Mass for walls

Submitted by ykusaka on Thu, 08/16/2018 - 13:30

Hi,

To my understanding, Meff (effective mass) used in contact models can be calculated from "density" defined in

fix pts1 all particletemplate/sphere ...

but I have questions as follows:

1. I need to know how to define the mass for walls including mesh to be used in Meff.

2. please let me know If there is a way to directly define Meff used in hertz/stiffness or hooke/stiffness (I want to set it unity for simplicity).

Thank you

richti83's picture

richti83 | Fri, 08/17/2018 - 19:52

for walls only the particle mass is used:
https://github.com/CFDEMproject/LIGGGHTS-PUBLIC/blob/master/src/fix_wall...
which goes from https://github.com/CFDEMproject/LIGGGHTS-PUBLIC/blob/master/src/fix_wall...
to https://github.com/CFDEMproject/LIGGGHTS-PUBLIC/blob/master/src/normal_m...

I think as the wall is non-defermable only radius of particle and particle mass is relevant in DEM.

About 2.: yes mass is directly calculated from density, so when you know your particle radius you can calculate volume and than the needed density for unity mass.

I'm not an associate of DCS GmbH and not a core developer of LIGGGHTS®
ResearchGate | Contact

ykusaka | Sun, 08/26/2018 - 09:11

Thank you for your very comprehensive guidance.