Yashendra In Workbench, use File, Archive to save a .wbpz file and attach that to your reply, but use Clear Generated Data on the Mesh before you save the file to reduce file size.
You need to mesh with at least 4 elements through the wall thickness and it is better if you have more.
You can have a plate impact the structure at those three constant velocities, it will just create some noise in the solution, however, since you are plotting energy, that will average out over the structure.
Why do you need 3 velocities? It might not be possible to finish this project in 2 days.