Asking for script of particle crushing

Hi. I have two questions.

First, I would like to simulate crushing between a particle and a group of RandomBlock particles, but the following code does not work well. The RandomBlock particles disperse from the beginning. Note, the RandomBlock particles do not disperse but stay connected in the simulation case without the single RotSphere particle.
==============
#import the appropriate ESyS-Particle modules:
from esys.lsm import *
from esys.lsm.util import *
from esys.lsm.geometry import *

#instantiate a simulation object:
sim = LsmMpi (numWorkerProcesses = 4, mpiDimList = [2,1,2])

#initialise the neighbour search algorithm:
sim.initNeighbourSearch (
 particleType = "RotSphere",
 gridSpacing = 2.5000,
 verletDist = 0.0400
)

#set the number of timesteps and timestep increment:
sim.setNumTimeSteps (50000000)
sim.setTimeStepSize (1.0000e-06)

#specify the spatial domain for the simulation
domain = BoundingBox(Vec3(-20,-20,-20), Vec3(20,20,20))
sim.setSpatialDomain (domain)

#add a particle
particle=RotSphere(id=1, posn=Vec3(0,5.5,0), radius=2.0, mass=10.0)
particle.setLinearVelocity(Vec3(0.0,-2.0,0.0))
sim.createParticle(particle)

#create a prism of spherical particles:
geoRandomBlock = RandomBoxPacker (
 minRadius = 0.500,
 maxRadius = 1.0000,
 cubicPackRadius = 2.2000,
 maxInsertFails = 5000,
 bBox = BoundingBox(
  Vec3(-6.0000, 0.0000,-6.0000),
  Vec3(6.0000, 2.5000, 6.0000)
 ),
 circDimList = [False, False, False],
 tolerance = 1.0000e-05
)
geoRandomBlock.generate()
geoRandomBlock_particles = geoRandomBlock.getSimpleSphereCollection()

#add the particles to the simulation object:
sim.createParticles(geoRandomBlock_particles)

#bond particles together with bondTag = 1:
sim.createConnections(
 ConnectionFinder(
  maxDist = 0.1,
  bondTag = 1,
  pList = geoRandomBlock_particles
 )
)

#create rotational elastic-brittle bonds between particles:
pp_bonds = sim.createInteractionGroup (
 BrittleBeamPrms(
  name="pp_bonds",
  youngsModulus=1000000.0,
  poissonsRatio=0.25,
  cohesion=100.0,
  tanAngle=1.0,
  tag=1
 )
)

#initialise frictional interactions for unbonded particles:
sim.createInteractionGroup (
 FrictionPrms(
  name="friction",
  youngsModulus=100000.0,
  poissonsRatio=0.25,
  dynamicMu=0.4,
  staticMu=0.6
 )
)

#create an exclusion between bonded and frictional interactions:
sim.createExclusion (
 interactionName1 = "pp_bonds",
 interactionName2 = "friction"
)

#add translational viscous damping:
sim.createInteractionGroup (
 LinDampingPrms(
  name="damping1",
  viscosity=0.002,
  maxIterations=50
 )
)

#add rotational viscous damping:
sim.createInteractionGroup (
 RotDampingPrms(
  name="damping2",
  viscosity=0.002,
  maxIterations=50
 )
)

#execute the simulation:
sim.run()
==============

Second, I'm writing journal papers on DEM simulation using ESyS-Particle. Do you have any recommended citation about ESyS-Particle?