<title>Detecting buckling of filament-wound cylinders with optical fibers</title>

Abstract

This project demonstrated the implementation of embedded optical fibers as sensors for detecting the onset of shell buckling instabilities and compressive failure in composite cylinders. In the present work, five 6-inch diameter cylinders (four filament-wound and one prepreg tape) with integrated optical fiber strain sensors were fabricated and tested in compression. The cylinders were instrumented with an axial strain gage for local strain measurements and a helically-wound 633-nm optical fiber for integrated strain measurement. The integrated strains along the optical fiber path were obtained by using a modified Mach-Zehnder interferometer with feedback electronics controlling PZT's in the reference arm. This distributed sensing technique provides a more reliable and sensitive means of detecting critical strains and the onset of pre-buckling deformations than the conventional local strain gage.

Optimal Design of MPD based fiber optic strain sensors and comparison of power meter and CCD camera based architectures

“…Different types of fiber optic strain sensors were reported using phase, wavelength, and intensity based techniques in the literature. Interferometric sensors such as FabryPerot, Michelson, Mach-Zehnder interferometer [1][2][3], and Fiber Bragg Grating (FBG) sensors [1,4] are examples of phase or wavelength modulated fiber optic sensors. On the other hand, Modal Power Distribution (MPD), Macrobend, and Microbend fiber optic sensors are intensity based sensors [5][6][7].…”

Stability Control of Active Compressed Rods with Shape Memory Polymers

“…Piezo-ceramic actuators have been used for active buckling control [1]. Optical fibers have been used to detect the buckling event in cylindrical shells [2]. Experimental investigation has been carried out on the buckling control of composite beams with embedded Shape Memory Alloys (SMA) [3,4].…”