Distributed fiber optic sensors for monitoring pressure and stiffness changes in out-of-round pipes

Distributed fiber optic sensors have been shown to be promising when used to monitor the structural health of pipes. The body of work thus far has only considered pipes whose cross sections are assumed to remain circular under load. In some applications, the cross section of the pipe has been known to deform when loaded. Subsequent loading on a deformed pipe then generates additional stresses that may have been unaccounted for when designing the pipe. This paper addresses the effects of the initial non-circular cross section of a pipe under internal pressure and its detection with a distributed fiber optic sensor based on Brillouin Optical Time Domain Analysis. This ability of the Brillouin Optical Time Domain Analysis sensor to detect local stiffness irregularities on an out-of-round pipe subjected to internal pressures is also demonstrated. Copyright © 2015 John Wiley & Sons, Ltd.