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[Jan Stránský <question305894@xxxxxxxxxxxxxxxxxxxxx>]

Question #305894 on Yade changed:
https://answers.launchpad.net/yade/+question/305894

Jan Stránský proposed the following answer:
Hi James,

according to docs [1,2], one option is ti use
Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(...,
*recordCracks=True,Key='test'*)
It should not be difficult to add some more information in the source code.

another option (with some modifications also applicable to different
materials) is to use a python function and call it with PyRunner. For this
purpose, set (Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(...,
*neverDamage=True*) [3] to make broken interactions still exist and make
possible to get information form them ("crack width" etc.)

###################################
def processBrokenInteractions():
print
print 'iter',O.iter
for i in O.interactions:
if i.phys.isBroken:
b1 = O.bodies[i.id1]
b2 = O.bodies[i.id2]
w = i.phys.initD-i.geom.penetrationDepth # not 100% sure
print 'cp',i.geom.contactPoint,'mat',b1.mat,'normal',i.geom.normal,'width',w
# write to file instead of print possible
# extract whatever you want from the interaction i
###################################

cheers
Jan

[1]
https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM.recordCracks
[2]
https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM.Key
[3]
https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM.neverErase


2016-07-28 0:43 GMT+02:00 James X <question305894@xxxxxxxxxxxxxxxxxxxxx>:

> Question #305894 on Yade changed:
> https://answers.launchpad.net/yade/+question/305894
>
> James X posted a new comment:
> Hi Jan,
>
> Thank you very much. I have included a simplified version of what I am
> trying to do.  It is currently a pseudo-2D simulation, though I would
> ideally like to be able to handle both 3D and 2D. What I would hope for
> is to be able to export, at any user-defined timestep, the fracture
> event coordinates, the coordinates of the element pair that broke, and
> the material of the two elements.
>
> However, having just the coordinates of the fracture event themselves
> itself would be great.
>
> Just as a FYI, the first half is just a 2D gravity-settling script to
> generate a 2D mesh. While I would like to do 3D simulations, the
> limitations of my experimental data does not allow me to go 3D at the
> moment.
>
>
> import numpy as np
> import time
>
> from yade import pack
> from yade import geom
> from yade import polyhedra_utils
> from yade import utils
> from yade import linterpolation
> from yade import export
> from yade import ymport
>
> #other random parameters
> start = time.time()
>
> #this function just makes a 2D sphere mesh and exports it as
> <FILENAME>.sphere
> def Make_Packed_file(filename, xSize, ySize, radius, rRelFuzz_value,
> nbIter=3000):
>     #filename = filename #output a msh file
>     sp=pack.SpherePack()
>
> sp.makeCloud(minCorner=(0,0,0),maxCorner=(xSize,ySize*2.5,0),rMean=radius,
> rRelFuzz = 0)
>     sp.toSimulation()
>     for b in O.bodies:
>         b.state.blockedDOFs = 'zXY'
>
> box=O.bodies.append(utils.geom.facetBox((xSize/2,1.25*ySize,0),(xSize/2,1.25*ySize,radius),wallMask=63))
> # the same box of makeCloud
>
>     O.engines=[
>         ForceResetter(),
>
> InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb(),Bo1_Wall_Aabb()]),
>         InteractionLoop(
>
> [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom(),Ig2_Wall_Sphere_ScGeom()],
>         [Ip2_FrictMat_FrictMat_FrictPhys()],
>         [Law2_ScGeom_FrictPhys_CundallStrack()]
>         ),
>         NewtonIntegrator(gravity=(0,-2.0,0),damping=.1),
>         PyRunner(iterPeriod=500,initRun=False,command='print("elapsed time
> is: " + str(time.time() - start) ) '),
>
> DomainLimiter(lo=(-0.01,-0.01,-0.01),hi=(xSize,ySize,1.1*radius),iterPeriod=nbIter-1)
>     ]
>     O.dt=utils.PWaveTimeStep()
>     O.stopAtIter=nbIter
>     O.run()
>     O.wait()
>     export.text(filename+'.spheres')
>
>
> ###random parameters
> radius = 3
> smoothContact=True
> jointFrict=radians(20)
> jointDil=radians(0)
> new_scale = 1.0
> xSize = 250;
> ySize = 150;
> rRelFuzz_value = 0;
>
> #actually make this packed mesh
> Make_Packed_file("simplified_packed_2D_mesh", xSize, ySize, radius,
> rRelFuzz_value)
>
> O.reset() #reset everything, just in case
>
>
> #defin the material
> def mat_1(): return
> JCFpmMat(type=1,young=30.0e9,poisson=0.3,frictionAngle=radians(30),density=3000,tensileStrength=1.23e8,cohesion=1.23e8,jointNormalStiffness=1e7,jointShearStiffness=1e7,jointCohesion=1e6,jointFrictionAngle=radians(20),jointDilationAngle=0.0)
>
>
> O.materials.append((mat_1()))
>
> #import the mesh created in the previous simulation
> import_spheres =
> ymport.text("simplified_packed_2D_mesh.spheres",scale=new_scale,shift=Vector3(0,0,0),material=mat_1)
> O.bodies.append(import_spheres)
>
>
> #add in wall information, from uniax.py
> young = 90e9
> mn,mx=Vector3(0,0,0),Vector3(xSize*new_scale,1.01*ySize*new_scale,2.00001*radius)
> # corners of the initial packing
>
> 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)
>
>
> #from uniax.py
> bb=uniaxialTestFeatures()
>
> negIds,posIds,axis,crossSectionArea=bb['negIds'],bb['posIds'],bb['axis'],bb['area']
>
> strainRateTension=.05
> setSpeeds=True
>
>
> interactionRadius=1.60 # to set initial contacts to larger neighbours and
> a bit further
>
> O.engines=[
>
>         ForceResetter(),
>
> InsertionSortCollider([Bo1_Sphere_Aabb(aabbEnlargeFactor=interactionRadius,label='is2aabb'),]),
>         InteractionLoop(
>
> [Ig2_Sphere_Sphere_ScGeom(interactionDetectionFactor=interactionRadius,label='ss2d3dg')],
>
> [Ip2_JCFpmMat_JCFpmMat_JCFpmPhys(cohesiveTresholdIteration=1,label='interactionPhys')],
>
> [Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM(smoothJoint=smoothContact,label='interactionLaw')]
>         ),
>         GlobalStiffnessTimeStepper(timestepSafetyCoefficient=0.8),
>         NewtonIntegrator(damping=0.2,gravity=(0.,0,0.)),
>
> UniaxialStrainer(strainRate=strainRateTension,axis=axis,asymmetry=0,posIds=posIds,negIds=negIds,crossSectionArea=crossSectionArea,blockDisplacements=False,blockRotations=False,setSpeeds=setSpeeds,label='strainer'),
> ]
>
> #### time step definition (low here to create cohesive links without big
> changes in the assembly)
> O.dt=0.05*utils.PWaveTimeStep()
>
> #### set cohesive links with interaction radius>=1
> O.step();
>
> #### initializes now the interaction detection factor to strictly 1
> ss2d3dg.interactionDetectionFactor=-1.0
> is2aabb.aabbEnlargeFactor=-1.0
>
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