How to change the strainRate value of TriaxialCompressionEngine during the simulation period?

Most studies on strain rate effects on shearing behavior of saturated clay have employed quasi-static triaxial compression tests under strain-controlled conditions, potentially with either pore water pressure measurements, or impulse loading compression tests which were under stress-controlled conditions.
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Hello,

I would like to help you, but will you please separate your questions so that we can answer them individually? One question per thread, thank you so much for taking the time to read [2] to understand how we are working to make this knowledge base sustainable and reusable for future users.

As we point out in [1]:

"Warning This engine is deprecated, please switch to TriaxialStressController if you expect long term support."

So I would suggest you switch to TriaxialStressController.

Cheers,

Robert

[1]https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.TriaxialCompressionEngine
[2]https://www.yade-dem.org/wiki/Howtoask

Thank you Robert, I have changed the engine I use from TriaxialCompressionEngine to TriaxialStressController,

My code is below.

This code can run normally, but it still cannot make the cyclic loading realizable.

[1] So I would like to know how to change the parameters in the TriaxialStressController engine while the simulation is running? (Like change the triax.goal1 and tiax.goal2 and the stressMask?

###############

from yade import pack
# The following 5 lines will be used later for batch execution
nRead=readParamsFromTable(
 num_spheres=1000,# number of spheres
 compFricDegree = 30, # contact friction during the confining phase
 key='_triax_base_', # put you simulation's name here
 unknownOk=True
)
from yade.params import table

num_spheres=table.num_spheres# number of spheres
key=table.key
targetPorosity = 0.43 #the porosity we want for the packing
compFricDegree = table.compFricDegree # initial contact friction during the confining phase (will be decreased during the REFD compaction process)
finalFricDegree = 30 # contact friction during the deviatoric loading
rate=-0.02 # loading rate (strain rate)
damp=0.2 # damping coefficient
stabilityThreshold=0.01 # we test unbalancedForce against this value in different loops (see below)
young=5e6 # contact stiffness
mn,mx=Vector3(0,0,0),Vector3(10,10,.1) # corners of the initial packing

## create materials for spheres and plates
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'))

## create walls around the packing
walls=aabbWalls([mn,mx],thickness=0,material='walls')
wallIds=O.bodies.append(walls)

## use a SpherePack object to generate a random loose particles packing
sp=pack.SpherePack()

sp.makeCloud(minCorner=mn,maxCorner=mx,rRelFuzz=0,num=2000)
sp.toSimulation(material='spheres')

triax=TriaxialStressController(

 maxMultiplier=1.+2e4/young, # spheres growing factor (fast growth)
 finalMaxMultiplier=1.+2e3/young, # spheres growing factor (slow growth)
 thickness = 0,

 internalCompaction=False,

 stressMask = 1,
        goal1=-2e5,
 goal2=rate,

 )

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()]
 ),
 GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.8),

 triax,

 TriaxialStateRecorder(iterPeriod=100, file='WallStresses.txt'),
 NewtonIntegrator(damping=damp),
 PyRunner(command='triaxload()',iterPeriod=1, label='triaxload'),

 #PyRunner(command='triaxload()',realPeriod=2, label='triaxload')
]

triax.stressMask = 1
triax.goal1=-2e5
triax.goal2=rate

def triaxload():
        O.triax.goal1=-3e5
 if abs(O.triax.stress(triax.wall_top_id)[1])> 150000:
  O.triax.stressMask = 1
  O.triax.goal1=-3e5
  O.triax.goal2=rate
  triaxload.command=('triaxunload')

def triaxunload():
 if abs(triax.stress(triax.wall_top_id)[1])< 5e4:
  triax.stressMask = 1
  triax.goal1=-1e5
  triax.goal2=rate

from yade import plot

O.engines=O.engines[0:5]+[PyRunner(iterPeriod=20,command='history()',label='recorder')]+O.engines[5:7]
def history():
 plot.addData(e11=-triax.strain[0],
         e22=-triax.strain[1],
  s11=-triax.stress(triax.wall_right_id)[0],
  s22=-triax.stress(triax.wall_top_id)[1],

  i=O.iter)

plot.plots={'e11': ('s11',),'e22': ('s22',)}

O.saveTmp()
plot.plot()

Please do not repeat yourself in two different questions (here and https://answers.launchpad.net/yade/+question/700957)

https://answers.launchpad.net/yade/+question/701030

I just solved this problem.