Hey Chris,
There has been a recent paper published in Powder Technology: An investigation of the comparative behaviour of alternative contact force models during elastic collisions (2011) C Thornton, S J Cummins, P W Cleary; which may be of interest for you.
In a nutshell it says that the Hertz model (used in LIGGGHTS code) is fine for macroscopic behaviour , but smaller scales may show some obscurities. It suggests that the tangential forces should be calculated incrementally as per equation 39 in this paper. The Hertz model tends to result in a smaller reversal of the surface velocity, less spin imparted to the sphere and a higher tangential coefficient of restitution.
Also I know that Thornton is producing another paper soon that shows that in a spring-dashpot model, the tangential dashpot should be omitted to obtain reliable results.
I wanted to know your thoughts on the content of this paper, and how the LIGGGHTS code stands up to the suggested 'correct' model in this paper, although it is stated in their conclusion that systems with enduring contacts needs further study.
Jay
ckloss | Thu, 05/19/2011 - 13:16
Hi Jay, thanks for the
Hi Jay,
thanks for the reference, I did not know that paper, but the outline of that paper is not new to me.
So yes, it would be good to have such a model - and by harnessing object orientation, it would be quite easy to implement it. If you would be interested in doing this, we could make a joint publication on that - in that case, contact me via boardmail.
Christoph
jwarnett | Fri, 05/20/2011 - 16:11
I have messaged through the
I have messaged through the contact page in your profile. If that isn't the way you mean't just drop me and email
Jay
ckloss | Mon, 05/23/2011 - 14:45
Hi Jay, yes, that was the way
Hi Jay,
yes, that was the way I mean - will come back to you tomorrow.
Cheers,
Christoph
PS: I removed your email from the message (just to keep you spam free)