Reliability And Maintainability Assessment Of Warship’s Dynamical System Based On Field Maintenance Data

Warship is a complex synthesis with multi-system and multi- function. As the warship of the heart, the dynamical system not only provides propulsion power to perform a variety of tasks, but also supplies energy for various power system. The naval execution combat task will seriously affect once dynamical system fails. therefore, it has great importance to evaluate the actual reliability and maintainability of warship’s dynamical system.Field maintenance data is obtained when the warship sets sail or is maintained after failed, so it is more representative of the true reliability’s level and maintainability’s level of the warship in the actual environment. Above all, this paper chooses the warship dynamical system as the research object to assess its reliability and maintainability based on field maintenance data. The main research contents include:(1)Reliability analysis of non-repairable parts and calculation of spare partsRepairable parts and non-repairable parts both exist on board as for warship and other large equipments. Non-repairable parts refer to parts which are replaced with new ones and then abandoned once failing. Correspondingly, repairable parts refer to parts which are maintained to continue to use once failing. This chapter introduces the warship maintenance mode and the form of data acquisition and recording in detail. Warship is usually maintained periodically that failing non-repairable parts are replaced with new ones at monitoring point, which leads to the fault times unknown. The data gathered from maintenance recordings are disposed into interval-censored data. This chapter selects the Weibull distribution as the life distribution function of the non-repairable parts and establishes the reliability model based on the interval-censored data. Finally the spare parts’ amount on board of the non-repairable parts is calculated. The simulation analysis shows that this method can perfectly solve parameters.(2) Reliability analysis of key repairable parts of the dynamical systemKey repairable parts are selected as the research object and the Weibull Process is selected as the failure process model in this chapter, which aims at solving the Weibull Process parameter’s value through analysing the fault data of repairable parts. Then the trend of the repairable parts via time is analyzed and overhaul decision is made according to the parameter’s value. Accordingly, this chapter establishes the likelihood function using maximum likelihood estimation and iterate the function using EM algorithm to solve the problem that the interval-censored data is difficult to analyse using general methods. Finally the parameter’s value is obtained and The simulation analysis shows that this method can perfectly solve parameters.(3)Quantitative maintainability assessment based on field maintenance data of the warship dynamical systemIt is very difficult to record the maintenance time accurately when the warship ismaintained. The interval of maintenance time can be obtained roughly through the maintenance personnel’s working records. Maintenance time is selected as the quantitative evaluation index and Log-normal Distribution as the distribution function of maintenance time in this chapter, which aims at solving the parameter’s value of distribution function and analyzing the degree of coincidence between current maintainability level and the requirement of maintainability. Finally, the influence of assembly features on maintenance time is analyzed to achieve the purpose of expanding data to solve the problem of data’s lackness. EM algorithm is used to solve the problem that the interval-censored data is difficult to analyse using general methods and weight of influence on maintenance time of each assembly feature is obtained.