Storage Reliability Assessment Method Of Relay Subsystem Based On Performance Degradation

Modern weapons and equipments such as missiles and torpedoes are generally characterized by "long-term storage,one shot".In order to ensure that the maintenance and inspection of weapons and equipments during the service can be carried out scientifically and reasonably,it is an essential prerequisite to accurately assess the storage reliability of each components.Electromagnetic relays have the lowest reliability among all kinds of military electronic components.Therefore,as the key units of weapon and equipment systems,a relay subsystem(RS)with the core components of electromagnetic relays becomes the shortest board to determine the storage reliability of its belonging system.However,at present,there are still rarely related researchs on the storage reliability of RSs in and abroad.Among them,little assessing methods could play a guiding role in engineering practices.This dissertation researches on the main problems existing in the storage reliability assessment of RS,such as unclear failure mechanisms and degradation characterization parameters,traditional system reliability simulation technologies are difficult to work,blank of storage reliability assessing method considering manufacturing process,lacking of testing and monitoring approaches and so on.The main purpose is to start from the basic research of storage failure mechanism,with the combination of experiment,manufacturing process and simulation,explore a set of storage reliability research technology system for the RSs.So as to lay the technical foundation for accurately assessing and fundamentally guaranteeing the storage reliability of both the RSs and their belonging systems.Firstly,the mechanisms and characteristics of the RSs' storage degradation process are analyzed.Based on the function and structural characteristics of RSs,key components and materials are identified.Based on the storage degradation data of key materials(Ag-Mg-Ni alloys and Al Ni Co),the micro-mechanisms and performance parameters' evolution law of the stress relaxation of reed and the aging demagnetization of permanent magnet are explained from the perspective of dislocation motion and magnetic domain,respectively.On this basis,the RS co-simulation methods under the condition of key material degradation are given.Then,by means of multiple regression and correlation analysis,the storage degradation characterization parameters of the RS which can reflect the storage degradation of the key components as well as directly relate to the bottom level mechanisms,are determined.Therefore,it lays a foundation for designing storage accelerated degradation test schemes,developing targeted test monitoring systems,and accurately assessing the storage reliability of RSs.Secondly,the research on degradation-simulation-based storage reliability assessment methods of RS is carried out.The stress relaxation constitutive equations of Ag-Mg-Ni alloys corresponding to different initial stresses are constructed,and the stress relaxation simulation of the cantilever beam relay reeds is realized.The reed flexiability storage degradation model is constructed by introducing the storage-time-related variables in the deformation energy method.With the medium of start work point B,by combining the finite element simulation of relay electromagnetic system,a permanent magnet suction torque storage degradation model which can reflect the influence of parameter fluctuation is constructed.Combining the storage degradation models of the reed flexibility and the permanent magnet suction torque with the electromagnetic relay dynamic characteristics equations,a approximate calculation method for relay storage degradation is given.Based on the RS simulation model,the degradation process of the storage degradation characterization parameters is simulated.Copula function is used to construct the RS's storage reliability model,and the degradation-simulation-based storage reliability assessment of the RS is realized.This method can provide a new technical means for the assessment of RSs' storage reliability in the case of no test data or design stage.Then,manufacturing-process-based storage reliability assessment method of small sample RS is studied.Traditional reliability assessment methods have unguaranteed accuracy.To address this problem,a manufacturing-process-based storage degradation modeling method for electromagnetic relay is proposed.On this basis,the storage degradation data of batch relays are obatined based on the small sample testing data and relay simulation.After that,the simulation expansion of RS sample size and the acquisition of initial distribution of performance parameters are realized.Aiming at the two kinds of more objective and accurate pre-test information(the data of RS expansion samples and the initial distribution of performance parameters),two corresponding methods of priori information transformation and multi-source information fusion are studied respectively.By this means,the results of storage reliability assessment and the room temperature storage life prediction of the RS with small sampling are given.Finally,the approach for storage reliability accelerated degradation test of RS are proposed,and the corresponding testing system is designed.Through the in-depth analysis of the influence of the main environmental stresses of the storage task profile on the RS's storage degradation process,a small sample accelerated storage reliability degradation test scheme for the RS,with temperature,humidity and electricity as test stresses,is designed.At the same time,a corresponding dedicated testing and monitoring system is developed for the effective implementation of the test scheme.The system can automatically complete the test according to the established scheme,and simultaneously monitor the degradation process of the performance parameters of 40 relays and 4 RSs.It can cope with the problems of large time span and small changing of degradation characterization parameters per unit time in the RS's storage acceleration test.A large amount of test data is obtained from the one-year accelerated storage degradation test,which provides a guarantee for the study of the storage reliability of the RS.