Presentation + Paper
27 March 2019 Discerning localized thermal impulses using an embedded distributed optical fiber sensor network
Brian Jenkins, Peter Joyce, Adam Kong, Charles Nelson
Author Affiliations +
Abstract
An embedded distributed optical fiber sensor (DOFS) based on Rayleigh scattering is used to measure the localized thermal response of a carbon fiber/epoxy composite to directed energy. The thermal impulse from a laser strike is detected while the composite is subjected to cyclic mechanical strain. The ultimate goal is rapid detection of directed energy on the surface of the composite. Prior research demonstrated the use of distributed optical fiber sensors embedded in carbon fiber/epoxy composite structures to rapidly detect temperature changes approaching 1000℃ during a high energy laser strike. However, swept wavelength interferometry used to interrogate a DOFS uses shifts in frequency which can be caused by both changes in temperature and strain. Hence, strain in the composite resulting from mechanical loading is also detected by the embedded sensor and can interfere with rapid detection and measurement of a localized thermal response. Initial tests have demonstrated the simultaneous response of the DOFS to both temperature and strain. A sensing network has been designed to mitigate the response of the sensor to mechanically applied strains, and a simple signal processing technique has been used to cancel the response of the sensor to bending strain while enhancing the thermal response when directed energy is incident on the composite surface. Additional testing indicates that the network and processing technique can also be used to isolate localized impacts on the composite surface from bending strain.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Brian Jenkins, Peter Joyce, Adam Kong, and Charles Nelson "Discerning localized thermal impulses using an embedded distributed optical fiber sensor network", Proc. SPIE 10970, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2019, 109701W (27 March 2019); https://doi.org/10.1117/12.2514386
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KEYWORDS
Sensors

Composites

Temperature metrology

Fiber optics sensors

Optical fibers

Semiconductor lasers

Beam splitters

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