Based on our successful technology of conductance liquid level sensor, combined with the long-period fiber Bragg
grating sensor technology, a floating optical-electrical (OE) sensor array system is designed aimed at the early
monitoring of oil contamination of offshore marine oil spill and pollution control as well as the safety at sea.
A discrete liquid level sensor based on fiber Bragg grating (FBG) that is suitable for liquid level monitoring is proposed.
FBG (fiber Bragg grating) is embedded in a cantilever beam which is made of carbon fiber composite. And an iron sheet
is bonded with the end of cantilever beam. For the float, a magnet is bonded with the float. When the liquid level rises or
fall, the float will move up or down. The cantilever beam will bend downward or upward, it will induce strain on the
FBG. Therefore, the Bragg wavelength of FBG will shift. An extra reference grating was utilized for temperature
In this paper, a novel pressure sensor based on carbon fiber laminate tube (CFLT) and fiber Bragg grating is proposed.
Theoretical analysis and investigation are conducted. Experiment results indicate that the pressure sensitivity is
138pm/MPa. Pressure sensitivity is improved due to the hollow tube structure compared with solid structure of pressure
sensor that we proposed before.
In this paper, we present a study of detecting the hysteresis effect in strain-stress curve of carbon fiber reinforced
materials by Fiber Bragg Grating technology. By calculating the dissipative energy density contoured by hysteresis
loops, this method can be further applied in detecting the cracks and fatigue of carbon fiber reinforced laminates. In
contrast to the traditional sensors, such FBG sensors have numerous merits, such as small size, immunity to
Electromagnetic Interference and easy installation into the carbon fiber reinforced laminates. This method can also be
extended into monitoring other materials which also exhibit hysteresis effects in their strain-stress curves.
The wavelength demodulation based on a Fiber Fabry-Pérot Tunable Filter (FFP-TF) is a common method for
multiplexing Fiber Bragg Grating (FBG) sensors. But this method cannot be used to detect high frequency signals due to
the limitation by the highest scanning rate that the FFP-TF can achieve. To overcome this disadvantage, in this paper we
present a scheme of cognitive sensors network based on FFP-TF technology. By perceiving the sensing environment,
system can automatically switch into monitoring signals in two modes to obtain better measurement results: multi
measurement points, low frequency (<1 KHz) signal, and few measurement points but high frequency (~50 KHz) signals.
This cognitive sensors network can be realized in current technology and satisfy current most industrial requirements.
A novel liquid-level sensor based on a fiber Bragg grating and carbon fiber composite diaphragm is proposed and demonstrated. The sensing principle and finite element analysis result are described. Because the carbon fiber composite diaphragm's thickness is 0.2 mm and thinner than that of other materials, the sensitivity of the liquid-level sensor is improved. The experimental results show that sensitivity can reach 0.185 nm/m of water height. Based on the high sensitivity and the simple structure of the sensor, this sensor can find applications in the area of liquid level sensing.
A novel liquid-level sensor based on fiber Bragg grating and carbon fiber composite diaphragm is proposed and
demonstrated. The sensing principle and finite element analysis result are described. From the experimental result, this
sensor shows high sensitivity and good repeatability. This sensor can find applications in the area of the liquid level
A temperature-compensated strain-sensing sensor based on fiber Bragg gratings (FBGs) that is suitable for strain
mapping of rock in coal exploring application is demonstrated. FBGs were bonded to carbon fiber laminated composite
(CFLC) and they were arranged in a FBG rosette configuration used to determine the direction and magnitude of the
principal strain, information that is required for strain mapping. An extra reference grating was utilized for temperature
An optical fiber pressure sensor based on fiber Bragg grating (FBG) and metal bellows is presented in this paper. Due to
the lower spring rate of metal bellows, the sensitivity is improved to 48pm/kPa. The relationship between Bragg
wavelength and the applied pressure is derived. Experimental data indicates that there is good linear relation between the
Bragg wavelength shift and the applied pressure. This sensor can be utilized in low pressure measurement.
A novel structure of an optical fiber pressure sensor based on a fiber Bragg grating (FBG) and metal bellows is presented. Due to the novel structure, the sensitivity is improved to 48 pm/kPa. The relationship between Bragg wavelength and the applied pressure is derived. Experimental data indicates that there is a good linear relation between the Bragg wavelength shift and the applied pressure. This sensor can be utilized in low-pressure measurement.
A portable, multi-function WIM sensing system based on Fiber Bragg Grating (FBG) technology is developed to
measure the total weight, the distribution of weight of vehicle in motion (the weights of left front, right front, left rear
and right rear wheels respectively), the distance of wheels axles and distance between left and right wheels. Currently the
speed of vehicle to be tested can be up to 15 mph, the full scope of measurement for this system is 4000 lbs, and the
static sensitivity of sensor head is 20 lbs. This system has been tested respectively at Stevens' campus and Army base.
Compared to other schemes, our method has a number of advantages such as immune to electromagnetic interference,
high repeatability, lightweight, low power consumption, high sensitivity to dynamic strain caused by load of vehicles in
high-speed. The accuracy of whole system can be improved by simulating the mathematical model of sensor heads and
improving the quality of manufacture as well as the calibration condition in the future.