Test results of lateral load insensitive FBGs embedded in composites to suppress spectral distortion

Composite constructions are indispensable in current and future society. Fiber Bragg Gratings (FBGs) embedded in composite need to be carefully aligned with the material fibers to reduce inhomogeneous lateral load exerted onto the FBG which occurs due to the inhomogeneous nature of composite materials. Inhomogeneous load causes distortion of the...

1 MHz high-sensitivity FBG sensor system to measure low energy impact in droplet experiment

Fiber Bragg Grating (FBG) sensor is widely used for Structural Health Monitoring (SHM) purpose. For dedicated health monitoring of critical composite parts in aircrafts, maritime constructions, wind turbine blades, etc., high speed measurement can provide vital information to assess impact damage. For example, low-energy droplet impact to wind...

Quantifying the performance of state of the art sensors to measure guided elastic waves

Elastic guided waves are carriers of information of the (change in) condition of plate-like structures like windturbine blades, airplane wings and road surfaces on bridges. To measure these guided waves we do not have to use piezos. Other sensors offer interesting benefits like contactless sensing, embedding, or measuring without electricity....

Miniature FBG-based fluidic flowmeter to measure hot oil and water

In this paper, we present a miniature fluidic flowmeter based on a packaged FBG and laser-heated fibers. The flow rates of water and hydraulic oil were measured by utilizing the proposed flowmeter. The measured results exhibited good sensitivity of 0.339 nm/(m/s) for water and 0.578 nm/(m/s) for oil flow. Experimental results showed that the...

Fatigue crack identification and lifetime prediction for steel bridge deck structures

Fatigue, as the governing degradation mechanism in steel bridge decks, can lead to non-inspectable cracks under the welded intersections of stiffeners to the deck plate. As a result, estimation of the remaining service life and optimization of the maintenance program of steel bridge decks become a great challenge. A comprehensive structural...

Acoustic emission health monitoring of steel bridges

Despite extensive developments in the field of Acoustic Emission (AE) for monitoring fatigue cracks in steel structures, the implementation of AE systems for large-scale bridges is hindered by limitations associated with instrumentation costs and signal processing complexities. This paper sheds light on some of the most important challenges in...

Multidisciplinary health monitoring of a steel bridge deck structure

Fatigue cracks in orthotropic bridge decks are an important cause for the necessary renovation of existing bridges. Parallel utilization of various technologies based on different physical sensing principles can potentially maximize the efficiency of structural health monitoring (SHM) systems for these complex structures. A multidisciplinary SHM...

Structural health monitoring for fatigue life prediction of orthotropic bridge decks

Infrastructure asset owners are more and more confronted with structures reaching the end of their structural life. Structural Health Monitoring (SHM) systems should provide up-to-date information about the actual condition, as well predict the structural life and required maintenance of the assets for more cost effective and reliable operation...

Coating based Fiber Bragg Grating humidity sensor array

A coating based FBG humidity sensor is developed for distributed humidity sensing. The sensitivity of the coated FBG is optimized by varying the chemical composition and the thickness of the coating. A sensitivity of ~2 pm/%RH and a rapid response are demonstrated. The composition of the coating can be adapted for sensing other chemical elements...

A new fibre-optic sensor for high-temperature flow measurement

Measuring flow is essentia ìn the process and oil & gas ìndustry. In the oil and gas industry, orifice plates and vortex meters are popular, since their lack of moving parts makes them robust. However, the need for electronics limits maximum process temperatures to 150 to 200'C. Special electronics can go up to 1100'C, but this makes the meter...

Fiber Bragg distributed chemical sensor

A distributed chemical sensor is developed by coating multiple Bragg gratings in a single glass fiber with chemical responsive coatings. The composition of the coating is tuned to the target chemicals to be measured and the optical response of the coated grating is optimized by changing the coating thickness. Specific recoaters were used to...

Development of a FBG vortex flow sensor for high-temperature applications

A robust fibre optic flow sensor has been developed to measure liquid or gas flows at ambient temperatures up to 300°C and pressures up to 100 bar. While such environmental conditions are typical in pressurized steam systems in the oil and gas industry (downhole and surface), wider applications are envisaged. The flow sensor uses a specially...

A fibre-optic based distributed chemical sensor

Fiber Bragg distributed chemical sensor

A distributed chemical sensor is developed by coating multiple Bragg gratings in a fibre with chemical selective responsive coatings. The optical response of the coated grating is optimised and the recoat process is very reproducible.