The use of Fiber Bragg Grating Sensors During the Static Load Test of a Composite Wing Structure

The article describes process of implementation of optical Fiber Bragg Grating (FBG) sensors into the composite wing structure and their behavior during the strength test. The wing is of all-composite construction. The upper and lower skins are made of glass/epoxy composite. The spar caps are made of carbon/epoxy unidirectional composite. Optical fibers were integrated directly into the spar caps and into the adhesive joints. They were oriented in parallel with the main spar axis. The first optical fiber with chain of multiple FBG sensors was integrated into the structure of upper spar cap. Another FBG chain of FBG sensors was located in the adhesive joint of lower spar cap and shear web. The wing was instrumented with strain gages as well. Strain gages were glued to the sides of the spar caps. Static load was produced by a hydraulic actuator. Experimental results from strain gages and FBG sensors were compared with the results of the analytical analysis of the wing.