Multi-parameter Identification Of Typical Aircraft Components Based On Distributed Optical Fiber

Structural health monitoring relies on various advanced sensing technologies to acquire and evaluate real-time damage,deformation,load and other types of information of Engineering structures,which plays a key role in the safety and integrity of structures during service.In recent years,the related research in the field of structural health monitoring has grown rapidly and made a series of great progress.Distributed optical fiber sensing technology has been rapidly developed and applied because it can form a distributed sensing network to achieve continuous monitoring of the structure and meet the needs of structural health monitoring.In this paper,an on-line identification method for multi-parameter information of typical aerospace components based on distributed optical fiber sensor network is proposed.Taking special-shaped thin-walled beams as the main research object,the online joint identification of structural damage,shape,stress/strain distribution and other parameters under complex load coupling is realized.The main contents include:The first chapter introduces the background and significance of this paper,including the content and main role of structural health monitoring,the overview of structural multi-parameter information identification methods,and the development status of advanced sensing technology such as distributed optical fiber.The second chapter introduces the theory of complex deformation reconstruction of thin-walled beam with special-shaped cross-section,and establishes the method of deformation decoupling and reconstruction of channel section beam under multi-load type coupling.The validity and reconstruction accuracy of the method based on the numerical simulation results of finite element model are verified,the reconstruction accuracy of bending and torsion deformation is good.And then puts the focus on the effect of deformation reconstruction under measurement noise environment.The noise immunity is proven to be strong up to considerably large noise level of being 30%.In the third chapter,aiming at the joint identification of multi-parameters,the joint identification of multi-parameters under complex loads is realized for the thin-walled beam model with damaged groove section,then puts the focus on the effect of structural damage on the accuracy of deformation reconstruction under different degrees of damage.It is found that the damage condition has little effect on the deformation reconstruction algorithm.In the fourth chapter,the real-time dynamic display function of three-dimensional strain nephogram is developed for distributed optical fiber sensing technology,and the strain monitoring system of aircraft truss structure based on distributed optical fiber is constructed.Taking L-section thin-walled beam as the research object,strain distribution measurement and damage identification based on distributed optical fiber sensing technology are realized.In this thesis,a multi-parameter information identification method for thin-walled beams with special-shaped cross-section under complex loads is established.Strain measurement and damage identification of beams based on the self-developed optical fiber software module are realized.The research results have application value in state sensing,deformation control and structural optimization design in aerospace,automobile,ship and other fields.