Applications of Fiber Bragg Grating Sensors in the Composite Industry
- PDF / 2,246,523 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 45 Downloads / 196 Views
Applications of Fiber
Bragg Grating Sensors in the Composite Industry
Pierre Ferdinand, Sylvain Magne, Véronique Dewynter-Marty, Stéphane Rougeault, and Laurent Maurin Abstract Optical-fiber sensors based on fiber Bragg gratings (FBGs) provide accurate, nonintrusive, and reliable remote measurements of temperature, strain, and pressure, and they are immune to electromagnetic interference. FBGs are extensively used in telecommunications, and their manufacture is now cost-effective. As sensors, FBGs find many industrial applications in composite structures used in the civil engineering, aeronautics, train transportation, space, and naval sectors. Tiny FBG sensors embedded in a composite material can provide in situ information about polymer curing (strain, temperature, refractive index) in an elegant and nonintrusive way. Great improvements in composite manufacturing processes such as resin transfer molding (RTM) and resin film infusion (RFI) have been obtained through the use of these sensors. They can also be used in monitoring the “health” of a composite structure and in impact detection to evaluate, for example, the airworthiness of aircraft. Finally, FBGs may be used in instrumentation as composite extensometers or strain rosettes, primarily in civil engineering applications. Keywords: composite materials, fiber Bragg gratings, laminates, mechanical properties, optical-fiber sensors, optoelectronics, optical properties.
Introduction Composite materials have been used for many years in the aerospace industry, owing to their high specific stiffness and strength. They are also used more and more in the transportation industry, and in mechanical engineering and civil engineering for the rehabilitation and reinforcement of structures and cables. Composites display good short-term and long-term (fatigue) mechanical behavior, and good environmental stability (withstanding fire, corrosion, lightning strikes, etc.). Optical-fiber sensors have been embedded into composite materials for more than 12 years.1 For aerospace applications, we may distinguish three main applications for optical-fiber sensors, one related to manufacturing control, a second linked
400
to “health” diagnostics (in-flight or for maintenance), and a third related to smart structures (control damping and shape control).2 Embedded optical-fiber sensors may be used to provide in-flight, real-time information to an on-board controller able to drive actuators with the purpose of damping vibrations or noise, or controlling the shape of a structure: this is the well-known concept of smart structures, that is, structures able to sense their environment and to correct autonomously for any perturbation. Until now, much of the research in this area has been directed toward the use of optical-fiber sensors in the continuous improvement of manufacturing processes. During the manufacture of composite ma-
terials, it may be necessary to monitor temperature, pressure, void content, resin front progression, shrinkage, or residual stress, as well as inline cure m
Data Loading...
