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Marine and offshore structures are subjected to fatigue loadings primarily due to the action of seawater waves and the sea environment in general. The load cycles in such an environment can be in the order of a million cycles per year. Fatigue failures in these structures can take place at sites of high stress concentration that can be classified by two major categories: baseplate and weldments. The former includes locations of high stress concentration such as openings, sharp re‐entry corners, and plate edges. In general, the mechanisms behind these failures are described by the general approaches to fatigue life prediction as discussed in this paper. There are two major approaches for predicting fatigue life: (1) the S‐N curve approach and (2) the fracture mechanics (FM) approach. The S‐N curve approach is based on experimental measurement of fatigue life in terms of cycles to failure for different loading levels and specimen geometries, while the fracture mechanics (FM) approach is based on the existence of an initial crack and subsequent crack propagation under cyclic load. The objective of this paper is to develop reliability‐based methods for determining the fatigue life of structural details associated with conventional displacement type surface monohull ships based on the S‐N approach and on the assumption that fatigue damage accumulation is a linear phenomenon (i.e., that follows Miner's rule). The methods are also based on structural reliability theory and can be applied either in direct reliability‐based design or in a load and resistance factor design (LRFD) format. The resulting design methods are referred to as the reliability‐based design approach for fatigue of marine structures. These design methods were developed according to the following requirements: (1) spectral analysis of wave induced loads, (2) use of conventional fatigue design codes, (3) nominal strength and load values, and (4) achieving target reliability levels. The first‐order reliability method (FORM) was used to perform reliability assessments and to develop the partial safety factors (PSFs) for fatigue limit state equations.

Experiments to evaluate and validate processes of engineering and science are particularly important when the phenomena under investigation may be studied empirically, as can metal fatigue or medical injection dosages. Sometimes during an experiment, individual tests in a series are not completed, or must be suspended or interrupted, or are somehow damaged. Such test points are referred to as "suspended," or "censored points," or in the case of metal fatigue are simply called runouts. All these names refer to test specimens that do not fail under the same conditions as do other specimens or data points. In reliability and biometry, runout data are termed Type I censored observations. Inclusion of runouts in data analysis and interpretation can be problematic, and such ad hoc approaches as ignoring the runout observation or treating it as a failure can significantly affect estimation. Even when data are plotted and represented by a mathematical function utilizing least squares analysis to minimize data scatter about the "best fit" function, runouts and censored observations cause estimation problems because they cannot be incorporated directly into a leastsquares analysis procedure. This paper offers a methodology to help alleviate the problems presented by runouts and censored data. The methodology handles runouts and censored data by employing the maximum likelihood estimation (MLE) method to incorporate the censored data properly. The methodology is illustrated with an example problem.