LIGGGHTS® - User Forum

Hi,

I'm trying to use a compute in a variable. I know that a compute doesnt mean that it is calculated, so I want to use fix ave/time for calculation.


compute A thirdgroup reduce max y
fix currentstatus all ave/time 100 1 100 c_A
run 1
variable B equal c_A
print '$B'


this doesnt work. Just when I use the thermo_style it works:

compute A thirdgroup reduce max y
thermo_style custom step atoms ke vol dt etotal c_A
run 1
variable B equal c_A
print '$B'


Hi,

I am developing a numerical ring shear test. For that I am using a rectangular 3D box with a size of 8e-2 * 8e-2 * 4.4e-2 m. I fill this box with ~25.000 particles with sizes of 9.2e-4 to 16.4e-4 m. After settling under gravity I want to compress the probe with a servo wall and a target value of -5e6 Pa (in z direction).

My particles have follwing parameters, following Aigner et al., 2013 "Determing the coefficient of friction by shear tester simulation":

I am trying to install LIGGGHTS 3.1.0 but it throws the error:
multisphere_parallel.h: No such file or directory

Checked with the LIGGGHTS GitHub repo as well, but I found that no such file is there in the repo.
Kindly help

Hi all,

Can anyone help me in working with assigning external electric field ?
I could not find much information about this part, like how am I supposed to change the source code in setting the E-field direction?

Thank you.

Dear all,
I used to calculate lift force by Archimedes and the value is 0 0 5.13126e06(it equals to volume * density *9.81 ). The value is only at positive z direction. But today I update the CFDEM software. and i found the lift force calculated by Archimedes force model is not the same, x y z three direction all have values. Who can answer my confusing?

Thanks
xiaobaishu

Dear users,
Do anybody know how to use voronoi package? I compiled it in my liggghts, but it didn't work. I want to calculate the voidage. or is there any other command to calculate void ratio?

Hi

I was going through some tutorial in the website and found wear through a chute. Though it shows colors changing with time due to wear in the surface of the metal, the unit of wear is not there.

How much time it takes to develop a wear on a surface. Is it material dependent/time dependent/impact velocity dependent?

How do i understand the estimate of time of simulation to develop a wear on a surface. Any info regarding these will be helpful.

Thanks in advance.

Saprativ

Hi,

I want to insert cylinderical particles in my system and I've read all the discussions in the forum about multispheres. unfortunately they didn'e help me.
I'm not familiar about making molecules clumps and using fix rigid. can anyone help me about generating and inserting non-sphere particles step by step?
an example script could be very helpful.

BTW I have STL of my particle, but I'm not sure if it could be helpful!

Thanks,
SHG

Hello,
unfortunatly, I didn't find a good answer for this problem.
Is it possible to assign a temperature, when an particle is created.
Im trying to simulate the temperatur transition of two diffenent particletypes, while they are mixed. Therefore, the "fix heat/gran" command is not usable.
I know, that it ist possible to assign a velocity, but I wasn't lucky, searching for it.
It might be done with the set "region xy temperature T" command. But thats not a satisfactory solution.

I hope someone can help me.

Thanks
RobertG

Hi,

I am trying to do a problem similar to example in.mesh_tet. While executing in liggghts, I repeatedly get the error message "Set command with no atoms existing". While running the in.mesh_tet example there was no problem like this.

I am attaching my command file, model and log file.

Can anyone please help me with this problem?