Force on mesh/surface

Submitted by Weijing on Wed, 05/24/2017 - 10:26

Hi there

Is it possible to calculate the force acting on the mesh/surface?

In my simulation, I use the fix top all mesh/surface/stress/servo file bottom.stl type 1 scale 0.03 move -0.015 -0.015 0.1 com 0. 0. 0. ctrlPV force axis 0. 0. -1. target_val 0.0003467 vel_max 5e3 mode auto ratio 0.01 to cap the particles. how can I manage to know the force on the mesh? because I suppose this command will set the wall compress the particles by 0.0003467N.

Thanks
Weijing

Forums:

mschramm | Wed, 05/24/2017 - 15:41

Hello,
You will want to use f_top.
For example to get the forces
variable f_x equal f_top[1]
variable f_y equal f_top[2]
variable f_z equal f_top[3]
and if you want the z axis displacement
variable disp_z equal f_top[9]

Tannaz | Wed, 07/03/2024 - 03:02

Hi,
I am using LIGGGHTS-WITH-BONDS for simulating a uniaxial compression test, and I need to plot a stress/strain curve. When I use 'variable disp_z equal f_top[9]' to obtain the mesh displacement at each timestep, I encounter the following error: ERROR: Mismatched fix in variable formula. Do you know the reason for this?

Regards,
Tannaz

Weijing | Thu, 05/25/2017 - 02:24

Thanks for the reply. May I ask a further question?

I have tried those command to access the force on the mesh/surface. however, the force I obtained by those command is completely different from the target force I use the fix mech/surface/stress/servo command compress the particle packing. In my simulation, the packing is vibrated in Z axis by a bottom plane.

Thanks
Weijing