This is not a joke! Material fatigue has been researched for over 100 years.
"The mechanics behind – and inside – this slow fatigue are difficult to study. They’re literally hiding in the cracks. ...
A research group ... has made a breakthrough in understanding how some materials break. By using atomic modeling, the researchers identified the mechanism that causes fatigue cracks to grow: a defect – or dislocation – in the structure that begins near the crack tip, moves away from it, then returns to a slightly different location.
The finding could help engineers better anticipate a material’s behavior and design novel alloys that resist fatigue. ...
A fourth simulation succeeded in propagating the crack after the team realized the defects needed to interact more closely with the crack tip, such that the atomic bonds would break. ..."
A fourth simulation succeeded in propagating the crack after the team realized the defects needed to interact more closely with the crack tip, such that the atomic bonds would break. ..."
From the abstract:
"Structural failures resulting from prolonged low-amplitude loading are particularly problematic. Over the past century a succession of mechanisms have been hypothesized, as experimental validation has remained out of reach. Here we show by atomistic modeling that sustained fatigue crack growth in vacuum requires emitted dislocations to change slip planes prior to their reabsorption into the crack on the opposite side of the loading cycle. ... Our results provide a mechanistic foundation to relate fatigue crack growth tendency to fundamental material properties, e.g. stacking fault energies and elastic moduli, opening the door for improved prognosis and the design of novel fatigue resistance alloys."
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