LIGGGHTS® - User Forum

Hi everybody,

Hi,

Hi,

Has anyone experienced problems with simulations stopping in what appears to be random points, without returning any errors? To make things more confusing, the point it stops at is not repeatable. All I am using is a modified version of the conveyor tutorial fine included with LIGGGHTS. I am currently using 3.7.0, but had a similar problem with 3.3.0. The issue with 3.3.0 seemed to appear just after upgrading to Ubuntu 16.04, but the current 3.7.0 has been recompiled after upgrading.

Hi,
I have some questions regarding the implementation of the “cohesion_model_easo_capillary_viscous.h” (or for that matter washino) which I would really appreciate your reply to help me understand the algorithm and to properly apply the code. My main questions are with regards to the criteria to evaluate the three possible cases of no-bridge, active, breakage of the liquid bridge force.
Thank you for your time and consideration.
Ali

Dear all,

Dear all,

I am a little confused about the usage of the variable type of f_a and ${a}. To give an example, when I use "fix a all mesh/serface/stress/servo ...", I want to obtain the displacement of the servo wall, thus I use "variable loct euqal f_a[9]-0.1" where 0.1 is the original of the servo stl wall. When I want to applied this variable in another command (e.g. fix b all mesh/surface/stress ... move 0. 0. ${loct}), the ERROR message shows: invalid fix ID in variable formula.

When trying to create bonds in "LIGGGHTS-WITH-BONDS" , I get the following error:

creating bond btw atoms 726 and 1741 (i has now 12 bonds) at step 1001
creating bond btw atoms 726 and 1743 (i has now 13 bonds) at step 1001
ERROR on proc 0: New bond exceeded bonds per atom in fix bond/create (../fix_bond_create_gran.cpp:485)

Dear all,

I am using command "read_restart" to restart my simulation and used the same servo wall command as the original code which is applied to create the restart file (shown below).

"fix topwall all mesh/surface/stress/servo file meshes/topwall.stl type 2 com 0. 0. 0.1 ctrlPV force axis 0. 0. -1 target_val 300 vel_max 0.03 kp 1"

Dear All,

I would like to create a gaussian or log-normal particle size distribution, I mean for the particles radii. Unfortunately, I cannot find anything in the documentation, even though someone implemented a "radius gaussian number" in the "in.liggghts_init" (input command file for DEM). For example:

Dear all,

I am doing a triaxial compression test using LIGGGHTS. First, I applied six servo controlled wall using command: fix mesh/surface/stress/servo to execute a confining pressure on a cube soil specimen. After this process, I want to execute a constant velocity on the walls instead of a target force on the servo walls. This means I may need to change the servo controlled wall to velocity controlled wall.