Dear all,
I would like to simulate a macroscopic object in contact with a granular system,
sort of a rotating ratchet.
I have the mesh and can insert it in my simulated granular system, but I would
like to have it "fixed" in space, and rotating around one (fixed) axis.
Basically I would need a mesh/gran/1dof fix :-)
I have solved translations by applying a strong spring that does not allow
my mesh to move away. However, it does still rotate with 3 dof, and I would
like to have just one.
Any suggestion/ideas/comments?
Thank you,
Alessandro
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tdl | Tue, 08/14/2012 - 14:25
(BUMP)
(BUMP)
jtholle | Tue, 08/14/2012 - 20:01
move/mesh command
Maybe I don't understand your application, but can you just do a
fix move all move/mesh mesh cad1 rotate origin 0. 0. 0. axis 0. 0. 1. period 0.05
or something similar to rotate the mesh around a single axis.
This should allow the mesh to rotate around the z axis without any movement in the other directions.
Hope this helps,
Jeromy
tdl | Wed, 08/15/2012 - 16:09
Dear Jeromy, thanks for you
Dear Jeromy,
thanks for you comment.
Unfortunately I would like to simulate the "free" rotation (only around the fixed axis of rotation) of the mesh under the effect of the granular system.
The fix you mentioned instead induces an specifically defined rotation on the mesh. This could be useful to drive the system (for example, in simulations of mills) but is not what I would like to study.
Thank you anyway!
richti83 | Thu, 08/16/2012 - 14:43
Hi Alessandro, sounds to me
Hi Alessandro,
sounds to me like a good use-case for a coupled-dem-mbd simulation.
Are you familar with modelica ?
Other idea: you could get the moment on the mesh by stressanalysis and calculate new Omega every Iteration in a variable omega, than use rotate/variable to set the new angular velocity to v_omega. (never tried, prefix v_ to tell liggghts to calculate this var every step)
I made a little planar pendulum before I did this: http://web678.public1.linz.at/media/DEM/featured/wheelloader_DEM_MBD_LIG...
where I have had the same "problem". (we solved this by a little modelica-script outside of liggghts)
DEM-MBD Pendulum: http://www.richtisoft.de/transfer/video05.avi