Fig. 1 Existing data by age and engine type
By arranging the failure data of 98 propulsion ship engine categorized into 5 types according to their lifetimes, we got the failure rate data for the approximate total life cycle of 31 years (It is expressed as approximate because it is not based on the total life data of each ship, but is the data of the total life created by combining parts). The data only include maintenance records from the military direct maintenance workshop. After the construction, the initial repair of the shipyard(warranty repair) was not included in the data. Also, data may not be entered into the management system for other reasons. Therefore, it can be said that the failure data of the part corresponding to the initial part after constructing is reflected less than actual.
3.2. Model and process
Naval ship engines applied in the proposed model are classified as Fig. 2. The ship engine (layer 3) of each ship belongs to the same engine type (layer 2), and 5 types belong to the entire engine archetype (layer 1).