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theses

This research pertains to reliability and maintenance for a system with individually repairable components degrading as gamma processes. Life and expenses of the system are the two main factors considered in this research by analyzing the reliability and cost rate functions. The main difference of this current study from previous system reliability research is the system model has component degradation, individual component repair and different component histories. As the economy develops at an amazing speed in recent years, people care more about their experiences while doing or using something rather than basic functionality. For instance, customers concern more and more about their satisfaction with the products they buy and the services they get, so companies, producers and many other institutions attach great importance to reliability and quality of products. Moreover, when people travel, they care more about their safety and comfort. Therefore, reliability becomes increasingly more important, and it exists everywhere in our life. High reliability design practices can make products reliable and ensure their quality, their safety, their life cycles and the like. Although system reliability problems have been studied and divided into many smaller categories and these categories also have been subdivided into even smaller parts. These problems have been studied for many years by different researchers, and quite a few studies are very complex when applied to actual systems. In general, not all of them are practical or can be solved efficiently. Conversely, they are beneficial for researchers to do further research to understand the behavior of complex systems. Because of their complexity, many models and situations in those studies are not often applied for real engineering processes. Therefore, this research aims to build a practical model widely applied to real situations, factories and industries. The reliability of many products is not always studied in detail because of their low price. For some products, such as batteries and tires which are non-repairable, engineers and products owners replace them simply because they are non-repairable. However, most industrial equipments, such as railroad tracks, gas pipelines and huge mechanical facilities, are repairable, and it is economical to repair the failed components rather than to discard the whole system. Meanwhile, rebuilding a new system is very costly. Taking all these factors into consideration, this research aims to build a model of a system with individually repairable components, each of them degrading as a gamma process. The component degradation paths can also be probabilistically dependent due to shared exposure to shocks. Studying the reliability and cost rate function of such systems can lead us to obtain the optimal maintenance policy. The results and conclusions of this study can be widely used in practical engineering work in future research.

ETD_9495

M.S.

Includes bibliographical references

by Jingyu Chen

doi:10.7282/t3-3z01-py07

ETD graduate

The author owns the copyright to this work.