New question #303013 on Yade:
https://answers.launchpad.net/yade/+question/303013
Hi, everyone
I want to use the engine Peri3dController to reach the goal state, but I
suffered some question. I used the identical initial condition, and used two
ways to reach the same goal of strain, but I got different results. The first
way is that I used the stressMask=0b011100 and goal=(0,-8e-4,0,0,0,0) and
nSteps = 8000 to compute once. The second way is that I used the
stressMask=0b011100 and goal=(0,-4e-4,0,0,0,0) and nSteps = 4000 to compute
twice by using strain=p3d.strain(imitating the example
peri3dController_triaxialCompression.py ). I thought that the final goal is
same, and the rate of applied strain is also same (goal/nSteps), so the final
stress should be same, too, should not it? But the final stress is different!
The following is my code, can you give me some suggestions? Thank you.
##################################### The initial condition
#!/usr/bin/python # This is server.py file
import string
from yade import plot,qt
from yade.pack import *
from yade import pack, plot
O.materials.append(CpmMat(young=150e9,frictionAngle=atan(0.8),poisson=.2,sigmaT=500e8,epsCrackOnset=1e-6,relDuctility=80000))
initSize=1.2
sp=pack.randomPeriPack(radius=.05,initSize=Vector3(initSize,initSize,initSize))
sp.toSimulation()
O.save('/tmp/tt.gz')
################################# The first way, using goal=-8e-4 and
nSteps=8000 to compute once
#!/usr/bin/python # This is server.py file
import string
from yade import plot,qt
from yade.pack import *
from yade import pack, plot
loadFile='/tmp/tt.gz'
O.load(loadFile)
O.dt=PWaveTimeStep()/2
plot.plots={'ex':('sx',)}
def plotAddData():
plot.addData(
sx=p3d.stress[1],
ex=p3d.strain[1],
)
EnlargeFactor=1.5
EnlargeFactor=1.0
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=EnlargeFactor,label='bo1s')]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=EnlargeFactor,label='ig2ss')],
[Ip2_CpmMat_CpmMat_CpmPhys()],[Law2_ScGeom_CpmPhys_Cpm()]),
NewtonIntegrator(),
Peri3dController(
nSteps=8000,
# how many time steps the simulation will last
# after reaching nSteps
do doneHook action
doneHook='print
"Simulation with Peri3dController finished."; O.pause()',
# the prescribed path
(step,value of stress/strain) can be defined in absolute values
# or in relative values
# if the goal value is
0, the absolute stress/strain values are always considered (step values remain
relative)plot.plots={'ex':('sx',)}
# if ##Path is not
explicitly defined, it is considered as linear function between (0,0) and
(nSteps,goal)
# as in yzPath and
xyPath
# the relative values
are really relative (zxPath gives the same - except of the sign from goal value
- result as yyPath)
# variables used in the
first step
label='p3d'
),
PyRunner(command='plotAddData()',iterPeriod=1),
]
p3d.stressMask=0b011100 # prescribed ex,ey,sz,syz,ezx,sxy; e..strain;
s..stress
p3d.goal=(0,-0.008,0,0,0,0) #xx, yy, zz, yz, zx, xy
O.step()
bo1s.aabbEnlargeFactor=ig2ss.interactionDetectionFactor=1.
O.run(); O.wait()
print "p3d.stress[0]"
print p3d.stress[0]
print "p3d.stress[1]"
print p3d.stress[1]
print "p3d.stress[5]"
print p3d.stress[5]
plot.saveDataTxt('8000.txt')
plot.plot(subPlots=False)
####################################### The second way, using goal=-4e-4 and
nSteps=4000 and strain=p3d.strain to compute twice
#!/usr/bin/python # This is server.py file
import string
from yade import plot,qt
from yade.pack import *
from yade import pack, plot
loadFile='/tmp/tt.gz'
O.load(loadFile)
O.dt=PWaveTimeStep()/2
plot.plots={'ex':('sx',)}
def plotAddData():
plot.addData(
sx=p3d.stress[1],
ex=p3d.strain[1],
)
EnlargeFactor=1.5
EnlargeFactor=1.0
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=EnlargeFactor,label='bo1s')]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=EnlargeFactor,label='ig2ss')],
[Ip2_CpmMat_CpmMat_CpmPhys()],[Law2_ScGeom_CpmPhys_Cpm()]),
NewtonIntegrator(),
Peri3dController(
nSteps=4000,
# how many time steps the simulation will last
# after reaching nSteps
do doneHook action
doneHook='print
"Simulation with Peri3dController finished."; O.pause()',
# the prescribed path
(step,value of stress/strain) can be defined in absolute values
# or in relative values
# if the goal value is
0, the absolute stress/strain values are always considered (step values remain
relative)plot.plots={'ex':('sx',)}
# if ##Path is not
explicitly defined, it is considered as linear function between (0,0) and
(nSteps,goal)
# as in yzPath and
xyPath
# the relative values
are really relative (zxPath gives the same - except of the sign from goal value
- result as yyPath)
# variables used in the
first step
label='p3d'
),
PyRunner(command='plotAddData()',iterPeriod=1),
]
p3d.stressMask=0b011100 # prescribed ex,ey,sz,syz,ezx,sxy; e..strain;
s..stress
p3d.goal=(0,-0.004,0,0,0,0) #xx, yy, zz, yz, zx, xy
O.step()
bo1s.aabbEnlargeFactor=ig2ss.interactionDetectionFactor=1.
O.run(); O.wait()
O.engines=[
ForceResetter(),
InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=1.0)]),
InteractionLoop(
[Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=1.0)],
[Ip2_CpmMat_CpmMat_CpmPhys()],[Law2_ScGeom_CpmPhys_Cpm()]),
NewtonIntegrator(),
Peri3dController(
# Vector6 of prescribed final values (xx,yy,zz, yz,zx,xy)
stressMask=0b011100, # prescribed ex,ey,sz,syz,ezx,sxy;
nSteps=4000, # how many time steps the simulation will last
# after reaching nSteps do doneHook action
doneHook='print "Simulation with Peri3dController finished."; O.pause()',
# the prescribed path (step,value of stress/strain) can be defined in absolute
values
# or in relative values
# if the goal value is 0, the absolute stress/strain values are always
considered (step values remain relative)
# if ##Path is not explicitly defined, it is considered as linear function
between (0,0) and (nSteps,goal)
# as in yzPath and xyPath
# the relative values are really relative (zxPath gives the same - except of
the sign from goal value - result as yyPath)
# variables used in the first step
label='p3d',
strain=p3d.strain
),
PyRunner(command='plotAddData()',iterPeriod=1),
]
p3d.goal=(0,-0.004,0,0,0,0)
print p3d.goal
O.run();O.wait()
print "p3d.stress[0]"
print p3d.stress[0]
print "p3d.stress[1]"
print p3d.stress[1]
print "p3d.stress[5]"
print p3d.stress[5]
plot.saveDataTxt('4000.txt')
plot.plot(subPlots=False)
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