Structural health monitoring of composite wing structure during durability test

FBG (fiber Bragg grating) sensors were applied to durability tests of a composite wing structure in order to verify its health monitoring capabilities for long-term use. The durability tests included drop-weight impact tests and two periodic fatigue tests based on the design service life of the aircraft. The seven FBG sensors were installed to the surface of the test panel for the monitoring of impact damages and fatigue tests. The impact damages were detected by using the spectrum change of the sensor output. The strain changes during the fatigue tests were measured by the wavelength shift of the sensor output. The damage evolutions in the test panel were also evaluated by using NDI (non-destructive inspection) technologies: AE (acoustic emission) sensors, an ultrasonic C-scan, and pulsed heating thermography. Compared with results of the NDIs, the FBG sensors could output valuable information for monitoring the structural integrity of the composite wing structure. As a result, it was confirmed that FBG sensors have the capability for the long-term health monitoring of large-scale composite structures.