5 February 1990 Interferometric Measurement And Calibration Of Dc Strain Of A Fiber Optic Embedded Graphite Epoxy Composite Panel
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Abstract
Measurements of DC strain produced by transverse deflection of a fiber optic embedded graphite/ bismaleimide composite panel in cantilever geometry were made using a Mach Zehnder interferometer and active homodyne demodulation technique. The measured strain ranged from an average longitudinal strain of 2.0 x 10-4 to 6.6 x 10-7, corresponding to a maximum transverse deflection of 0.3 inches (3%) and a minimum transverse deflection of 0.001 inches respectively. We find that the strain optic coefficient of the embedded fiber ranges from 30% to 40% less than the value for uniaxial strain. In addition, these measurements reveal hysteresis and or creep during the loading and unloading cycle of the composite. Experiments were performed to determine sources of DC drift, and the main sources of DC drift identified. Calibration of the results is discussed as well as future modifications that will permit four orders of magnitude increase in tracking range, greatly improved interferometer stability, and elimination of the effects of piezoelectric hysteresis on the measurement of strain.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Keith H. Wanser, Keith H. Wanser, Tom D. Wang, Tom D. Wang, } "Interferometric Measurement And Calibration Of Dc Strain Of A Fiber Optic Embedded Graphite Epoxy Composite Panel", Proc. SPIE 1170, Fiber Optic Smart Structures and Skins II, (5 February 1990); doi: 10.1117/12.963116; https://doi.org/10.1117/12.963116
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