The explanation given to me was that the shaft would behave like a skipping rope during an overspeed but would normally return to shape after the event.
However the damage would manifest itself as hairline cracks along the shaft midway between the splined ends i.e at the point of maximum whip.
Hence a requirement for a magnaflux NDT inspection.
I suppose that if the overspeed was large enough then it might indeed assume the shape of a banana, but then you wouldn't need an NDT!!!
Last edited by ericferret; 26th Jul 2012 at 16:30.