yade-dev team mailing list archive

[Chiara Modenese <c.modenese@xxxxxxxxx>]

Hi,

can you past and copy here the NUMBERS you get after ONE time step as Bruno
suggested (please, read again his previous comment)? I mean: please print
FORCES, POSITIONS and VELOCITIES.

Regards,
Chiara


On 13 July 2011 13:32, Christian Jakob <806944@xxxxxxxxxxxxxxxxxx>
wrote:

> Hello again,
>
> Thank you for your answers. It helps me very much.
>
> I compared PFC and YADE again with another simple test. Again there are two
> spheres and the upper one gets an initial velocity. During contact velocity,
> distance and forces are monitored. Unfortunately I could not catch the
> forces right now... any idea, how to do this?
> Configurations, parameters and time steps are the same in both programs.
>
> Nevertheless the velocity indicates, that PFC and YADE do not behave the
> same way (even without any damping).
> You can see that, when you compare velocity-time-no-damping-yade.png (from
> yade) with velocity-time-no-damping.bmp (from pfc) and
> velocity-time-visc-0-1-yade.png (from yade) with
> velocity-time-visc-1.00000000000e-001tension0.bmp (from pfc). Please note,
> that I increased number of cycles in yade in the damped case
> (visc_damp_normal = 0.1, line 14) to 700 to see the effect of tension force.
>
> So my conclusion is, that both programs behave different and can lead to
> different output. Therefore this is not a bug and I will set the status
> of to 'fixed'.
>
> Regards,
>
> Christian
>
> ** Attachment added: "viscoelastic-test.tar.gz"
>
> https://bugs.launchpad.net/yade/+bug/806944/+attachment/2205401/+files/viscoelastic-test.tar.gz
>
> ** Changed in: yade
>       Status: New => Fix Released
>
> --
> You received this bug notification because you are a member of Yade
> developers, which is the registrant for Yade.
> https://bugs.launchpad.net/bugs/806944
>
> Title:
>  different behavoir of Hertz model while comparing PFC and YADE
>
> Status in Yet Another Dynamic Engine:
>   Fix Released
>
> Bug description:
>  Hello,
>
>  During verifiing my model I compared output from PFC 4.0 with the
>  output from YADE (bzr2877 on Debian Squeeze 64bit). There I found a
>  different behavior between these two programs. I dont know if this is
>  a bug or not, but I hope someone can explain the different behavior.
>
>  The model itself is very simple. There are two spheres, an upper one and a
> lower one. The lower one is fixed and the upper one is falling down to the
> lower one, collides and jumps back. The value of interest is the flyback
> height of the upper particle.
>  In PFC I measure higher values of flyback height, then in YADE (see
> log-files in the attachment).
>
>  Can someone tell me why there is a difference in the flyback height?
>  (input parameters are the same for both programs ... see
> caller_two-spheres-jumping.dat for PFC and two-spheres.py for YADE)
>
>  Regards,
>
>  Christian Jakob
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/yade/+bug/806944/+subscriptions
>
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-- 
You received this bug notification because you are a member of Yade
developers, which is the registrant for Yade.
https://bugs.launchpad.net/bugs/806944

Title:
  different behavoir of Hertz model while comparing PFC and YADE

Status in Yet Another Dynamic Engine:
  Fix Released

Bug description:
  Hello,

  During verifiing my model I compared output from PFC 4.0 with the
  output from YADE (bzr2877 on Debian Squeeze 64bit). There I found a
  different behavior between these two programs. I dont know if this is
  a bug or not, but I hope someone can explain the different behavior.

  The model itself is very simple. There are two spheres, an upper one and a lower one. The lower one is fixed and the upper one is falling down to the lower one, collides and jumps back. The value of interest is the flyback height of the upper particle.
  In PFC I measure higher values of flyback height, then in YADE (see log-files in the attachment).

  Can someone tell me why there is a difference in the flyback height?
  (input parameters are the same for both programs ... see caller_two-spheres-jumping.dat for PFC and two-spheres.py for YADE)

  Regards,

  Christian Jakob

To manage notifications about this bug go to:
https://bugs.launchpad.net/yade/+bug/806944/+subscriptions