Is it possible that sound waves can weaken structures or even eventually cause them to fail? Well it depends on the power and the harmonic but yes this is possible? But if this is so why do we use sound waves to see inside structures to test if they are strong or not? Arent we causing their premature failure? We use ultrasound to look at the insides of dams to see if they are still safe after many years right?

Interesting you bring this up, as when I read about this theory I thought, well that does not sound right to me really. Especially considering that inside larger structures like let's say Hoover Dam there is concrete which does not dry or harden for 50 years or more and there might be space cavities in side. Some of the concrete inside of Hoover Dam is thought to be still not completely dried; hard to believe indeed.

But even so would ultrasound testing of the structure negatively affect its structural integrity somehow? Well I guess in some ways it makes sense as everything is connected to everything else and any sound waves would affect ionic bonding; either in a negative or positive way, even if it was so small it was hard to measure.

So, this brings up another point, can we strengthen concrete while testing it? For instance the Big Dig? Can we strengthen the structure with waves of sound? Or? Perhaps I should re-examine this thought. As it could lead to so many more applications for Military, Construction, Demolition, Manufacturing, Public Safety, Volcanic Super Plume pressure relief, directed sound to help in mining or even cutting rocks. Interesting. This is an interesting topic. Perhaps this should be studied further. Interesting topic indeed.