Skip to main content. Search results. Reflective Tilted Fiber Bragg Grating TFBG sensors have intriguing sensing capabilities due to the resonance-peaks present in their transmitted spectrum. Previous works measured the external refractive index ERI in which the TFBG sensor is placed, by considering the wavelengths or the envelope of the cladding-modes resonances.
Gopakumar Sethuraman , Virginia Commonwealth University. In this work, reagentless fiber optic-based chemical sensors for water quality testing were fabricated by coating fiber Bragg gratings with the glassy polymer cellulose acetate. With this polymeric matrix capable of localizing or concentrating chemical constituents within its structure, immersion of the coated grating in various chemical solutions causes the rigid polymer to expand and mechanically strain the glass fiber. The corresponding changes in the periodicity of the grating subsequently result in altered Bragg-reflected responses. A high-resolution tunable fiber ring laser interrogator is used to obtain room temperature reflectance spectrograms from two fiber gratings at nm and nm wavelengths. Rapidly swept measurements of the full spectral shapes yield real-time chemical detection and identification. Electrical and Computer Engineering Commons.
The grouted connection is a well-known technology in the offshore sector and notably in the oil and gas sector for the foundations. It consists in the high performance grout-filled space enabling the connection between two concentric steel tubulars. This technique has also been selected in the offshore wind sector for connecting the wind turbine to its foundation.
These profiles were repeated for a wide range of temperatures from to , in steps of. Two different types of instrumentation methods have been tested, spot welding and epoxy bonding, in two different materials, steel and carbon fiber reinforced polymer CFRP. We discuss the results for each type of sensor and instrumentation method by analyzing the linearity of the Bragg wavelength with RH and temperature. Optical fiber sensors are one of the most suitable options for aircraft structural health monitoring SHM systems due to the advantages they offer: immunity to electromagnetic noise, with the consequent increase of safety and a better protection against loss of information; little weight compared with traditional monitoring systems, leading to a reduction of fuel consumption; and wide working temperature ranges [ 1 ]. At present, the application areas for fiber sensors are increasing; they can be used for corrosion monitoring in metallic components, carbon fiber reinforced polymers CFRP , aircraft components health monitoring, sensing pressure, temperature, or microelectromechanical systems MEMS accelerometers [ 2 ], impact detection, vibration and strain measurement, or static strain temperatures.