Patent ID: 7634948

Claim:
Process for dynamic measurement of the axial deformation of a rotating hollow shaft comprising the steps of: rotating a hollow shaft having a glass fiber segment of a fiber optic sensor securely attached to a section of the inside wall of the hollow shaft so as to extend in axial alignment with the hollow shaft, injecting a light signal produced by a light source into the glass fiber segment while the hollow shaft is rotating, detecting the light signal after it passes through the glass fiber segment by a detector, and ascertaining axial deformation of the segment of the inside wall of the hollow shaft due rotation thereof by determining axial deformation of the glass fiber segment over a given period of time from a change of at least one parameter of the light signal when the light signal passes through the glass fiber segment; wherein the time behavior of the ascertained axial deformation is evaluated to detect vibrations of at least one of marine engine and cavitation noise transmitted into the shaft.