This idea has more to do with basic Research.

Imagine a lattice of springs and masses. Let's do this together. Draw a cartesian axis xy on a desk. First, place some ball masses on a table, forming a grid with masses equally distant to each other. Put like 5x5=25 masses, 5 rows, 5 columns. Connect the masses by springs, only in the x and y direction. Don't cross connect springs in the diagonal. 

Now, in the south there are 5 masses. Hook up each one of them to a motor that produces vibrations on the masses. It is important that you can control the frequency of these vibrations. Now, on the 5 masses of the right, hook up a magnet that moves inside a coil, one magnet and coil for each mass. The south masses will transfer energy into the lattice while the right ones will remove energy from the lattice. Fix the left and north side, with springs to wooden fixed supports. 

The goal is to find a way, somehow, to use this arrangement to store as much energy as possible inside the lattice, in the modes of vibration. It is also important to find a way to release this energy into the right masses, whenever you want.

First, can you turn a movement that is in y-direction to a motion that is in the x-direction?

Then explore the modes of vibration, trying to keep the vibrations inside the lattice. 

I don't know if this is possible, honestly.