PPRuNe Forums - View Single Post - EC225 crash near Bergen, Norway April 2016
Old 19th May 2017, 10:05
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G0ULI
 
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Concentric

This does appear to be a plausible mechanism to explain the crack propagation in the gears. It cannot be the sole reason because a crack has to be initiated by some other event or process first, but once that opening or pit is created it would seem that eventual failure is inevitable. Every compression cycle would be the equivalent of driving an incompressible hydraulic wedge deeper into the material. As the process continues the hardness of the surface layer would assist in driving the crack propagation deeper into the softer underlying material.
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