FBG Sensors for power plants

FBG Sensors for power plantsNowadays researchers tend to use fusion as a safe energy source at power plants. Nevertheless, this process is dangerous. It requires reliable fiber optic technology for structural health monitoring at power plants. Novel fiber optic sensors offer robust operation in the harsh conditions of a commercial fusion power plant.

To be more precise, these fiber sensors provide temperature sensing applying optical fibers with written fiber Bragg gratings (FBGs). The FBG operating principle is based on broadband light that is directed on it. Although most of the light goes through, one wavelength is reflected. Herewith, the reflected wavelength changes with both temperature and strain.

Therefore, the installation of several fiber Bragg gratings enables performing independent temperature sensing of each location. Standard FBGs are widely used in various industries for strain and temperature sensing. Herewith, compact superconducting cables use these optical fibers based on fiber optic technology.

Novel FBG sensors can maintain “the intense electrical, mechanical, and electromagnetic stresses of a fusion magnet’s environment.” The novel fiber optic technology supposes ultra-long fiber Bragg gratings of 9-millimeter located 1 mm apart. The FBG sensors operate as conventional long quasi-continuous systems.

Compared to standard systems, FBG sensors include such benefits as long grating length (meters instead of millimeters). Ultra-long FBGs allow for sensing simultaneously occurring temperature changes along their entire length. Thus, it is possible to determine fastly temperature variation, irrespective of the location of the heat source.

Additionally, it is possible to combine ultra-long FBGs and traditional FBGs to produce both spatial and temporal resolution. The fiber optic technology has been developed by a team of researchers from Switzerland. According to them, such a combination can be used on bigger cables.

These FBG sensors detect quickly and accurately even the smallest temperature changes under realistic operation conditions. Moreover, they demonstrate a better signal-to-noise ratio thanks to their high level of sensitivity and the opportunity to adjust the optical fiber response.

Thus, the fiber optic sensors locate quench events tens of seconds faster than voltage taps. Herewith, the application of FBG sensors for HTS magnets quenches detection is very potential. It allows for overcoming the current problem of  HTS coils from damage during quenches.

Finally, such a fiber optic technology plays a crucial role in compact fusion processes, where practical, high-field, high-temperature superconducting magnets are important. FBG sensors are still under development and need some improvements to be used in new applications.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

Development of Fiber Bragg Grating Sensors for Aircraft Structural Health Monitoring

FBG sensors for aircraft monitoringThe use of composite materials in modern aircraft has been growing because of the numerous advantages that they provide. Generally, composite materials are less sensitive to corrosion, have enhanced fatigue behavior, and higher specific mechanical properties when compared to traditional materials used in aerospace applications. By contrast, composite materials have problems with damage detection which is an important procedure in the air transport industry. The main issue that occurs during the process of use is the separation of laminae from each other which happens on the inside of the material and is hidden from the outside. Nondestructive methods of aircraft testing are not effective enough for material monitoring.

Structural health monitoring consists of placing measuring and sensing devices on a structure to record, localize, analyze, and eventually predict damage. Most structural health monitoring techniques strive to measure the needed data in a non-destructive way. Fiber Bragg grating sensors are optimal for measuring different variables as they are more cost-efficient, easy to implement on most surfaces, including composite materials.

Aircraft structures require regular, scheduled inspections and monitoring of all possible hazards due to their special conditions and the principles of their design. Therefore, structural health monitoring is conducted through fiber optic devices and has great potential to reduce the costs related to these operations. Fiber Bragg grating sensors have proved to constitute the most promising technology in this field. In order to prolong the operation period of all kinds of complex engineering systems and avoid catastrophic failures, so it is necessary to achieve the highest levels of damage detection. The automation of the inspection process is a point of major importance to reduce inspection efforts. The structural health monitoring system on the basis of fiber optic products can be defined as a set of devices that provide information that allows us to locate, evaluate, and predict the loading and damage conditions of a structure. The structural health monitoring of aircraft structures can conduct real-time checks, reducing costs, and improving the reliability and performance of the structures. A wide range of potential structural health monitoring technologies is being developed to meet these needs, and the most promising options are:

  • electrical strain gauges and crack wires
  • acoustic emissions methods
  • optical-based technologies
  • comparative vacuum monitoring
  • microelectromechanical systems (MEMS)

Fiber optic products and fiber optic devices, in general, are very appropriate to perform structural health monitoring due to the fact that they have their intrinsic capabilities, such as sensitivity to electromagnetic radiation, low weight, compact size, great sensitivity and resolution, and their suitability to be embedded into structures. Fiber optic devices for monitoring the strain in aircraft structures can be classified into the following categories: intensity-based, interferometric, distributed, and grating-based fiber optic devices.

Among grating-based sensors, FBGs and probably the most mature and widely employed optical sensors for structural health monitoring of engineering structures due to their fast development achieved in recent years.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line: fiber Bragg grating sensors, FBG interrogators and multiplexers, distributed temperature sensing (DTS) systems. We create and supply a broad variety of top-notch fiber optic solutions for the monitoring of various facilities all over the world.

If you are interested in Optromix FBG sensors, please contact us at info@optromix.com