Reliability Research Of Missile Tester Based On Fault Tree Analysis

With the development of modern weapons,more strict requirements are put forward for the part of electronic equipment on missile,such as guidance unit,control unit and parameter acquisition unit.In particular,the reliability of the missile-borne electronic system is related to the stability and security of the weapon.The key components of the missile-borne electronic system are discrete components,integrated components and the corresponding connected fixed components.The board-level reliability of missile-borne tester is determined by the selection,welding and board-level connection of each electronic element.At present,domestic and foreign scholars in this field have done a lot of tests from the aspects of environmental temperature,environmental static stress,environmental dynamic stress,natural aging,electromagnetic interference and so on.The study of reliability has received more and more attention from researchers in the field of military industry.Therefore,through some scientific methods,theoretical analysis,simulation experiment,live ammunition experiment to carry out the classification reliability research on the missile tester circuit,is helpful to find the weak link,improve the reliability of the system,and has important significance to establish the reliability theory of the system missile tester and master the rapid failure repair experience.The specific research in this paper is as follows:(1)Study on failure mechanism of component level of missile borne tester.Firstly,the methods of nondestructive analysis and failure analysis for failure diagnosis are summarized,and the definition of basic concepts is given.Then,according to the different failure modes and failure mechanisms,the circuit of the projectile tester is divided into five parts: LCR chip element,semiconductor integrated circuit,MEMS,solder joint and PCB.According to the failure phenomenon,the failure mechanism was systematically studied,the relationship between component structure,assembly mode and system failure was analyzed,and the failure criterion determination system was improved.(2)Reliability enhancement experiment of missile-borne tester.With the help of high and low temperature box,impact table,Marchette hammer,strong magnet and other experimental equipment to simulate high and low temperature,impact vibration,electromagnetic interference and other harsh environment,focusing on the use of mechanical stress strengthening test for reliability assessment,the circuit part of the developed projectile test instrument repeated experiments and step experiments.The influence factors of environmental stress on the component level reliability of the system and the weak links of the system are found,and the relationship between environmental stress and the component level failure mode of the missile-borne tester is established.(3)Establishment of FTA system for missile-borne tester.The downlink method is used to find the basic events leading to the occurrence of the top level event(board level failure),the probability distribution of the basic events is determined according to the priori theory and statistical law,and the qualitative and quantitative analysis of the reliability is carried out.The minimum cut set,the smallest path set,the structural importance degree,the probability importance degree and the critical importance degree of each basic event of the fault tree are determined successively.By establishing the failure analysis logic from the board level system and evaluating the importance of the basic failure events in each part,the weak links can be protected with emphasis.Finally,the projectile recorder that failed in the process of penetrating the hard target was used as the verification platform.By using the reliability model studied in this paper,the fault can be located,repaired relatively quickly,and the data before the failure in the penetration stage can be read,which verifies the scientific nature and practicability of the reliability model of the missile-borne tester based on the fault tree model.According to shortcomings of system experiment design,the requirement of comprehensive reliability test is put forward to solve the defects of current single environment test.