船舶結構通常使用鋼材做為船體，然而鋼材受不斷變化的波浪與嚴苛的環境下極易發生疲勞與腐蝕現象。本文旨在探討船舶因疲勞所產生的結構破壞與合併腐蝕與疲勞裂縫兩效應作用下對船舶的破壞後進行維修之船舶結構可靠度分析。文中將疲勞裂縫之可靠度分析分為兩個破壞模式來討論，首先考慮已具有初始裂縫之疲勞裂縫成長的可靠度，其次為在初始裂縫未發生前之疲勞可靠度。同樣地腐蝕過程亦可分為二個層面來看，第一個過程為塗裝保護仍為有效過程，第二個階段為塗層開始失效並開始發生腐蝕的過程。由於發生初始裂縫的時間與塗層失效的時間可視為隨機變數，故船舶結構之可靠度就必須考慮裂縫初始時與塗層失效之機率下的條件可靠度。最後依據上述兩效應的合併條件，來求得船體結構的可靠度或失效機率以利於船舶維修之方便。

In general the structure of large ships are made of steel, the corrosion and fatigue of the steel may occur due to the waves and harsh environment.
The purpose of this study is to assess fatigue translate into structure failure and reliability analysis on the structure of maintained ships after failure under the effect of combined corrosion and fatigue crack.
The reliability analysis of fatigue crack is broken down into two failure model, for one is concerning the reliability of the possession of initial crack in fatigue crack growth, the other is regarding fatigue reliability before initial crack. The process of corrosion also can be separated into two stages：the first is the time during which the coating protection is effective, the second starts when the effectiveness of the coating is ineffectual and general corrosion starts occurring. Since the time to crack initiation and the termination of coating life are random variables, and thus the reliability of initial crack and the probability of coating failure are taken into consideration when it comes to the reliability of ship’s structure. Finally, based on the combined effects of fatigue and corrosion, the reliability or the probability of failure of a bulk carrier is studied to make the improvements on repairing.

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