LIGGGHTS® - User Forum

Hi all,

Dear all,

I am using the servo wall model in version 3.3.

I have a bottom wall and a top wall, the particles are between them.

As the first test, I let the bottom wall far away from the particles, and the condition of it is:

mesh/surface/stress/servo meshes/bottom.stl type 1 stress on com 0 0 0 ctrlPV force axis 0 0 1 target_val 10 vel_max 0.01

because there is no contact between the particles and the bottom_wall, I assume the movement of the bottom wall should be:

Hello all,

I am using compute_stress/atom ke pair. And in Documentation it is mentioned that it doesn't include the contribution of average velocity in kinetic energy contribution. Is there a simple method to include that as well in stress calculation? So right values of stress which will be dumped.

Thanks in advance.

pnkumar

I am learning to use liggghts with tutorial examples.
The example of continuous blending mixer does not go through compiling and always gives an error of:

I am learning to use liggghts with tutorial examples.
The example of continuous blending mixer does not go through compiling and always gives an error of:

I'm a new user and I'm still learning the most helpful commands to run my simulation. In my script I use the ''hertz tangential history rolling_friction cdt'' model. I would like export:
- the collision time
-number of collision
-normal and tangential forces
-energy dissipated

do you know which commands allow me to export these quantities?

kind regards
I hope someone can help me.

Hi All,

Attached are STLs and input script (remove the .txt). I want to know how to run this script so that ins1 runs 20000 time steps then ins2 gets in and runs for 30000 time steps. In short, ins1 will run 50000 time steps and ins2 runs for only the last 30000 time steps.

Thank you for your help.

Hello. I need someone to help me.

I installed and compiled Liggght version 3.3.1 and I have done checking at SRC / version liggghts.h for double check the version.
Then, I have tried many times to run the example. Unfortunately , still it does not work. This is due to my current liggght version is 2.3
8 as stated in terminal.

ERROR :Invalid pair style (/build/buildd/liggghts - 2.3.8/src/force.cpp:181)

What could I do to fix this problem.. Anyone could help me pleased.

Thank You.

Hello!
I am using LIGGGHTS 3.0.7.
I am trying to add a force to the group of particles of a particular type.

Here, what i do:
//create region in which the force should be applied
region field_region block -0.1 0.1 -0.1 +0.1 0 0.1 units box
//define group gg which consists only of particles of type 1
group gg type 1
//trying to apply the force which will try to decrease the speed of the particles
fix mag_field gg addforce 0.0 0.0 +0.3 region field_region

I am trying to extract the total torque on a mesh that rotates about the x axis and I'm having trouble getting the syntax right (LIGGGHTS-3.3). As an example, defining the wall as:
fix mixer all wall/gran model hooke tangential history mesh n_meshes 2 meshes cad1 cad2 store_force yes

can I access the stored forces as shown below?
variable torque atom force_mixer*sqrt(y*y+z*z)

If I try to reduce the x component of the total torque using:
compute c2 all reduce sum v_torque[1]