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Re: Elastic energy


Václav Šmilauer said:     (by the date of Mon, 05 Jul 2010 15:02:00 +0200)

> E.g. if you slide 2 spheres back and
> forth, then each cycle dissipates energy, which will never come back.

exactly. this is why I am so surprised. Notice my three ??? in my
previous post ;)
> (If an interaction is broken, then it is a different issue, i.e. that
> dissipated energy of broken interactions should be saved somehow, since
> otherwise we lose the number).

the calculation of plasticDissipation is incremental. If the contact
breaks, then nothing is lost, you only stop incrementing it.

Bruno Chareyre said:     (by the date of Mon, 05 Jul 2010 15:21:22 +0200)

> >>  Look at the elastic energy, it's
> >> almost zero, how is it possible that kinetic energy is increasing?
> >>   
> > Thats right, kinetic should never increase with this script.
> >
> I should have say it can't increase in average. It can still increase 
> after the peaks in ElastE.

Kinetic energy is increasing, and it never should. But plasticDissipation()
as I have shown on the graph increases only when kinetic goes down.

So maybe the mistake is not in plasticDissipation, but in kinetic energy?

The contact breaks and suddenly the sphere gets big velocity, but it
shouldn't? It would be worth checking both velocity and angular velocity.

Janek Kozicki                               http://janek.kozicki.pl/  |

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