Coordination number for superquads

Submitted by Sounik on Sat, 03/09/2019 - 03:04

Hi Everyone,

It is possible for someone to let me know, the procedure to calculate coordination number (CN) for superquads?. Presently, I am using the compute for spherical particles, which is giving very high values (expected but unsure of the procedure) of CN.

As there are possibilities of face to face contacts in superquads as opposed to only point to point contact in spheres, I am wondering how it is being accounted for in the calculation.

Very much appreciated,
Sounik

Forums:

lumblab227 | Mon, 03/11/2019 - 07:14

How high would the CN be for superquadric considering the same porosity?

i.e. CN(SQ) = 7.5 & CN(sphere) = 5.6???

Sounik | Mon, 03/11/2019 - 07:34

Hi,

I prepared two samples with blockiness 2 and 3 using an identical sample preparation method with vertical compressive stress of 100kPa. Resulting void ratio and coordination numbers are 0.68, 4.3 and 1.1, 7.2 respectively.

I am surprised because though void ratios are increasing, coordination numbers also increased remarkably. Hence, I asked how is the coordination number computed for superquads in LIGGGHTS?

Thanks.
Sounik

medvedeg | Tue, 03/12/2019 - 14:06

I suspect current implementation of the coordination number is based on that for bounding spheres. That is why it delivers such big values. You can try to dump data from compute pair/gran/local. Number of entries in the dump files will be the number of contacts. Dividing this by twice number of particles will give you the coordination number.

Alexander Podlozhnyuk

Sounik | Tue, 03/19/2019 - 22:35

Dear Alexander,

Thank you. Is there any reference which talks about the procedure to calculate CN from bounding spheres?

Thanks
Sounik