Detection of the onset of damage using an extrinsic Fabry-Perot interferometric strain sensor (EFPI-SS)

12 July 1993

proceedings article
Published by SPIE-Intl Soc Optical Eng

Vol. 1918, 154-165
https://doi.org/10.1117/12.147973

Abstract

The ability of the extrinsic Fabry-Perot interferometric strain sensor (EFPI-SS) to detect the onset of damage in composite laminates was investigated. Composite specimens with EFPI-SS embedded near a local stress concentrator (0.25 in. diameter hole) were subjected to quasi- static and constant amplitude cyclic loading. The test results showed that the particular EFPI- SSs used in this study were inadequate for structural health monitoring purposes. Many sensors did not survive the specimen fabrication process, and the surviving sensors degraded at an applied gross stress of approximately 30 ksi. The degradation seems to be due to the failure of the adhesive bond between the single-mode optical fiber lead and silica glass tube. Nevertheless, the data shows that improved EFPI-SSs can be used to monitor local strain changes in composites during service usage.

Keywords

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