Research On The Testing And Data Processing Technology For The Health Management Of The Aero Hydraulic Pipeline System

The damage and failure of aero-hydraulic pipeline system takes places frequently under areo engine high pressure impact and strong body excitation,and further endangers normal flight operation and safety.Currently there is no PHM system established and applied for aero hydraulic pipeline system.Therefore,the breakthrough of key data measurement technology,the analysis to key test data,the acquisition of characteristic parameters containing in vibration signal and reflecting operation status,the identification and prediction of the operating status changes,and the diagnosis prior to accident occurance contributes significant importance and engineering value to safe moperation and maintenance of aero hydraulic pipeline system.Aero-hydraulic pipeline health management system PHM(abbreviation of Prognostics and Health Management)is information transaction platform which to use data and information collecting by sensors,evaluate system health condition assisited by various data process,forecast pipeline system failure and finally provide maintenance assurance measures referring to available information resources.Currently Aero-hydraulic pipeline health management system is one of important national research tasks and been included into civil aircraft prime projects.This article carried out preliminary research and key technology breakthrough based upon cooperation research project with AVIC Aero-Engine Research Institute.In allusion to urgent demand for effective process to key test data from complicated operation condition by Aero-engine hydraulic pipeline PHM system,the article developed research upon key test technology such as aero-engine hydraulic oriented fiber Bragg grating sensor measurement technology;research upon data processing technology focused on frequency analysis technique and nonlinear transform technology.On the foundation of Fiber grating sensing and demodulation theory,wavelet analysis and wavelet packet decomposition theory,Hilbert Huang transform(HHT)and nonlinear dynamics and chaos theory,nonlinear transform technology,the article archived to key test technology on installation and layout of strain pipeline system dynamic fiber grating sensor,key test technology as temperature decoupling and wavelength demodulation,implemented pipeline system solid characteristics measurement and test run condition dymatic measurement;performed wavelet analysis,wavelet packet decomposition,HHT analysis,phase space reconstruction and nonlinear qualitative analysis to vibration non-stable signal from different pressure condition and changing process,mastered hydraulic pipeline system complicated vibration action excitated by hydraulic pump pressure and airframe stress.The main achievements in this article are as following:1.To proposed Fiber Bragg grating(FBG)sensor-based aero hydraulic pipeline distribution test technology,and realize hydraulic pipeline fault position and judgment.By comparison of hydraulic pipeline system vibration characteristics-gained from fiber Bragg grating sensing to traditional electrical measurement technology,verify accuracy,feasibility and advantage of fiber Bragg grating technology in aero-hydraulic pipeline system PHM.2.To propose different pressure pipeline vibration signal time frequency analysis technology.On the basis of wavelet packet decomposition and HHT analysis technology,obtain pressure wave instant vibration characteristics caused solenoid valve swiching on&off,thus overcome disadvantage of traditional Fourier transform technology which can not obtain instant frequency information,provides a new technology for non-stable vibration analysis on condition of aero hydraulic pipeline pressure wave.3.To propose nonlinear qualitative analysis technology of pipeline vibration signal under different pressure condition,discover pipeline system status changes from periodic and quasi periodic motion to chaos with hydraulic pressure incresement.Discovering the complexity of pipeline vibration signal decreases,increases afterwards along with hydraulic system pressure increasement,realizes qualitative identification of nonlinear characteristics for aero hydraulic pipeline system.4.To propose nonlinear prediction of vibration signal for pipeline under different fluid pressure subject to nonlinear quantitative analysis technology,Based upon nonlinear parameter estimation method as correlation dimension,maximum Lyapunov exponent and data alteration method,accurately extract the pipeline operation characteristics and identify the operation status,and provide a creative thought for aero-hydraulic pipeline system health monitoring and real-time diagnosis.