LIGGGHTS® - User Forum

I want to use the fix move/mesh with the linear/variable style but I don’t know in which way I have dot define the variables for the velocity. Is it an array that has the same number of elements as time steps? Or is it a scalar and I have to change its value every time step. Can you give an short example please.
And a further issue, is it possible to import data form a file, so that I can impose measured motions.

See - http://cfdem.dcs-computing.com/?q=node/920 . I didn't know if my comment would be more pertinent for a user forum or not.

I compile the LIGGGHTS (2013-Jun13) on Cygwin Platform using the make_serial, the message shows “INT64_MAX” undeclared in update.cpp. Can anyone help me out on this issue?

Hi,

What would be the best way to calibrate the simulated particles to behave like a real granular soil and how to demonstrate this?
Is there a way to run some virtual triaxial and shear tests which can be compared to real measurements?
Has somebody done already so and would be willing to share some information?

Cheers
Günter

Hi everyone,

In the simulation, I want to delet the particles which run out of the region. How can I do that? which command Should I use and where I should put the command after creating the particles in the in. file or the end of the file?
thanks in adance.

yyu

Hi all, I wanna simulate brittle material like rock, which means the bonds between particles should start from a bonding model with certain strength(both in normal and shear direction), then after loading (acting external force), the bonds should break and then the particles can move freely so that a collision model should be applied.
Does anyone have similar problem, how you solve it with liggghts, what contact model you used?
really appreciate any reply.

I am studying the LIGGGHTS (lammps-13Jun13) for granular simulation under windows platform but I encountered a number of questions. It is a great appreciation if anyone could give me some clues.

Hello all,

I want to simulate a large number of rigid bodies in a granular simulation. Currently I am using fix rigid, which does not scale very well in parallel. Would I get an appreciable speed up if I use POEMS to handle the rigid bodies? Additionally, I was thinking about using very stiff lj/coul bonds to simulate the rigid bodies, would this increase my speed in parallel?

Thank you!
Zamir

HI all
I see doc but I dont understand what is the particlerate!or how particlerate insert particles?
in one example:
nparticles 1000 particlerate 5000 insert_every 1000
how particlerate can be biger than nparticle?
please help me

thank you

Hallo everyone,

I recently found out that the characteristic impact velocity (used for hookeian contact; described in pair_gran) have a high influence to the outcome of my simulation.

I'm not sure which is the meaning of this impact velocity and how to calculate it, maybe someone is able to explain it to me. Since im simulating an almost steady pebble bed, I assume I should set the impact velocity to zero or near zero. Is this correct?

Kind regards,
Philipp