial loading at imposed strain rate, let's assign srain rate instead of stress
- triax.stressControl_2=0 # for boolean variety, 1 means True and 0 means False
- triax.strainRate2=rate
- triax.sigma1=100000,
- triax.sigma2=0,
- triax.sigma3=100000,
- #wall_left_id=0 # coordinate 0-
- #wall_right_id=1 # coordinate 0+
- #wall_bottom_id=2 # coordinate 1-
- #wall_top_id=3 # coordinate 1+
- #wall_back_id=4 # id of boundary, coordinate 2+
- #wall_front_id=5 # coordinate 2+
- ##Save temporary state in live memory. This state will be reloaded from the interface with the "reload" button.
- O.saveTmp()
- #####################################################
- ### 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],
- q=abs(triax.stress(triax.wall_top_id)[1]-triax.stress(triax.wall_front_id)[2]),
- 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':('s11','s22','s33',None,'ev')}
- plot.plots={'e22':'q'}
- plot.saveGnuplot('04_withsave'+key) # awesome, save data and plot script at the same time
- ## display on the screen (doesn't work on VMware image it seems)
- plot.plot()
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