LIGGGHTS® - User Forum

Hey Guys, I'm using the "lattice" command prior to the "create_atoms" command, and I would really like to know what " lattice constant" in the "scale" keyword denotes. Is it the edge length of a unit cell or is it the diagonal length of the unit cell in 3D ? I want to create different packing structures using fcc, bcc , and so on by making the two particles ( 0.01m dia ) touching each other in every unit cell. Will my lattice constant be same for all styles viz. hcp, fcc, bcc, sc and diamond ?? please help.

regards,
Anand

Hi All,
I'm a new user of LIGGGHTS. I want to make packings of particles and export the surface mesh of them. Is it possible with LIGGGHTS?
If not, do you know how can I create a surface mesh of particles from the output files from simulations?

Thank you :-)

Hi,

Can anyone help me to format the move/mesh viblin command to approximate a linear vibratory actuator?

These actuators can be approximated with a simple 1 DOF model Md2x/dt2 + cdx/dt + kx = Fsin(wt), where m is mass, c is damping and k is spring stiffness. >> Basically simple harmonic motion in one direction.

The axis, amplitude and period parameters are self-explanatory, but I'm not sure how to relate the phase parameters in the function back to the motion of the thing. I assume I need to use second order.

Thanks for your help.

Hi all!

I have been on-off using LIGGGHTS for a few months now, and I have to say I love reading all the new functions and opportunities that come out all the time!

I have recently started a new project in LIGGGHTS that I am a little stuck on how to approach and/or not sure it can be entirely possible!

Hi all,

Why is LIGGGHTS calculating everything using OVERLAP methodology while its not applicable in real problems?
As even soft-sphere model assumes that deformation is taken into account for force models.
Why no deformation and only overlap in LIGGGHTS?
Any specific reason for this?

I apologize if this question is stupid or already answered.

Thank you.

Dear All

Is it possible to scale mesh file (.stl) by different scale factor in x- y- and z- direction?

Regards
Esmaeil

Hello,
this problem bothers me the whole day.
Every time I restart my simulation, I got the same error message:

ERROR: Mesh (id cad2): Mesh elements have been lost / left the domain. Please use 'boundary m m m' or scale/translate/rotate the mesh or change its dynamics (../multi_node_mesh_parallel_I.h:637)

I used every Liggghts-Version since 3.1

I know it is a known problem.
But a while back, it worked well.

first: load restard-file
then: load stl-files
then: run 1
then: move/mesh

Hello guys,

I define a atom variable. Then loop all atoms, do some calculation about the array and get a value of every atom. Finally modify the radius of every atom, as follows:

I'm trying to model some particles flowing over a heated surface. In my lab, I know how much power my heater consumes, and therefore know the wall heat flux.

Is it possible to apply this boundary condition to a wall in LIGGGHTS? I know how to give a wall a certain temperature, but as stated, I don't technically know that. If this is possible, does the wall have to be an imported mesh, or can it be a primitive? I see that I can compute the heat flux of a particle in contact with a wall, so I thought that making this a fixed value would be easy to do.

Hello everybody!

I was wondering if the order of the material properties fix and the contact model in the LIGGGHTS script matters? In the doc it is not written that the material-fix has to be specified before the pair style command, but I wanted to make sure I can change the script like this and the result will be the same: