LIGGGHTS® - User Forum

I am using LIGGGHTS on a bluegene/p cluster and when I attempt to run a simulation I get an error that reads:

Could not locate a fix/property storing value(s) for youngsModulus as requested by gran/hooke. (modify_liggghts.cpp:247)

I checked with the sysadmin and he has told me that there is nothing wrong with the installation. I have version 2.3.5 installed. Any help or direction at all would be greatly appreciated.

Hi,

I am wondering how the adhesion between the particles and the wall is treated. I have set up my simulation with 3 different types, 1 is the particles, 2 is the walls, and 3 is for a no friction/no adhesion symmetry plane. I have specified the cohesion as:

fix m6 all property/global cohesionEnergyDensity peratomtypepair 3 &
1000000 1000000 0000001 &
1000000 0000001 0000001 &
0000001 0000001 0000001

I am using the sphere type for the granular simulation, how could I include the potential force in the simulation? I tired us the Pair_style hybrid gran/hertz/history lj/cut 2.5. But I get an error message” pair hybrid sub-style is not used”. Can someone help me out? thanks in advance

I typically use the fix_nve integration (only updates position and linear velocity) for my granular simulations as this gives a good approximation of blocky (angular) material behaviour. I am wondering if the sjkr cohesion model can be used with this integrator or do I need to use fix_nve_sphere to get cohesion?

In the mean time, I am making a little test model.

Thank you,

Kirk

Hi,

playing around with the dump image command I came over a restiveness. I inserted some atoms in a lattice with create_atoms, and changed diameter to 0.2 by set command. Computes and dump local/custom are working like expected. The command dump image ignores diameter and uses 1.0, after dump_modify adiam it works as well. Is it because of using create_atom?

Edit:

Dear guys:

I am new to this forum, and I would like to seek some help in the compilation of LIGGGHTS

When I compiled LIGGGHTS using "make openmpi", I encounter the following error messages:

Good morning,

I would like to make a model using the fix mesh/surface/stress/servo command. I was wondering if someone would be willing to share a little example simulation that includes this command?

Thank you in advance,\

Kirk Fraser

Hi all,

I want to simulate a belt conveyor with ribs on the surface. (stl attached)
For a flat belt i would usually use the surface_vel command to specify the imported mesh as conveyor belt.
The Problem about this command is that there is no motion of the ribs. Think this behaviour is expected.

I am trying to use the insert/rate/region command to create a cylinder filled with particles. I have not been able to figure out what role the nparticles keyword plays in determining the number of particles added. I thought that the total number would be limited to "nparticles", but when I run the simulation new particles keep being added after reaching "nparticles". How do I create a region with a fixed number of particles? The code is below. Thanks in advance for your help.

I want to add a force on all atoms in region and the force is related to the coordination of the atoms? How should I specify the force variable? Thanks in advance.