Implementing fiber optic sensors to monitor humidity and moisture

Kunzler, Wesley; Calvert, Sean G.; Laylor, Marty

doi:10.1117/12.542818

Cited by 6 publications

(4 citation statements)

References 1 publication

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“…Swelling of the polymer due to absorption of moisture induced a longitudinal strain in the FBG, thus shifting the wavelength and signaling the level of humidity. The sensor had a linear response between 0 and 100% humidity with a response time limited by the swelling rate of the polymer [5].…”

Section: Fiber Optic Water Sensorsmentioning

confidence: 99%

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A fiber Bragg grating sensor for detection of liquid water in concrete structures

Ho¹,

Ren²,

Li³

et al. 2013

Smart Mater. Struct.

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Concrete structures rely greatly on the integrity of their supporting rebars to remain serviceable for their intended purposes. Unfortunately, rebars are vulnerable to corrosion due to the ingress of water from the environment, which often also carries a multitude of ionic particles that encourage corrosion. Liquid phase water may enter the structure through cracks that may not be obvious to human observation. Thus, a fiber Bragg grating sensor was designed that is able to detect (i.e. ‘on–off’) the presence of liquid water in order to provide an early warning signal for the ingress of water. Two tests were conducted to verify the functionality of the sensor: the first experiment tested the repeatability of the sensor to cyclic input of various volumes of water, and the second tested the sensor’s response to flooding conditions. The sensor showed a good repeatability, with fast response times (<10 min to reach a level guaranteeing the presence of water) and a recovery time of 11–15 h, depending on the input volume. The flooding test showed similar performance and viability of the sensor during flooding conditions.

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Section: Fiber Optic Water Sensorsmentioning

confidence: 99%

“…Some examples of such sensors include mechanical hygrometers, animal hairs, psychrometers, etc [3,6]. These sensors have had broad applications across agriculture, weather prediction, medicine, etc [5].…”

Section: Introductionmentioning

confidence: 99%

A fiber Bragg grating sensor for detection of liquid water in concrete structures

Ho¹,

Ren²,

Li³

et al. 2013

Smart Mater. Struct.

View full text Add to dashboard Cite

show abstract

“…A number of sensors have been developed to monitor the presence of water either in gas or liquid phases, and most of them are designed to measure the relative air humidity [3][4][5][6][7][8][9]. Conventional water sensors are mostly electronically based.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the rapid development of fiber optics provides an opportunity to develop fiber Bragg gating (FBG)-based sensor. Typical FBG-based sensors, which have previously been used to evaluate relative air humidity, can be fabricated by an FBG coated with a water-swellable polymer [6][7][8][9]. The wavelength of the wave propagating in the FBG will change corresponding to the swelling of the polymer induced by the absorption of moisture.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of water seepage monitoring in concrete with embedded smart aggregates by P-wave travel time measurement

Zou

Liu

Huang

et al. 2014

Smart Mater. Struct.

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Water seepage in concrete threatens the safety of marine constructions and reduces the durability of concrete structures. This note presents a smart aggregate-based monitoring method to monitor the travel time evolution of a harmonic stress wave during the water infiltrating process in concrete structures. An experimental investigation, in which two plain concrete columns were examined under different water infiltration cases, verified the validity of the proposed monitoring method. The test results show that the travel time of the harmonic stress wave is sensitive to the development of water seepage in concrete and decreases with increasing water seepage depth. The proposed active monitoring method provides an innovative approach to monitor water seepage in concrete structures.

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