Life Evaluation For A Hser Based On A Degradation Model Of Contact System

The reliability of electronic components has become the main influencing factors of weapon equipment failure.Hermetically seal electromagnetic relay(HSER)is the most unreliable device,and it is the shortest board of all electronic components.Therefore,it is urgent to evaluate the reliability of HSER especially about the life.At present,most of the research on relay degradation takes the performance parameters of the whole machine(make time,make voltage,etc.)as the characteristic parameters of the degradation evaluation.Although the reliability evaluation and life prediction based on the performance parameters of the whole machine play a guiding role in the application of relay,it has no substantial effect on the optimization of relay and the improvement of its life.The fundamental reason is that the life evaluation model based on characteristic parameters of HSER can not directly reflect the causes of failure(contacts failure),electrical parameters excessing(contact resistance,make and release voltage,etc.)in the working process,so it is impossible to fundamentally find the reasons that lead to the poor reliability life of HSER and can not provide the guidance in life design to improve reliability..In this thesis,the degradation failure mechanism of relay contact spring system under cyclic load is analyzed,and the quantitative modeling and analysis of performance degradation of relay contact spring system are realized by combining the theory of random uncertainty.Based on the over-range and gap degradation model of assembly process,the life evaluation of HSER considering the degradation of contact spring system is completed.Firstly,the author carries out the reliability life test under rated working conditions,determines the specific performance index of a certain type of relay,analyses the failure mode and failure mechanism,and at the same time determines the sensitive degradation parameters of contact spring system(spring over-range,contact clearance),and puts forward the optimization target of reliability life,i.e.the threshold of reliability life failure determination,for the follow-up reliability life.Life assessment and reliable life quantitative design lay the foundation.Secondly,according to the requirement of life evaluation of HSER under different working conditions,the experimental scheme of performance degradation of contact spring system is designed,and a method of data acquisition for assembly parameters degradation of contact spring system based on laser displacement sensor is proposed.The experimental system is built to acquire and analyze assembly parameters degradation data under different working conditions.The trend of degradation trajectory is analyzed,and a stochastic process degradation modeling method considering process dispersion is designed.The contact clearance and reed over-range degradation models under different working conditions are established.Then,the 3D assembly prototype model of relay is established using Solidworks,and the static make and reaction characteristics of HSER are calculated by using FEM software ANSYS and FLUX.Based on the static make data table obtained by static simulation,the dynamic characteristics of relay are obtained in MATLAB/Simulink module,and the virtual prototype platform is built.Based on the prototype platform,the performance change of the HSER contact spring system under the condition of performance degradation is obtained,and the corresponding degradation threshold of assembly parameters of the contact spring system is calculated.Finally,the correlation between assembly parameters,reaction force and assembly parameters of contact spring system is quantitatively analyzed by convex set calculation model.Based on the correlation degree of assembly parameter degradation of contact spring system,the appropriate Copula function is selected to link the over-range and gap single parameter degradation reliability function.Finally,a joint reliable life model considering the degradation of relevant binary factors is established,and the life evaluation is completed.