Malleable Strength

How much is too much? One of the very valuable characteristics of steel is that though it is very strong, it can bend. Modern skyscrapers resist high winds and earthquakes because the structure will flex. But invisible changes happen deep inside the steel and stay there when the bending stops. It's called metal fatigue. Some of the highest technology in the field of metallurgy is attempting to detect and measure these changes. This is crucial knowledge to obtain because the steel will bend and hold through many cycles and then at some point of service, while being utilized exactly as many times before, the part will fail. Sometimes the failure will be a crack and thus there is a warning. Other times the failure is a catastrophic break. If the part is supporting life or property, loss of some sort may occur. Once metal has been bent, one is always in doubt about its dependability. But depend on it we must. How much is too much? I hope we don't have to find out.