# 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 unbtargetPorosity: ## 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()