Dynamic fiber Bragg grating sensing method. (27th January 2016)

• Record Type: Journal Article
• Authors: Ho, Siu Chun Michael; Ren, Liang; Li, Hongnan; Song, Gangbing
• Is Part Of: Smart materials and structures. Volume 25:Number 2(2016:Feb.)
• Publication Date: 2016-01-27
• Subjects: fiber Bragg grating -- interrogation -- fiber optic sensor -- structural health monitoring -- vibrations; Smart materials -- Periodicals; Strucural design -- Periodicals; 620.11
• DOI: 10.1088/0964-1726/25/2/025028
• Languages: English
• ISSNs: 0964-1726

Abstract

Abstract: The measurement of high frequency vibrations is important in many scientific and engineering problems. This paper presents a novel, cost effective method using fiber optic fiber Bragg gratings (FBGs) for the measurement of high frequency vibrations. The method uses wavelength matched FBG sensors, with the first sensor acting as a transmission filter and the second sensor acting as the sensing portion. Energy fluctuations in the reflection spectrum of the second FBG due to wavelength mismatch between the sensors are captured by a photodiode. An in-depth analysis of the optical circuit is provided to predict the behavior of the method as well as identify ways to optimize the method. Simple demonstrations of the method were performed with the FBG sensing system installed on a piezoelectric transducer and on a wind turbine blade. Vibrations were measured with sampling frequencies up to 1 MHz for demonstrative purposes. The sensing method can be multiplexed for use with multiple sensors, and with care, can be retrofitted to work with FBG sensors already installed on a structure.