Development of Fiber Sensors integrated with Aerospace Composites for Structure Health Monitoring

Abstract

The wide-spread use of composite material in aircraft across the world is expected to create a big need to improve structure health monitoring (SHM). Optical fiber sensors offer more advantages than conventional sensors, such as light weight, small size, immune to electromagnetic interference, easily embedded in composites. Extensive applications have been reported with a few embedded technology details by Boeing and Airbus, etc. In this paper, The methods of improved optical fiber surface-bonded composites by glass cloth and epoxy resin, as well as optical fiber embedded in composites were researched. The installation of fiber and composites, composites assembly pressure adaptability on FBG sensors, influences on structure properties of composite materials due to different fiber diameters and different numbers of optical fibers by the way of microscopic interface analysis and C-san were studied. The adequate fiber embedded technology was found to obtain the most feasibility of SHM. Light intensity and wavelength of FBG sensor surface-bonded by glass cloth are affected by the structural assembly pressure. It can be seen that diameter of embedded optical fiber equal to the thickness of prepreg monolaye, the fiber embedded next to 0 degree layer, less than five fibers within a 25mm width composite unit have little impact on composite structure. Then, 12 FBG sensors were embedded in a typical aircraft structure, a carbon fiber enhanced stiffened composite plate with length 600 mm and width 600 mm, to detect position and energy of external impact load by a mathematical analysis method, cross correlation algorithm. Finally, suggestions on future study are listed from four aspects, co-forming technology of FBG sensor and composite skin, research on the extraction technology of optical fiber, new flexible wing testing technology and advanced fiber optical sensing technology.