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  1. # -*- coding: utf-8 -*-
  2.  
  3. #  Copyright (C) 2010 by Bruno Chareyre                                  *
  4. #  bruno.chareyre_at_grenoble-inp.fr                                     *
  5.  
  6. from yade import pack
  7.  
  8. ############################################
  9. ###   DEFINING VARIABLES AND MATERIALS   ###
  10. ############################################
  11.  
  12. # Batch execution
  13. nRead=utils.readParamsFromTable(
  14.     num_spheres=10000,# number of spheres
  15.     compFricDegree = 5, # contact friction during the confining phase
  16.     unknownOk=True,
  17.     isoForce=100000
  18. )
  19. from yade.params import table
  20.  
  21. num_spheres=table.num_spheres# number of spheres
  22. targetPorosity = 0.382 #the porosity we want for the packing
  23. compFricDegree = table.compFricDegree # initial contact friction during the confining phase (will be decreased during the REFD compaction process)
  24. finalFricDegree = 35 # contact friction during the deviatoric loading
  25. rate=0.002 # loading rate (strain rate)
  26. damp=0.2 # damping coefficient
  27. stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
  28. key='_triax_draine_e618_100_psd' # put you simulation's name here
  29. young=2006060 # contact stiffness
  30. mn,mx=Vector3(-0.15,-0.15,-0.15),Vector3(0.15,0.15,0.15) # corners of the initial packing
  31. thick = 0.01 # thickness of the plates
  32.  
  33.  
  34. ## create materials for spheres and plates
  35. O.materials.append(FrictMat(young=young,poisson=0.42,frictionAngle=radians(compFricDegree),density=3000,label='spheres'))
  36. O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=0,density=0,label='walls'))
  37.  
  38. ## create walls around the packing
  39. walls=utils.aabbWalls([mn,mx],thickness=thick,oversizeFactor=1.5,material='walls')
  40. wallIds=O.bodies.append(walls)
  41.  
  42. ## use a SpherePack object to generate a random loose particles packing
  43. sp=pack.SpherePack()
  44. 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)
  45. psdCumm=[1,9,25,50,69,90,95,100] # the correspondent amount (percentage) of each diameter
  46. #psdCumm=[0.01,0.09,0.25,0.50,0.69,0.90,0.95,1.00] # for the code do not use percentage
  47. #---------------------------------------------
  48. #psdSizes=[0.002,0.004,0.008,0.0095] # (sizes or radii of the grains vary from 2mm to 9.5mm)
  49. #psdCumm=[1,25,95,100] # the correspondent amount (percentage) of each diameter
  50.  
  51. #clumps=False #turn this true for the same example with clumps
  52. #if clumps:
  53. # ## approximate mean rad of the futur dense packing for latter use
  54. # volume = (mx[0]-mn[0])*(mx[1]-mn[1])*(mx[2]-mn[2])
  55. # mean_rad = pow(0.09*volume/num_spheres,0.3333)
  56. # ## define a unique clump type (we could have many, see clumpCloud documentation)
  57. # c1=pack.SpherePack([((-0.2*mean_rad,0,0),0.5*mean_rad),((0.2*mean_rad,0,0),0.5*mean_rad)])
  58. # ## generate positions and input them in the simulation
  59. # sp.makeClumpCloud(mn,mx,[c1],periodic=False)
  60. # sp.toSimulation(material='spheres')
  61. #else:
  62.  
  63. ###################################################
  64. #method 01
  65. #sp.makeCloud(mn,mx,-1,0,num_spheres,False, 0.95,psdSizes,psdCumm,False,seed=1) #"seed" make the "random" generation always the same
  66.  
  67. #method 02
  68. sp.particleSD(mn,mx,0.00575,False,'triaxial_test',10000,psdSizes,psdCumm,False,seed=1)
  69. #method 03
  70. #sp.particleSD2(psdSizes,psdCumm,10000,False,cloudPorosity=0.95,0)
  71.  
  72. # O.bodies.append([utils.sphere(center,rad,material='spheres') for center,rad in sp])
  73.  #or alternatively (higher level function doing exactly the same):
  74. sp.toSimulation(material='spheres')
  75.  
  76. ############################
  77. ###   DEFINING ENGINES   ###
  78. ############################
  79.  
  80. triax=TriaxialStressController(
  81.     maxMultiplier=1.001, # spheres growing factor (fast growth)
  82.     finalMaxMultiplier=1.01, # spheres growing factor (slow growth)
  83.     thickness = thick,
  84.     ## switch stress/strain control using a bitmask. What is a bitmask, huh?!
  85.     ## Say x=1 if stress is controlled on x, else x=0. Same for for y and z, which are 1 or 0.
  86.     ## Then an integer uniquely defining the combination of all these tests is: mask = x*1 + y*2 + z*4
  87.     ## to put it differently, the mask is the integer whose binary representation is xyz, i.e.
  88.     ## "100" (1) means "x", "110" (3) means "x and y", "111" (7) means "x and y and z", etc.
  89.     stressMask = 7,
  90.     #the value of confining stress for the intitial (growth) phase
  91.     goal1=table.isoForce,
  92.     goal2=table.isoForce,
  93.     goal3=table.isoForce,
  94.     max_vel=0.005,
  95.     internalCompaction=False, # If true the confining pressure is generated by growing particles
  96. #   Key=key # passed to the engine so that the output file will have the correct name
  97. )
  98.  
  99. newton=NewtonIntegrator(damping=damp)
  100.  
  101. O.engines=[
  102.     ForceResetter(),
  103.     InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Box_Aabb()]),
  104.     InteractionLoop(
  105.         [Ig2_Sphere_Sphere_ScGeom(),Ig2_Box_Sphere_ScGeom()],
  106.         [Ip2_FrictMat_FrictMat_FrictPhys()],
  107.         [Law2_ScGeom_FrictPhys_CundallStrack()]
  108.     ),
  109.     ## 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)
  110.     GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=50,timestepSafetyCoefficient=0.8),
  111.     triax,
  112.     TriaxialStateRecorder(iterPeriod=50,file='WallStresses'+key),
  113.     newton
  114. ]
  115.  
  116. #Display spheres with 2 colors for seeing rotations better
  117. Gl1_Sphere.stripes=0
  118. if nRead==0: yade.qt.Controller(), yade.qt.View()
  119.  
  120. ## UNCOMMENT THE FOLLOWING SECTIONS ONE BY ONE
  121. ## DEPENDING ON YOUR EDITOR, IT COULD BE DONE
  122. ## BY SELECTING THE CODE BLOCKS BETWEEN THE SUBTITLES
  123. ## AND PRESSING CTRL+SHIFT+D
  124.  
  125. #######################################
  126. ###   APPLYING CONFINING PRESSURE   ###
  127. #######################################
  128.  
  129. while 1:
  130.   O.run(1000, True)
  131.   #the global unbalanced force on dynamic bodies, thus excluding boundaries, which are not at equilibrium
  132.   unb=unbalancedForce()
  133.   #average stress
  134.   #note: triax.stress(k) returns a stress vector, so we need to keep only the normal component
  135.   meanS=(triax.stress(triax.wall_right_id)[0]+triax.stress(triax.wall_top_id)[1]+triax.stress(triax.wall_front_id)[2])/3
  136.   print 'unbalanced force:',unb,' mean stress: ',meanS, 'void ratio=', triax.porosity/(1-triax.porosity)
  137.   if unb<stabilityThreshold and abs(meanS-table.isoForce)/table.isoForce<0.001:
  138.     break
  139.  
  140. O.save('confinedState'+key+'.yade.gz')
  141. print "###      Isotropic state saved      ###"
  142. print 'current porosity=',triax.porosity
  143. print 'current void ratio=',triax.porosity/(1-triax.porosity)
  144.  
  145. ###################################################
  146. ###   REACHING A SPECIFIED POROSITY PRECISELY   ###
  147. ###################################################
  148.  
  149. ### We will reach a prescribed value of porosity with the REFD algorithm
  150. ### (see http://dx.doi.org/10.2516/ogst/2012032 and
  151. ### http://www.geosyntheticssociety.org/Resources/Archive/GI/src/V9I2/GI-V9-N2-Paper1.pdf)
  152.  
  153. import sys #this is only for the flush() below
  154. while triax.porosity>targetPorosity:
  155.     # we decrease friction value and apply it to all the bodies and contacts
  156.     compFricDegree = 0.95*compFricDegree
  157.     setContactFriction(radians(compFricDegree))
  158.     print "\r Friction: ",compFricDegree," porosity:",triax.porosity,
  159.     sys.stdout.flush()
  160.     # while we run steps, triax will tend to grow particles as the packing
  161.     # keeps shrinking as a consequence of decreasing friction. Consequently
  162.     # porosity will decrease
  163.     O.run(500,1)
  164.  
  165. O.save('compactedState'+key+'.yade.gz')
  166. print "###    Compacted state saved      ###"
  167. print 'current porosity=',triax.porosity
  168. print 'current void ratio=',triax.porosity/(1-triax.porosity)
  169.  
  170. ##############################
  171. ###   DEVIATORIC LOADING   ###
  172. ##############################
  173. triax.goal1=triaxgoal2=triax.goal3=100000
  174. #We move to deviatoric loading, let us turn internal compaction off to keep particles sizes constant
  175. #triax.internalCompaction=False
  176.  
  177. # Change contact friction (remember that decreasing it would generate instantaneous instabilities)
  178. #setContactFriction(radians(finalFricDegree))
  179. setContactFriction(radians(35))
  180.  
  181. #set stress control on x and z, we will impose strain rate on y (5)
  182. triax.stressMask = 5
  183. #now goal2 is the target strain rate
  184. triax.goal2=-rate
  185. #we assign constant stress to the other directions
  186. triax.goal1=100000
  187. triax.goal3=100000
  188.  
  189. ##we can change damping here. What is the effect in your opinion?
  190. newton.damping=0.1
  191.  
  192. ##Save temporary state in live memory. This state will be reloaded from the interface with the "reload" button.
  193. O.saveTmp()
  194.  
  195. #####################################################
  196. ###    Example of how to record and plot data     ###
  197. #####################################################
  198.  
  199. from yade import plot
  200.  
  201. ## a function saving variables
  202. def history():
  203.     plot.addData(e11=triax.strain[0], e22=triax.strain[1], e33=triax.strain[2],
  204.             ev=-triax.strain[0]-triax.strain[1]-triax.strain[2],
  205.             s11=triax.stress(triax.wall_right_id)[0],
  206.             s22=triax.stress(triax.wall_top_id)[1],
  207.             s33=triax.stress(triax.wall_front_id)[2],
  208.             p=(triax.stress(triax.wall_right_id)[0]+triax.stress(triax.wall_top_id)[1]+triax.stress(triax.wall_front_id)[2])/3000,
  209.             q=(triax.stress(triax.wall_top_id)[1]-triax.stress(triax.wall_front_id)[2])/1000,
  210.             i=O.iter)
  211.  
  212. if 1:
  213.   # include a periodic engine calling that function in the simulation loop
  214.   O.engines=O.engines[0:5]+[PyRunner(iterPeriod=20,command='history()',label='recorder')]+O.engines[5:7]
  215.   O.engines.insert(4,PyRunner(iterPeriod=20,command='history()',label='recorder'))
  216. else:
  217.   # With the line above, we are recording some variables twice. We could in fact replace the previous
  218.   # TriaxialRecorder
  219.   # by our periodic engine. Uncomment the following line:
  220.   O.engines[4]=PyRunner(iterPeriod=20,command='history()',label='recorder')
  221.  
  222. O.run(100,True)
  223.  
  224. ### declare what is to plot. "None" is for separating y and y2 axis
  225. #plot.plots={'i':('e11','e22','e33',None,'s11','s22','s33')}
  226. ### the traditional triaxial curves would be more like this:
  227. plot.plots={'e22':('q')}
  228.  
  229. ## display on the screen (doesn't work on VMware image it seems)
  230. plot.plot()
  231.  
  232. #####  PLAY THE SIMULATION HERE WITH "PLAY" BUTTON OR WITH THE COMMAND O.run(N)  #####
  233.  
  234. ## In that case we can still save the data to a text file at the the end of the simulation, with:
  235. plot.saveDataTxt('results'+key)
  236. ##or even generate a script for gnuplot. Open another terminal and type  "gnuplot plotScriptKEY.gnuplot:
  237. plot.saveGnuplot('plotScript'+key)
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