Research On Damage Monitoring Technology Of Morphing Wing Composite Material Skin Based On Spectrum Analysis Of Fiber Bragg Grating

In this paper, the morphing wing aircraft is focused which is the frontier subject for futureaircraft development, and its starting point is the new demands of morphing wing aircraft structurehealth monitoring, the research is a synthesis of fiber Bragg grating sensors, advanced compositestructures, structure health monitoring, methods about damage monitoring and active deformationmonitoring based on strain sensing principle and non-uniform changes in the reflection spectrumcharacteristics of FBG sensors is proposed.The main contents are as follows:the spectrum reconstruction algorithm of fiber Bragg grating sensor: By Analysis the existingfiber Bragg grating sensor spectrum reconstruction algorithm, innovatively import the gradientfactor to the transfer matrix method, then the improved transfer matrix method that with highlyiterative rate and more sensitively about the change of strain field can be obtained. Validation testsshows that the iterative rate and the exactitude of improved transfer matrix method has beensignificantly improved improved transfer matrix method,The damage monitoring of morphing wing skin: The failure process of composite corrugatedflexible skin under tensile load is studied, a prediction of failure sequence of ply and the criticalfailure load is given by finite element analysis, the critical failure spectrum of predicting failureply is reconstructed by improved transfer matrix method, proposed a method about utilize thevariation of FBG sensor non-uniform reflection spectrum to monitoring progressive damage ofcomposite corrugated flexible skin, static tensile test results shows that the critical failure load,corresponding critical spectrum were consistent with the experimental findings, the maximumerror of critical failure load is8.6%; accentuate the tensile properties and failure behavior ofcomposites honeycomb core structure, Proposed the use of regularly change mode of FBG sensorreflection spectrum to monitoring composites honeycomb core structure failure process, by theexperimental study of different dimension cell unit composites honeycomb core study, obtainedthe relationship among the honeycomb failure process and the variation of FBG reflectionspectrum, then could integrated finite element analysis and each experimental results verify thefeasibility of this method.Composite flexible surface deformation monitoring and surface reconstruction: Based on thestrain sensing principle of FBG sensors, the sensing principle could establish the correspondenceamong the real-time curvature changes where the sensor is located and the center wavelength, then the surface curves can derive by the curve reconstruction algorithm. Validation experiments showthat the reconstructed surface and the visual record results are consistent, additionally, the systemowned a high response speed.The seeking of non-uniform FBG reflection spectrum reconstruction algorithm improvementsand spectroscopy applications has matched the non-uniform FBG reflection spectrumcharacteristics change with composite material structural damage, which provide research baseand reference of the study of new composite skin damage monitoring; Establish a functionalrelationship among surface curvature and center wavelength, to provide new ideas for the flexiblesurface deformation monitoring at the same time broaden the applications scope of FBG sensors.