Research On The Problem Of Spare Parts Based On Prognostics&Health Management

The research on Prognostics and Health Management (PHM) for com plexsystems is a hot topic in the current reliability field, its main idea is to change thesystem logistics from state monitoring to state management, which makes people payan attention actively on the system failures and risk of performance degradations, anddo the health management for complex systems. Based on the technology of PHM,the problem of Spare parts is given. It can significantly reduce the costs ofmaintenance and support and achieve economic affordability. Thus the dissertation issignificant in both theory and practice. The contents of the dissertation include threeareas in the problem of spare parts: Optimal allocation and reliability evaluation forsensor systems, which is a base for obtaining the system operation information inorder to provide identifiable ground for the model of Spare parts allocation; Modelingand method for prognostics under repairable systems of Markov and Semi-Markov,which is the core of this dissertation; The configuration model of the allocation ofSpare parts is constructed, which is an important content of assessment system of theability to maintain. All research results will be created originally, which will build anessential base on applications of PHM for complex systems in the future. The mainresearch parts of this dissertation as follows.Firstly, according to the environment of the measured component andPerformance parameters (such as vibration, displacement, velocity, temperature, noise,traffic, etc.) and other information, it select the appropriate sensor type by data fusionof multiple sensors in order to get a stable valid data. By aiming different levels (forexample system, complex system of subsystems etc.) and different types of sensors, itcan determine the demand for sensors and establish the model of multiple objectiveprogramming and obtain the optimal the objective function and the optimal criteria. Inorder to achieve the best results of the sensor system, this dissertation establish thesystem architecture of multi-sensor system and reliability model.Secondly, Monitoring data is usually obtained by the sensor of all levels andprocessing and analyzing the data. At the same time, this dissertation constitute thesystem of PHM for the important Spare parts.On this basis, it can set up theoptimization model of allocation of the Spare parts for the non repairable system.When the Spare parts failure, it can use the theory of renewal process and set up theallocation model of Spare parts for non repairable systems due to technical reasons, the economy as well as the system itself. At last, this dissertation gives therequirement of spare parts.Thirdly, the dissertation can construct the model of the allocation of Spares partsbased on Markov and semi-Markov processes.Analysising the system of PHM of theimportant parts, it can get out of order because of continuous development and thecumulative result of damage. It supposes the system has two kinds of failure modes,safe-failure and danger-failure. By using the ion channel theory, it can establish themodel of the allocation of Spare parts and give the formula of the demand of Spareparts. The model is further extended for three set of States, work set, fault state setand the intermediate state set, it can describe the process based on Markov andSemi-Markov repairable Systems by using state aggregation, and give the formula ofthe allocation of the Spare parts and other related reliability index.Finally，On the basis of the technology of PHM, the dissertation establishes themodel of the assessment of Spare parts. The model can provide the decision-makingsupport of a theoretical basis by evaluating the model of assessment of Spare parts inorder to increase the probability of success of the system security tasks. Thedissertation assumes that parts are damaged in the period specified, and establish themodel of the assessment of Spare parts for the non-repairable systems and repairsystems by using the theory of the update process and queuing theory.At the sametime, it can give the assessment of Spare parts when the life distribution of the Sparesparts has exponential, normal, Weibull, gamma distribution.The research of this dissertation will have more potential applications, whichmay promote the developments of reliability in theory and engineering, also thisresearch will play an important role on raising availability of systems and reducingthe life cycle costs of systems greatly. On the other hand, some research results in thisproject may be used in other areas of management science and engineering, theresearch may also promote the impact on academia in reliability field of our countryin the world.