# yade-users team mailing list archive

## Re: Elastic energy

• From: Janek Kozicki <janek_listy@xxxxx>
• Date: Sun, 4 Jul 2010 10:13:46 +0200

```chiara modenese said:     (by the date of Fri, 2 Jul 2010 23:34:21 +0000)

> > > decreases and no slip occurs since the function plasticDissipation() of
> > > Law2_ScGeom_FrictPhys_Basic contact law returns 0. I have already checked
> > on
> > > paper and discussed with Bruno and the code which computes
> > > plasticDissipation in ScGeom is formally correct.
> >
> > How about heat? Usually friction increases temperature of those
> > bodies that are in friction. But in yade we don't have heat, so this
> > turns into an energy loss.
> >
> In fact there is no heat effect at all in Yade, Janek could you elaborate
> your thought? Energy must be conserved as long as the system is closed. I am
> trying to see in a TT simulation what happens. Bruno, have you tried it?
> Actually I am thinking to inlcude in the TTRecorder the various energy
> terms, mechanical energy and so on.

heat from friction should proportional to the total path that has
slipped. A simplest way to track that is to just keep track of how
long distance [m] everything has slipped, and use some conversion
from distance to energy, due to friction. Eg. calculate the work: W=F*x.

Better stay with energy than go to heat & temperature, because if you
decided to go into thermodynamics, you will add a work worth of a
second PhD to what you are already doing. Heat transfer, specific
heat capacity, phase changes (a molten sphere?) and all that stuff.

It appears that plasticDissipation() counter is almost what you need
here - the simpler (non thermodynamic) approach which I mentioned
above. I didn't know about it - when did you add this? (time to