LIGGGHTS® - User Forum

Does LIGGGHTS have a compute style to calculate the total unbalanced force in the system? Or better yet, a ratio of the total unbalanced force to the sum of all the contact forces? I use such a ratio in other programs to determine whether my simulation has reached a stable state, and I'd like to move onto using LIGGGHTS now.

Hi there,

I'm a master's student beginning to work with multispheres in LIGGGHTS.

I want to know what is the best way to do the Step 2 of this example: http://www.cfdem.com/multi-sphere-method-resolved-non-spherical-particles

Hi everyone,

hello,

i compiled the bondpackage model by Potyondy and Cundall and i could make the fracture simulation of a bonded particle model and also a simulation of a no bond breakage by specifying a very high bond-break radius.
But i haven't been able to simulate both behaviors at the same time for two bodies separately because i cant use a hybrid bond style with gran.

Can someone helpme with this?. i have little knowledge about c++ so its hard for me to hack de source code.

Any suggestion or question will be greatly appreciated.

Have a nice day,

Hallo everyone,

I am interested in charged particles and their interaction with an external field. (comparable with the video "Electrostatic" on this website). Can I use the efield command in Liggghts? And how can I define a charged particle (attribute q)?

Thanks for your help. Best wishes

Johannes

I understand that using command
fix xwalls1 all wall/gran model hertz tangential history primitive type 2 xplane 0.0
can create a infinite X-plane wall at x=0.

Could anyone tell me how to create a finite plane wall? For example, a wall from (0, 0) to (0, 2) in 2D or in 3D formed by 4 points.
Or it can only be done by importing mesh file?

Thanks!

Jason

hello,

I'm trying to insert particles in any region that you want, something like a custom region.

I was wondering if there is a software that can make a geometric figure and then export the file in VTK format for later use it as a mesh / tet in the region command.
Something similar when you make a figure using SolidWorks and then export the file in a stl format for use it as a mesh/surface.

Any suggestion or question will be greatly appreciated and I'm sure it will be considered.

Have a nice day,

zealakis.

Hi,

I try to count all collision events as a function of time in a granular system using contact/atom. This works fine. I get all contact events for each single particle and timestep, but in most cases the collision time is longer than one timestep. As a consequence of this multiple counts for one collision event are recorded. If I use larger timesteps I might miss some collision events.

Is there already any solution for this problem or has anyboy an idea how to fix it? I'm not a c++ expert, therefore it is difficult for me to change the source code.

Hello,

I would like to change how the CPUs are distributed along my simulation box. In particular I am interested in finding a way to change the type of seeding by which each CPU is allocated to a region of the simulation domain.

E.g. By using the command

processors 4 4 1

I will get 4 CPUs along x, 4 CPUs along y and 1 CPU along z. Each CPU will be allocated to a region of space given by:
domain length along x / CPUs along x
domain length along y / CPUs along y
domain length along z / CPUs along z

Dear friends,

The installation of Liggghts and CFDEM following the instruction on this website (git and cfdemCompLIG) was successful on my PC (Ubuntu 14/04).
However, when I tried to install it on our university's server (CENTOS 6.3), it always showed an error:
-lstdc++ -o ../lmp_fedora_fpic
ld: cannot find -lbat
make[1]: *** [../lmp_fedora_fpic] Error 1
Log file is also attached.

Could anyone please tell me how to solve it? Do I need to install the libbat.so or make a symbolic link or other ways?
Thanks!