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[Zhicheng Gao <question697778@xxxxxxxxxxxxxxxxxxxxx>]

New question #697778 on Yade:
https://answers.launchpad.net/yade/+question/697778

Hi,
I use the FlowEngine and get some problems. I use the pack module to generate particles, when I set the seed=2 or 3, I get such warning:
Failed to triangulate body with id=47 Point=-1976.72 1535.93 -26.6935 rad=0.03
Failed to triangulate body with id=57 Point=1343.75 -3820.83 -831.97 rad=0.03
.........
NEGATIVE DETERMINANT
NEGATIVE DETERMINANT
Thank you for your attention to this matter !
May code is shown as follow:
#=============================================

from yade import pack,qt,plot

num_spheres=1000# number of spheres
young=1e6
compFricDegree = 3 # initial contact friction during the confining phase
finalFricDegree = 30 # contact friction during the deviatoric loading
mn,mx=Vector3(0,0,0),Vector3(2,2,6) # corners of the initial packing
flag=1
flag2=0

O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=radians(compFricDegree),density=2600,label='spheres'))
O.materials.append(FrictMat(young=young,poisson=0.5,frictionAngle=0,density=0,label='walls'))
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)

sp=pack.SpherePack()
sp.makeCloud(mn,mx,rMean=0.3,rRelFuzz=0,num=20,periodic=False,seed=3)
sp.makeCloud(mn,mx,rMean=0.03,rRelFuzz=0,num=1000,periodic=False,seed=3)
sp.toSimulation(material='spheres')

triax=TriaxialStressController(
 thickness = 0,
 stressMask = 7,
 max_vel = 0.005,
 internalCompaction=0, # If true the confining pressure is generated by growing particles
# wall_bottom_activated=False
)

newton=NewtonIntegrator(damping=0.2)

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()],label="iloop"
 ),
 FlowEngine(dead=1,label="flow"),#introduced as a dead engine for the moment, see 2nd section
 GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),
 triax,
 newton,
]

triax.goal1=triax.goal2=triax.goal3=-10000

while 1:
  O.run(1000,1)
  unb=unbalancedForce()
  if unb<0.001 and abs(-10000-triax.meanStress)/10000<0.001:
    break

setContactFriction(radians(finalFricDegree))

## ______________ Oedometer section _________________

triax.stressMask=7
triax.goal1=triax.goal2=triax.goal3=-10000

#B. Activate flow engine and set boundary conditions in order to get permeability

flow.dead=0
flow.defTolerance=-1
flow.meshUpdateInterval=-1
flow.useSolver=3
flow.permeabilityFactor=1
flow.viscosity=10
flow.bndCondIsPressure=[0,0,0,0,1,1]
flow.bndCondValue=[0,0,0,0,100,0]
flow.boundaryUseMaxMin=[0,0,0,0,0,0]
flow.updateTriangulation=True
#O.dt=0.1e-4
#O.dynDt=False

newton.damping=0
#triax.wall_back_activated=0
O.run(2,1)
csdList=flow.getConstrictionsFull()
print(len(O.bodies),len(csdList),'finished')

flow.dead=1
for i in range(10,900):
    O.bodies.erase(i)
O.run(1000,1)

O.engines=O.engines[0:3]+O.engines[4:]

O.step()
O.step()
O.engines=O.engines[0:3]+[FlowEngine(dead=0,label="flow2"),]+O.engines[3:]
flow2.defTolerance = -1
flow2.meshUpdateInterval = -1
flow2.useSolver = 3
flow2.permeabilityFactor = 1
flow2.viscosity = 10
flow2.bndCondIsPressure = [0, 0, 0, 0, 1, 1]
flow2.bndCondValue = [0, 0, 0, 0, 100, 0]
flow2.boundaryUseMaxMin = [0, 0, 0, 0, 0, 0]
flow2.updateTriangulation=True
O.run(2,1)
csdList=flow.getConstrictionsFull()
print(len(O.bodies),len(csdList),'finished')

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