LIGGGHTS® - User Forum

Hi,

I am using 'lmp.extract_compute' in the python. This function could give the right value belong to compute class, but the return value is not ordered by ID. So I checked the library.cpp. I modify the cpp like the function 'data = lmp.gather_atoms(name,type,count)' which could return the value ordered by ID. But I failed. I will appreciate if anyone could help me.

The original cpp shows as follows:

void *lammps_extract_compute(void *ptr, char *id, int style, int type)
{
LAMMPS *lmp = (LAMMPS *) ptr;

Hi everybody,

my problem is the following: if I set the value of 'thermo_modify lost value' to error or warn, I do not get an error or warning message during the execution of the simulation although particles are leaving the simulation domain.

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: