Study On Polymorphic Time-varying Reliability Of Radar Mechanical And Electrical System

As a critical index of production performance,reliability gets much attention.However,how to make reasonable reliability analysis and assessment faces many difficulties for radar electromechanical system.There are many problems needing to be solved,such as how to describe the uncertainty of complex service correctly,how to establish model for system multi-states and parts failure,and how to calculate the structural dynamic reliability based on the loss mechanism.In traditional reliability theory,components or systems follow binary logic.Since the functions and structures of products are becoming more and more complicated,traditional reliability theory cannot describe the practical states of components and lack sufficient ability to assess the reliability of complicatedelectromechanical system.Therefore,radar electromechanical system should be studied based on the idea of system science,the application of multi subject knowledge,exploration and research of new reliability analysis and evaluation technology.Based on the above considerations,this paper studies the reliability modeling,simulation,analysis and evaluation technology for the radar electromechanical system.Specific contents are as follows:(1)Multi-level reliability model for radar electromechanical system and reliability-redundancy allocation algorithm are proposedThe radar electromechanical system is a typical electro-hydraulic system.It is composed of parts,electrical equipment,electronic components,hydraulic components and other units.Each unit has different function and status.They also have different effects on the system reliability.Therefore,a more reasonable approach should be taken to handle each unit impact on the system reliability when building the system reliability model,so as to help engineers recognize system weaknesses and design reliability optimization easily.Based on the considerations above,hierarchical analysis method is used to deal with the hierarchical structure for radar electromechanical system.The Multi-level reliability evaluation index system is constructed.A method of constructing multi-level reliability model based on weight coefficient is proposed.The effectiveness of the proposed method is confirmed by a case study,which can meet the need of reliability analysis and evaluation during the development of radar electromechanical system.In order to meet high reliability requirements,how to balance the development cost,system weight and volume limit,and reasonable distribution for reliability index are existed in the design of radar electromechanical system.To solve this problem,this paper proposes a hybrid optimization algorithm based on IPSO,which makes full use of the advantages of particle swarm optimization and genetic algorithm in local search and global search.The result of case analysis shows that the algorithm has strong global optimization ability,and it can achieve the optimal allocation of reliability index of large-scale complex electromechanical system.(2)A method for reliability analysis of multi state system based on DBN is proposedTraditional reliability theory is based on the classical probability theory and the two state hypothesis,and it is considered that there are only two states of the system: normal or failure.The relationship between the performance of the components and the system performance,the relationship between the system reliability and the system performance can not be solved.and the theory can hardly model and evaluate the reliability of the system.In view of the above problems,reliability analysis of multi state system based on DBN is presented.Based on the function analysis,this paper applies the structural analysis and design technology to get the function movement and the corresponding functional requirements of the electromechanical system,and completes the construction of the functional network of the system.Then the failure mode and effect analysis technology are used to analyze the function and the requirement of the failure.The construction of the failure network and the definition of the multi state are completed.Finally,the failure network is mapped to the function network,and the Dynamic Bayesian Network model is transformed into the Dynamic Bayesian Network model.(3)A modeling method of structural dynamic reliability based on upcrossing approach is proposedThe damage of the radar mechanical structure under the environment load is continuously developping,the performance of the material is gradually deteriorating,and the working stress state presents the dynamic evolution characteristics.The gradual failure modes include wear,fatigue,corrosion and so on,which lead to the difficulty in constructing the dynamic reliability model and calculating the transient failure probability and the cumulative failure probability.Given the above questions,based on the generalized stress-strength interference theory,degradation mechanism of corrosion,fatigue and wear are analyzed,the structure dynamic reliability modeling method based on upcrossing approach are put forward.The dynamic reliability computation translate into transient failure and cumulative failure problem.Stochastic finite element analysis method is adopted to solve the problem of calculating the failure probability of the transient.Considering the failure correlation of adjacent time,the failure probability can be calculated based on the cumulative upcrossing rate calculation method.Therefore,the calculation of structure dynamic reliability is completed.(4)A prototype system for the reliability analysis and evaluation of radar electromechanical system is developed.Based on the above research,the development of "ground analysis and reliability evaluation of high mobility radar mechanical structure software" and "ground radar with high mobility polymorphism electromechanical system reliability analysis software",and then integrated in a unified interface,the formation of "analysis and evaluation software system reliability of ground radar with high mobility of Mechanical software”.Furthermore,the achievement of the software,database and the proposed methods can be extended to other military equipment in the development of mechanical systems,which has a certain value of the industrialization of the potential.