LIGGGHTS® - User Forum

I have recently started using lammps and am trying to simulate granular poiseuille flow using the LIGGGHTS. Now I want to use gran/hooke as pair_style but it showed me the following error on compilation "Illegal fix property/global command, not enough arguments (fix_property_global.cpp:50)", though I have used all the fixes for the gran/hooke pairt_style. including the coefficient of restitution, young's modulus, poisson's Ratio ,characteristic velocity and coefficient of friction.

Hi,

I'm going to simulate a cylinder with the bottom lid as a rotating disk. I do not need mesh. Is it possible to declare the region in this way or I have to import CAD ?

Thank you in advance for your assistance

Hello, Christophe, Hello all,
Is elasto-plastic pair style implemented in Liggghts? Thank you
Cheers,
Zyan

Hi Christoph, Hi LIGGGGHTSers,
Rencently, i am working on simulations of stirring a peller (steel) in a vassel with particles (radii =1 mm, glass beans ). The simulation behave strangely, withparticles flowing everywhere out of control (cf. attached figure: bad_normal_e). The properties are given at the bottom.

Hi.

I have a question

I want to calculate the collision energy between balls in a ball-mill.
So I'm trying get the value of the kinetic energy of balls when a ball contacts another ball.

The condition of atom type is granular,

I have used "compute pair/gran/local command ",

as describe below

compute pa all pair/gran/local id

and, I've gotten the IDs of balls(atoms) which contacts another balls with as c_pa[1], and c_pa[2].

I want to make group which have the atom IDs in c_pa[1], and c_pa[2] ,but i couldn't that.

Hi,

when I try to use addtorque on particles there occurs an error with 'too many neighborbins (neighbor.cpp:1747)'.
Without the addtorque its working. To use addtorque I went before in the src directory and did 'make yes-user'. Then make clean-all and make fedora. It is now running a few timesteps but then the error occurs. Is there maybe a better way then using addtorque?

thanks
Joshua

Hi everyone,

I noticed that a lot of papers suggested reducing Young's modulus (shown in Hertz contact model) by several orders in Engineering modeling. But I didn't find any guideline on how many orders are proper in doing this, especially for a binary system. Can anyone give me some reference? Thanks.

Dear Liggghts users,

I am having three problems counting the number of particles of 2 different sizes flowing through a rectangular slot. My Liggghts version is 2.3.6.

The first problem is that when I use group function with variable function as shown below in the input script, the output of particle count is always zero. I don't quite understand why this happens. (Here I simplify the problem by using fewer timesteps and try to count to particle in the insert region, named as inbox.)

Here is the script I wrote:

Hello,
I'm new at Liggghts. So far I worked with the continuous mixer tutorial.
After a few tries and errors, I managed it, to work under Liggghts 3.0.3.
At the moment I try to get the time of creation of every particle to be written in the dump file.
I searched for some clues, but I didn't find anything.

I hope somebody can help me.

Thanks.
RobertG.

Dear Colleagues,
I would like to esxport the displacement of the moving mesh when using commmand fix mesh/surface/stress/servo. Is there a way to do this?
Thank you.
Best regards,
ZYan