How to assign diiferent properties to walls

Hi,

I cannot manage to give different properties to walls. in my simulations walls and particles are of two different materials.
I tried to assign different group ID to boundaries and particles but I get a command error which I don't find it.

Thanks
Mohammad

Forums:

LIGGGHTS® - User Forum

cstoltz | Tue, 06/09/2015 - 21:46

Could you post your input deck?

Could you post your input deck to see if there are any obvious errors?

Regards,
Chris

richti83 | Thu, 06/11/2015 - 14:53

you need different atom types

.. create_box 3 reg ... #import triangular mesh fix cad1 all mesh/surface file mesh.stl type 2 scale 0.001 fix cad2 all mesh/surface file mesh.stl type 3 scale 0.001 #use the imported mesh as granular wall fix granwalls all wall/gran/hooke/history mesh n_meshes 2 meshes cad1 cad2
and off course appropriate fixes of m4 all property/global coefficientFriction peratomtypepair 3 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3
for atom types 1=particle,2=wall, 3=another wall

mkt1363 | Wed, 06/24/2015 - 10:57

Could particle-wall coefficients be diffrent from wall-particle?

Thanks I tried it and it works well. but I still have a question. What does that mean if you set diffrent values for 2-1 and 1-2. I tried it and there is no error but in my sense they should be the same.

Mohammad

aaigner | Wed, 06/24/2015 - 14:48

Correct...

Hi Mohammad!

From a technical point of view the matrix is symmatric for all materials. It does not make sense to destinguish between an interaction of 1-2 and 2-1. Nevertheless the code allows you to define those properties independently. If it is not a bug, it is a feature. ;-)

Bests
Andreas