LIGGGHTS® - User Forum

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:

Dear LIGGGHTS team,
I'd like to do a simulation which hybrid the granular and sph atom styles
some granular particles in the bottom of a container, then add some water(sph model) on these particles, then close the lid.
My code is as follows

#### initialization #
#variables
variable mass universe 0.001 #0.001
variable h universe 0.012 #0.012

variable lat equal $h/1.2 # = 0.01
variable lathalf equal ${lat}*0.5
variable skin equal $h*0.25
variable wallpos equal ${lathalf}
variable eta equal 0.01*$h*$h

Hello Everyone,

I am trying to find out the segregation intensity defined by Danckwerts http://link.springer.com/article/10.1007/BF03184936
The key idea is to divide the 3d-region into grids and calculate the number of particles in each cells. Is there a function pre-existing in liggghts or paraview that could aid in the implementation?

Siddharth