Hi everyone,
I'm confusing with cohesion energy density in the pair_gran_hooke_history. As I understand cohesion energy density is the work needed to separate the whole volume of particle in contact. So how to calculate cohesion energy density if Van der waals adhesion is taken into account? And where is cohesion energy density in original JKR model?
Many thanks for your help!
Best regards,
Duy
ckloss | Wed, 04/10/2013 - 08:23
Hi Duy,
Hi Duy,
the cohesion energy density in LIGGGHTS is a (constant) numerical parameter. The energy needed to separate 2 cohesive particles depends e.g. on the initial overlap. So typically, calibrating the model with some experiments is what we typically do.
Best,
Christoph
nquangd | Wed, 04/10/2013 - 11:03
Hi Christoph
Hi Christoph,
Thank you very much for your comment. I have two more points that need your help!
(1) It makes sense to me that cohesion energy density is related to surface energy density which is also depends on an experimental value of separation distance D. Can we link the cohesion energy density in LIGGGHTS with the surface energy density w? assuming that we already know the separation distance, and of course, the surface energy density
(2) And if I would like to follow the original JKR model, which F adhesion can be calculated from surface energy, contact radius and normal overlap, it means that a new pair style is needed? or we can follow the pair_style gran/hertz/history style if (1) is solved?
Best regards,
Duy
ckloss | Fri, 04/19/2013 - 15:22
>>And if I would like to
>>And if I would like to follow the original JKR model, which F adhesion can be calculated
>>from surface energy, contact radius and normal overlap, it means that a new pair style is needed?
yes
Christoph