Embeddable polarimetric fiber optic sensor and method for monitoring of structures

Abstract

The present invention provides the capability of ascertaining, through a quick and simple measurement, locations on a structure that may have experienced damage that could result in reduced structure lifetime, strength, or reliability. The sensing element is a connectorized section of polarization maintaining ('PM') optical fiber, where a length of PM fiber represents a fully distributed sensor array. Stress-induced changes to the sensor are measured through white-light Polarimetric interferometry. The output of the measurement is a data array representing the stress concentration magnitude at an array of locations along the length of the sensor. In an application, the knowledge of the optical fiber position on the structure, coupled with the measurement of stress locations along the fiber length, allows the user to determine locations on the structure with large stress concentrations. These locations may signify structural damage. This knowledge would allow the user to employ a more sophisticated system, albeit a larger and slower one, to fully characterize and evaluate that area of potential damage and take appropriate action.