Yade

How do I keep the particles still?

Asked by 孙灿

I needed to keep all the particles in the simulation still, so I used the following code:
def checkUnbalanced():
 if unbalancedForce() < .02:
  O.pause()
                for b in O.bodies:

                    if isinstance(b.shape,Sphere):
                        b.state.blockedDOFs='zxy'
checkUnbalanced() is a function I define.
But I found that the particles are not fixed, why is that? Is there any other code that keeps particles immobile?

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Jan Stránský (honzik) said : 		#1

Hello,

> state.blockedDOFs='zxy'

this blocks degrees of freedom from being influenced by interactions.
But, it still allows to set velocity and has no influence on current velocity.
So the result is that the current velocity is preserved (it is not influenced by interactions any more).

To immobilize a particle, set zero velocity and angular velocity
b.state.vel = (0,0,0)
b.state.angVel = (0,0,0)

You can use predefined function
calm() # [1]
to immobilize all particles

Cheers
Jan

[1] https://yade-dem.org/doc/yade.utils.html#yade._utils.calm

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孙灿 (suncan) said : 		#2

I tried adding b.state.vel = (0,0,0), b.state.angVel = (0,0,0) and the particles did stay still, but new problems arose. I wanted to use O.boides.append() to add some particles while the original particles remained stationary, but I don't know why, some particles may fall down and partially overlap with the particles added by O.boides.append().

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Jan Stránský (honzik) said : 		#3

> new problems arose

please open a new question for a new problem ([2], point 5)

Cheers
Jan

[2] https://www.yade-dem.org/wiki/Howtoask

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Launchpad Janitor (janitor) said : 		#4

This question was expired because it remained in the 'Open' state without activity for the last 15 days.