Abstract
A fiber Bragg grating (FBG) sensor integrated with an epoxy diaphragm was developed for the measurement of pressure and water level. The bending strain of a circular diaphragm induced by uniform pressure was transferred to the FBG sensor. The response of the FBG sensor to the pressure was observed in terms of the Bragg wavelength shift which is linearly proportional to the strain. The effect of epoxy diaphragm thickness on the sensitivity and accuracy was investigated. The experimental results show that the sensitivity of FBG/epoxy diaphragm pressure sensor is decreasing with the increase of the diaphragm thickness. The sensitivities of the FBG pressure sensors with diaphragm thicknesses of 0.5 mm, 0.7 mm, and 1.0 mm were 175.5 pm/kPa, 89.5 pm/kPa, and 43.7 pm/kPa, respectively. The pressure measured by the proposed FBG sensor was compared with theoretical prediction and a close agreement was observed.
Highlights
Pressure is one of the most important parameters for structural safety monitoring in engineering applications
Of fiber Bragg grating (FBG) sensors integrated with metal and by the theoretical prediction with excellent correlation
It shows that the pressure sensitivity 175.5 pm/kPa of the proposed FBG sensor integrated with epoxy diaphragm is better than that of metal [33]
Summary
Pressure is one of the most important parameters for structural safety monitoring in engineering applications. Development of accurate and effective sensors for the measurement of liquid level or pipe pressure are essential in a variety of industries, such as the oil [1] and chemical [2] industries. Various sensing methodologies based on mechanical, electrical and optical techniques have been proposed for the evaluation of pressure and liquid level. Traditional electrical or mechanical pressure sensors have limited capabilities in harsh environments such as series electromagnetic interference [3], high temperature and pressure [4,5], dangerous chemicals, or explosive substances [6]. Singlepoint measurement and incapable of remote transmission and on-line monitoring further restrict the applications of the traditional electrical and mechanical pressure sensors [7]. There are three different types of optical fiber pressure sensors: intensity-based [10]; fiber Bragg grating (FBG)-based [11]; and
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