Research On Depedent Competition Failure Ofmechainal System In Reliability Evaluationmethod And Maintenance Policy

From the perspective of system failure mechanism,the common reliability failure modes are mainly composed of degradation failure and sudden failure.Degradation failure of system is a natural attribute.Its performance degrades with the increase of time.When the degradation exceeds a certain threshold,the system will lose its effect.Sudden failure is the sudden loss of system performance due to some reason,resulting in the failure of the system.In fact,the system failure is caused by the complex competition between degradation failure and sudden failure usually.In the reliability evaluation of system,the correlation between the interaction between degradation failure and sudden failure should be considered,and appropriate analysis methods should be adopted to analyze the failure data,so as to reduce the error of system reliability evaluation.In this paper,considering the correlation between failure modes,the component reliability model is established under the coexistence of sudden failure and degradation failure,including the following contents:(1)The reliability modeling problem considering the competing failure processes of degradation failure and sudden failure under the impact of non-stationary Poisson with degradation rate changes is considered.The non-stationary random impact process with increasing amplitude and intensity describes the sudden failure process based on the linear process,and the reliability of the system is studied when the degradation rate of the system degradation process is increased due to the impact exceeding the critical threshold.(2)The problem of system reliability evaluation is researched where correlation between degradation failure and sudden failure is under swifting threshold.Based on the extreme impact process,the correlation of system failure are the impact increasing the degradation of the system,and the degradation process affecting the hard degradation process of sudden failure with the change of failure threshold.The degradation process is described to analyze the effect of system performance degradation on sudden failure degradation by linear process.Reliability of the system under swifting failure threshold is researched.(3)In order to solve the reliability problem of two failure modes competing with each other in the system,a reliability evaluation method of correlation competition failure between sudden failure and multiple degradation failure is proposed.The multi-degradation failure process of system is described by suitable random process and the Copula function was utilized to model the multi-degradation failure process of system.Moreover,a two-parameter Weibull distribution is utilized to describe the sudden failure process,which the conditional probability that suddenfailure based on degradation failure is acquired.After estimating the relevant parameters,the correlation competition failure model of mechanical system is deduced.(4)Degradation failure and sudden failure in mechanical system affect the performance of the system together.In order to ensure the normal operation of the mechanical system,it is necessary to inspecte and maintain it frequently.Aiming at the lowest cost of system maintenance,the stationary Markov process is utilized to describe the maintenance process of the system.The degradation failure process of the system is divided into several states.The function of maintenance rate relating maintenance cost is established,which can be solved to obtain the minimum maintenance cost of the system.