Flexible Structure Deformation Monitoring Technology Research Based On Distributed Optical Fiber

During the process of long-term service,the morphological form of aerospace structure can be easily changed by its own excitation or external environment disturbance,which would lead to the damagement of self-safety and service-life of aerospace structure,as well as the reliability of the work performance of the structure.Thus,the deformation monitoring of aerospace structures not only can provide the foundation for precise control of morphological and active suppression of vibration,but also for structural health condition assessment is of great significance.Therefore,the deformation monitoring of different flexible structures based on Fiber Bragg Grating(hereinafter referred to as FBG)sensors have bas been discussed in this thesis.By studying different deformation reconstruction algorithms,the deformation condition monitoring of different flexible structures with different properties has been realized.The main research contents can be divided into the following several aspects:Firstly,based on the principle of strain-sensing of FBG sensors,the integration method of FBG sensing system with measured object structure was been studied.Besides,the strain-sense characteristics of FBG sensor such as strain sensitivity and linearity,precision,hysteresis and repeatability were been measured and analyzed,which would be provided support for the subsequent deformation monitoring.Secondly,according to the particularity and deformation characteristics of the aerospace structure,the Ko displacement theory and plane coordinate transformation deformation monitoring and reconstruction methods based on distributed optical fiber of plate-type structure have been studied respectively,and the corresponding deformation monitoring system of composite material plate structure has been built.Both of the finite element simulation and test methods have been used,and varieties of error forms have been chosen to be the indexes of deformation reconstruction effect evaluation.Thirdly,the deformation monitoring system of aluminum alloy wing structure has been built.By using of the Ko displacement theory and plane coordinate transformation deformation reconstruction methods,the non-uniform cross-section wing structure deformation inversion under different loading modes have been realized respectively.On this basis,the deformation monitoring and real-time display system based on LabVIEW interface has been created out.Finally,according to the deformation characteristics of flexible tubular structure,the space coordinate transformation shape perception based on distributed optical fiber of tubular-type structure has been studied,and the three-dimensional deformation reconstruction of flexible tubular structure has been realized preliminarily.