This paper presents an extrinsic Fabry-Perot interferometer-based optical fiber sensor (EFPI) for measuring three-dimensional (3D) displacements, including interfacial sliding and debonding during delamination. The idea employs three spatially arranged EFPIs as the sensing elements. In our sensor, the three EFPIs are formed by three endfaces of three optical fibers and their corresponding inclined mirrors. Two coincident roof-like metallic structures are used to support the three fibers and the three mirrors, respectively. Our sensor was calibrated and then used to monitor interfacial sliding and debonding between a long square brick of mortar and its support structure (i.e., a steel base plate) during the drying/curing process. This robust and easy-to-manufacture triaxial EFPI-based 3D displacement sensor has great potential in structural health monitoring, the construction industry, oil well monitoring, and geotechnology.


Electrical and Computer Engineering


University of Missouri Research Board
Missouri University of Science and Technology. Materials Research Center


This work was supported in part by University of Missouri Research Board and Materials Research Center at Missouri S & T

Keywords and Phrases

Construction industry; Debonding; Delamination; Interferometers; Mirrors; Oil wells; Optical fibers, 3-D displacement; Displacement sensor; Interfacial sliding; Metallic structures; Sensing elements; Support structures; Three-dimensional displacements; Threedimensional (3-d), Structural health monitoring; Extrinsic Fabry-Perot interferometer

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Article - Journal

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Final Version

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Publication Date

01 Nov 2017