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Re: [Question #673023]: setting initial velocity

To: yade-users@xxxxxxxxxxxxxxxxxxx
From: jacopo <question673023@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 28 Aug 2018 15:32:28 -0000
Reply-to: question673023@xxxxxxxxxxxxxxxxxxxxx
Sender: bounces@xxxxxxxxxxxxx
Question #673023 on Yade changed:
https://answers.launchpad.net/yade/+question/673023

    Status: Answered => Open

jacopo is still having a problem:
Hi jan, thanks for your help. I modified the script as you suggest me
and it is working (when the box hits the soil, it decelerates and
breaks). As you said i need to clump it, but i'm facing this error:

python: /build/yade-2_s9R0/yade-1.20.0/core/Clump.cpp:211: static void Clump::updateProperties(const boost::shared_ptr<Body>&, unsigned int): asserzione "M>0" non riuscita.
Annullato (core dump creato)

i provide a minimal script:

#####################################
########### BOX 1 ###################
#####################################


facets=geom.facetBox((4,0,0),(1.2,1.2,1.2),wallMask=63)
clumpID = O.bodies.appendClumped(facets)
clump = O.bodies[clumpID] 


for b in O.bodies:
    b.dynamic=True
    b.state.mass=1
    b.state.inertia=(0.1,0.5,0.4)
    b.fixed=True

################
##box material##
################

idCA=FrictMat(density=2227,frictionAngle=radians(0.5),label='CA',young=30e9,poisson=0.15)
O.materials.append(idCA)

############################
####### BOX 2 ##############
############################


O.bodies.append(geom.facetBox((0,0,0),(2,2,2),wallMask=29)) 


#################
##soil material##
#################

idSoil=FrictMat(density=1500,frictionAngle=radians(29),label='soil',young=11277647.5,poisson=0.21)	
O.materials.append(idSoil)

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

pred=pack.inAlignedBox((-2,-2,-2),(2,2,2))
spheres=pack.regularHexa(pred,radius=0.1,gap=0)
O.bodies.append(spheres)


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

O.engines=[
   ForceResetter(),
   InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()]),
   InteractionLoop(
      [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom()],
      [Ip2_FrictMat_FrictMat_FrictPhys()],
      [Law2_ScGeom_FrictPhys_CundallStrack()]
   ),
 #TranslationEngine(translationAxis=(-1,0,0),velocity=18,ids=lista,label='trans'),
 NewtonIntegrator(gravity=(0,0,-9.81),damping=0),
 PyRunner(command='inizio()',iterPeriod=1),
]

################
####funzioni####
################

def inizio():
     if O.iter < 2:
       for i in range(0,12) :
           O.bodies[i].state.vel=(-18,0,0)


O.dt=0.8*PWaveTimeStep()
O.saveTmp()
########################################
########################################





->NOTE:
changing the first part of the script "BOX 1" with the following script you could see what i'm trying to do:

#####################################
########### BOX 1 ###################
#####################################

O.bodies.append(geom.facetBox((4,0,0),(1.2,1.2,1.2),wallMask=63))

for b in O.bodies:
    b.dynamic=True
    b.state.mass=10
    b.state.inertia=(0.1,0.5,0.4)
    b.fixed=True

In particular, in my project, i have a much more complicated shape then a box. If i use the same identical logic of the provided script i can observe that my object is still moving at the same velocity . I try to explain better: while the first part of my object hits the soil and starts to decelerate and break itself,  the not in contact parts continue their movement with the same starting velocity. My question is :
->  clumping all my object facets, will they start to decelerate even if they aren't directly in contact with the soil?  

I'm sorry for the last questions, i read the guidelines, i hope to not
make any other mistakes.

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