Thank you for your reply.
I've added the following code (it is just a snippet, I do the same for all the faces of the plate), under the solid geometry.
So, I obtain the following signals, on my geometry (aluminum), propagating a 3-cycle sinusoidal signal, nodal force, from the point B (center) to A.
It looks like there are still reflections, but I'm not sure if I am doing it correctly.
Can anyone give me a helping hand?
Thanks a lot