New question #688197 on Yade: https://answers.launchpad.net/yade/+question/688197
I made a simple model to understand what’s going on. I have two spheres: sphere(center=(0,0,0),radius=0.5,fixed=True,material='mat1'), sphere((0,0,1),radius=0.5,material='mat1'), The following is the boundary condition: O.bodies[1].state.blockedDOFs = "xyzXYZ" O.bodies[1].state.vel = (0.0001,0,0) O.bodies[1].state.angVel = (0,0,0) I am applying a velocity in the x direction on sphere #1 which should cause a shear reaction force to occur. The following are my questions: 1. When I track the forces on sphere #1, I notice that there is a force in the x-direction (which is expected) and a force in the z-direction (uniaxial). Where is the uniaxial force coming from if I only applied a shear boundary condition? The contrary example to this would be to apply a uniaxial loading condition which would result in only a uniaxial force. 2. I have read [1] and [2] thoroughly. I understand that the tangential plane rotates as the spheres shear and that the shear force is calculated incrementally. Is deltaUs in [2] the change in tangential displacement with respect to time or is it from the initial configuration? 3. I tried to do a simple DEM model on MATLAB where I had two 2D spheres and I applied the same loading condition as my YADE model while calculating the uniaxial and shear forces on sphere#1. I could not get the same results as YADE predicts. Is there a document that explains clearly the steps. I read [1], but I want something with more detail. 4. My code is running well, so I assume that the my code is correct. [1] https://yade-dem.org/doc/formulation.html#fig-shear-2d [2] A DEM model for soft and hard rocks: Role of grain interlocking on strength Thank you soo much for your time. MY CODE: # MATERIAL PROPERTIES intR=20 # allows near neighbour interaction (can be adjusted for every packing) DENS=2500 # Density YOUNG=1800 FRICT=7 ALPHA=0.1 TENS=100 COH=100 iterMax = 100 O.materials.append(JCFpmMat(type=1,density=DENS,young=YOUNG,poisson=ALPHA,frictionAngle=radians(FRICT),tensileStrength=TENS,cohesion=COH,label='mat1')) # PARTICLES O.bodies.append([ # 0 sphere(center=(0,0,0),radius=0.5,fixed=True,material='mat1'), # 1 sphere((0,0,1),radius=0.5,material='mat1') ]) nbSpheres = 2; # BOUNDARY CONDITION O.bodies[1].state.blockedDOFs = "xyzXYZ" O.bodies[1].state.vel = (0.0001,0,0) O.bodies[1].state.angVel = (0,0,0) # FUNCTIONAL COMPONENTS # 1 def addPlotData1(): plot.addData(t=O.time,DX1 = O.bodies[1].state.pos[0],DY1 = O.bodies[1].state.pos[1],DZ1 = O.bodies[1].state.pos[2], FX1 = O.forces.f(1)[0], FY1 = O.forces.f(1)[1], FZ1 = O.forces.f(1)[2]) # 2 def addPlotData2(): plot.saveDataTxt('/home/nabid/Desktop/SCRIPTS/dataFile.txt',vars=('t','DX1','DY1','DZ1','FX1','FY1','FZ1')) #PRINTING from yade import plot from pprint import pprint # SIMULATION LOOP O.engines=[ PyRunner(command='addPlotData1()',iterPeriod=1), PyRunner(command='addPlotData2()',iterPeriod=1), ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb()]), InteractionLoop( [Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=intR)], [Ip2_JCFpmMat_JCFpmMat_JCFpmPhys(cohesiveTresholdIteration=1)], [Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM()] ), GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=10,timestepSafetyCoefficient=0.5, defaultDt=utils.PWaveTimeStep()), NewtonIntegrator(damping=0.1), ] #TIME STEP O.dt=0.5e-4*PWaveTimeStep() #PLOTTING plot.plots={'DX1':('FX1'),'DX1':('FZ1')} plot.plot() # SAVE SIMULATION -- 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
