LIGGGHTS® - User Forum

Hi all,

I have been scratching my head over this one today - my simulation works fine unless I try to dump the per-particle forces with compute pair/gran/local - then it runs for a while, but crashes with:

2374000 1123 6.1525987
[comp-l06:09946] *** Process received signal ***
[comp-l06:09946] Signal: Segmentation fault (11)
[comp-l06:09946] Signal code: Address not mapped (1)
[comp-l06:09946] Failing at address: (nil)
[comp-l06:09946] [ 0] /lib/libpthread.so.0(+0xf8f0) [0x7f19103438f0]

Hi all,

I minor but potentially useful feature request here - would it be possible to add a simple binary flag to the compute pair/gran/local that shows if an interaction is periodic? For contact force chain and similar visualisation this would make it easier to avoid connecting points at opposite sides of a simulation domain etc.

Regards, Mark

Hi Christoph,
I found that LIGGGHTS can not dump stresses on the CAD cylindrical wall properly when the ratio of the diameter of beads to the diameter of cylinder is bigger than 0.02; however, below this ratio, the stress profile is good. But, using this low ratio is computationally expensive. Is there another way to do so?

Thanks,
Ram

Hi,
Is there a way in LIGGGHTS to make granular chain? For example, to glue some granular particles together to make a chain.
Thanks,
Ram

Hi, I tred to install liggghts for the first time. (new to Linux as well).

After typing 'make fedora' in /src got a whole bunches of can't find files. I looked into the src directory, and they are all there.

make[1]: *** [memory.d]Error 1

memory.cpp:14:17: fatal error: mpi.h: No such file or directory
compilation terminated.then it leaves the directory
make[1] Leaving director ' /home/.../liggghts_1p4p3/src/Obj_fedora'
make: ***[fedors] Error 2.

Not sure how to proceed from here. Any help is appreciated

Hi

I am trying to develop a new version of fix_pour by combining the "regionExempts" function of pour/dev with pour. I have created a new pour called pour/exempt and copied accross all the relavent bits of code. I have also made the necessary links to these other files as well: mech_param_gran.cpp, region_block.h (and cylinder), fix_gravity.h, pair_gran.cpp and style_fix.cpp.

Hi all,

I am using compute pair/gran/local and the corresponding dump to look at the particle-particle contact data (and heat flow), but also need to look at particle-wall interactions. As far as I can see, these are not included in these computes/dumps?

I think this would be a very useful addition - I guess it would require assigning each wall an ID etc. In particular I need to identify particles in contact with the wall, and sum their heat fluxes etc.

Dear friends,
Could some body please let me know how can I apply rotation and translation (at the same time) to a moving mesh imported from a stl file. Any response will be truly appreciated.
Regards,
Carlos

Hi all,

I'm trying to set up a sim with a region of fixed temperature particles at the top and bottom, and particles that have variable temperature in between. The docs suggest I do not include adiabatic particles in the heat/gran fix. So I've set up a lattice of (4200) particles and defined regions as:

region upper block INF INF INF INF ${upper_limit} INF units box
region lower block INF INF INF INF INF ${lower_limit} units box
region middle union 2 upper lower side out

group thermal_group region middle
3000 atoms in group thermal_group

Hi everybody,
I would like to start the shear test using LIGGGHTS.
Could you help me in doing it.
I was using velocity command for the control of temperature. So far no success. I came to know about the shear test from the following message.
Many thanks in advance.
Samantaray

Tue, 11/30/2010 - 17:18 — tshan

Dear all,

I have already done some triaxial tests and simple shear tests, but I want to know the contact normal among the particles and then realise them in paraview to further generate the force-chain.