Question #660590 on Yade changed: https://answers.launchpad.net/yade/+question/660590
amir gave more information on the question: I have prepared a simple example to clarify the problem. https://drive.google.com/open?id=1Vkl5lb89BXlxzaj44N3kPDMfy_a8cQDr In the first script (tst1.py), one sphere was created on the facet and gravity force was applied on the sphere. The simulation was run for 100 iterations. The simulation was saved as tst1.yade. The script of tst1.py : from yade import pack, plot, geom, utils, qt E1 = 1e7 #Young's modulus (Pa) poisson1 = 0.3 # Poison ratio frictionAngle = .5 #Friction angle density1 = 2650 #sphere density kg/m3 densitywater = 1000 #water density g = 9.81 #gravity m/s2 r=.5 #radius of sphere (m) O.materials.append(FrictMat(young=E1,poisson=poisson1,frictionAngle=frictionAngle,density=density1, label='mat_spheres')) O.bodies.append(utils.sphere([1,1,.5],r,color=[1,0,0], material='mat_spheres')) O.bodies.append(utils.geom.facetBox((1,1,1),(1,1,1),wallMask=31)) O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb(),Bo1_Wall_Aabb()]), InteractionLoop( [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=0.7), PyRunner(command='func1()',iterPeriod=1,label='checker'), PyRunner(command='func2()',iterPeriod=100) ] O.dt=utils.PWaveTimeStep() O.trackEnergy=True O.resetTime() w=(4.0/3.0*3.1416*r**3)*density1*g # weight of sphere print 'w :', w bodies2 = [b for b in O.bodies if isinstance(b.shape,Sphere) and b.shape.radius == r] print 'number of particles2 :', len(bodies2) for b in bodies2: print 'b.id 1:', b.id print 'positions :', b.state.pos[2] def func1(): i=0 for b in bodies2: print 'iter :', O.iter print 'positions :', b.state.pos[2] print 'velocity :', b.state.vel[2] force=O.forces.f(b.id) print 'force :', force i=i+1 for i in O.interactions: if not i.isReal: continue fn = i.phys.normalForce print 'normalForce :', fn def func2(): O.pause() O.save("tst1.yade") The results for the first and last iteration are as follow: Yade [1]: iter : 1 positions : 0.499452315993 velocity : -0.0433336376693 force : Vector3(0,0,2599.6499999999164) normalForce : Vector3(0,0,1299.8249999999582) normalForce : Vector3(0,0,1299.8249999999582) iter : 2 positions : 0.499009231927 velocity : -0.0544368756667 force : Vector3(0,0,7302.453422629214) normalForce : Vector3(0,0,3651.226711314607) normalForce : Vector3(0,0,3651.226711314607) iter : 3 positions : 0.498560396874 velocity : -0.0551434362456 force : Vector3(0,0,13210.240974566765) normalForce : Vector3(0,0,6605.120487283382) normalForce : Vector3(0,0,6605.120487283382) . . . iter : 100 positions : 0.498979119867 velocity : -1.60095920204e-10 force : Vector3(0,0,13611.735089527067) normalForce : Vector3(0,0,6805.867544763533) normalForce : Vector3(0,0,6805.867544763533) The second script (tst2.py) load tst1.yade. Then, the sphere was removed and reintroduced. The gravity force was applied on the sphere. The simulation is done for 2 iterations. The tst2.py script: import re from yade import pack, plot,ymport,export,geom,bodiesHandling,qt, utils O.load('test.yade') E1 = 1e7 #Young's modulus (Pa) poisson1 = 0.3 # Poison ratio frictionAngle = .5 #Friction angle density1 = 0 #sphere density kg/m3 density2 = 2650 densitywater = 1000 #water density g = 9.81 #gravity m/s2 r=.5 #radius of sphere (m) sp=SpherePack(); sp.fromSimulation() for b in O.bodies: if isinstance (b.shape,Sphere): O.bodies.erase(b.id) O.bodies.clear() sp.toSimulation() O.bodies.append(utils.geom.facetBox((1,1,1),(1,1,1),wallMask=31)) O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb(),Bo1_Wall_Aabb()]), InteractionLoop( [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=.7), PyRunner(command='func1()',iterPeriod=1,label='checker'), PyRunner(command='func2()',iterPeriod=2) ] O.dt=utils.PWaveTimeStep() O.trackEnergy=True O.resetTime() w=(4.0/3.0*3.1416*r**3)*density2*g # weight of sphere print 'w :', w bodies2 = [b for b in O.bodies if isinstance(b.shape,Sphere) and b.shape.radius == r] print 'number of particles :', len(bodies2) for b in bodies2: print 'b.id 1:', b.id print 'positions :', b.state.pos[2] def func1(): i=0 for b in bodies2: print 'iter :', O.iter print 'positions :', b.state.pos[2] print 'velocity :', b.state.vel[2] print 'force :', O.forces.f(b.id) i=i+1 for i in O.interactions: if not i.isReal: continue fn = i.phys.normalForce print 'normalForce :', fn def func2(): O.save("tst2.yade") O.pause() The results: Yade [1]: iter : 1 positions : 0.499489566596 velocity : 0.0387587036878 force : Vector3(0,0,22024.170567462126) ??? normalForce : Vector3(0,0,5506.042641865532) normalForce : Vector3(0,0,5506.042641865532) normalForce : Vector3(0,0,5506.042641865532) normalForce : Vector3(0,0,5506.042641865532) iter : 2 positions : 0.49980502513 velocity : 0.0387569274068 force : Vector3(0,0,13611.55744917723) normalForce : Vector3(0,0,3402.8893622943074) normalForce : Vector3(0,0,3402.8893622943074) normalForce : Vector3(0,0,3402.8893622943074) normalForce : Vector3(0,0,3402.8893622943074) My questions: Why body force (Vector3(0,0,22024.170567462126) ) on the sphere in the 1st iteration is equal to 22024.170567462126 while it has to be equal to 13611.73. I have also applied the velocity of sphere from the loaded file before the 1st iteration, but it does not change anything. I was wondering if you could help me to solve the problem. Thanks a lot -- 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
