Dear all
I am using the following command to dump the particle information. I am interested total force acting on the particle including weight of particle and all interaction forces. For this I am using the following command.
------------------
dump dmp all custom/vtk ${nstep} post/two_wall/particle_*.vtk id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
----------------
The above command dumps the value of forces as zero for most of the time. I am NOT sure about what LIGGGHTS is dumping as fx fy fz
1. I want to know what is the actual meaning of fx fy fz
2. How can I get actual forces on each particle including weight of particle and all interaction forces
mschramm | Mon, 02/10/2020 - 16:17
input script
Hello,
fx, fy, and fz are the force that are acting on a sphere.
Weight you would have to calculate using the fz calculation.
What simulation are you running? Is it one of the tutorial simulations?
Rahul Kumar | Tue, 02/11/2020 - 06:34
What simulation are you running?
What simulation are you running?
1. yes, I am running the chute_wear tutorial
1. How do I calculate total force including weight
mschramm | Wed, 02/19/2020 - 16:06
total force
Hello,
So if you have a particle in free fall and not interacting with anything, you will see the fz component (assuming you have gravity acting in the negative z direction) equal -9.81*${particleMass}.
As soon as the particle starts to interact with things, this will not be the case as the force components only store total forces. As an example, if you have a sphere laying on the ground not moving,
the contact force between the particle and the surface will equal the force caused by gravity but in the opposite direction. Thus, fz will have a value of 0.
What is your end goal? What are you trying to simulate? I think we need more information in order to properly help find what your after because I do not think you want the answer.
ForceTotal = fx+fy+fz
ForceMag = sqrt(fx*fx+fy*fy+fz*fz)