[lammps-users] command for shear loading


Which command should I use for the application of shear loading? fix deform or velocity?

Thanks in advance.


If you have a periodic system, fix deform. If you have a fully non-periodic system in
then you need to set a shear velocity on portions of the system at the top
and bottom.


Got it. Thanks.

Please discard the previous message.

Hi Steve,

For tensile loading, I use the velocity using the following command. For example, for the first line I want to add 0.1 Ang/ps in x direction.
velocity up set 0.1 0.0 0.00 units box
velocity low set -0.1 0.0 0.00 units box
velocity mobile ramp vx -0.1 0.1 x -40.92.0 39.5432 sum yes

But in case of shear, will it remain in the same way?

Thank you.

Only if you turn off forces on the boundary atoms, e.g. viz fix setforce.
Otherwise their velocity will change over time.

I suggest you visualize your system. Then you can verify it is doing
what you expect. There is no substitute for trying things out and verifying
they are correct.