Time-dependent reliability assessment of ship structures under progressive and shock deteriorations

The aim of this paper is to provide a rational reliability assessment of ship structures under multiple hazards during their lifetime. These hazards cause both progressive and shock deteriorations of structural performance. Time-dependent estimation of structural reliability must consider multiple failure modes. In this paper, the safety margins under progressive and shock hazards are evaluated separately for the associated failure modes. Considering the cumulative effect of multiple hazards during the lifetime, probabilistic structural deterioration process is represented by using cumulative-time approach. To present the multi-hazard analysis, corrosion and extreme lateral pressure are adopted as progressive and shock type hazards, respectively. Failure modes of buckling and permanent set are considered for safety and serviceability of a ship structure component. Side shell plating structure in a tanker is used to illustrate the evaluation of lifetime structural performance deterioration in multi-hazard environment.