Hi and thank you in advance. I want to understand how do fractures/breaks/fatigues occur in general. I remember a proverb saying that when a farmer breaks a rock after 100 hits using his axe, it is not the 100th hit that breaks the rock, but it is all of the 100 hits. How material break? what happens when you hit a metal with something and it doesn't break? where does the energy go? does every hit means a degradation in the structure (although not visible)? For example, if I gently hit my tooth with a spoon, do I still impact the structure of my tooth (although my tooth doesn't break?) I hope you understand my question. Thank you and best regards.