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[Christian Sommerfeld <question211358@xxxxxxxxxxxxxxxxxxxxx>]

New question #211358 on Yade:
https://answers.launchpad.net/yade/+question/211358

Hi,

i want to validate a simple test with 2 balls. But i get a force in my simulation which is so much higher than the force of the real test. So i take a look in my code for 2 days but i can't find any mistake. 

The experiment: The first ball has the material porcelain and this ball falls down from a high of 0,1 m with the normal gravity 9,81. At the point (0,0,0) is the second ball which has teh material steel and this ball is fixed. In the real experimentr i get for the approach a force of 6 N in the direction of movement. For the simulazion i  use the SI- units for all of my parameters to make it as easy as possible. But i get a force of 350 N and i do know why?


from yade import  plot, geom, utils

O.materials.append(FrictMat(young=210e9,poisson=0.3,frictionAngle=.5,density=7900, label='mat_ground'))

O.materials.append(FrictMat(young=90e9,poisson=0.14,frictionAngle=.5,density=2500, label='mat_spheres'))

O.bodies.append(utils.sphere([0,0,0.103],0.003,color=[1,1,0], material='mat_spheres'))

O.bodies.append(utils.sphere([0,0,0.003],0.003,color=[1,1,1], fixed=True, material='mat_ground'))

O.engines=[
   ForceResetter(),
   InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()]),
   InteractionLoop(
      [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom()],
      [Ip2_FrictMat_FrictMat_FrictPhys()],
      [Law2_ScGeom_FrictPhys_CundallStrack()]

   ),
  NewtonIntegrator(damping=0.2, gravity=(0,0,-9.81)),
 PyRunner(iterPeriod=5,command="myAddPlotData()")
]

O.dt=1*utils.PWaveTimeStep()

def myAddPlotData():
	force=plot.addData(t=O.time,F=O.forces.f(0).norm())

plot.plots={'t':('F')}
plot.plot()

from yade import qt
v=qt.View()

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