Now, I'm sure you've all heard of or seen a glass being smashed with resonance- the resonance of the glass is matched to the resonator, which is then 'turned-up' causing the top of the glass to wobble and then smash...
So, I was wondering if you could match the resonance of any material and cuase any material to crumble to pieces. The weapon could find the resonance of the target and intensify it causing it to break. I'm not sure if this would work, probably not, but if it could- the applications would be extraordinary. Any object could be destroyed with a weapon like this. Obviously, you would need a more complex weapon for a structure with multiple materials of different resonance- you'd have to resonate the structure layer by layer...
So, would this work? I highly doubt it myself, otherwise there would already be weapons like this...