engleski

Extreme Response Assessment using Genetic Algorithm Approach

An important parameter regarding operability and structural safety of ships and offshore objects is its extreme response at heavy environmental conditions. One of the most critical features of the design process is the estimation of the worst condition to which a given structure is likely to be exposed in its lifetime, and in particular the prediction of a characteristics value which is associated with the certain probability of nonexceedance in that time. Two major statistical issues can be distinguished in the procedure of wave extreme prediction. The first issue is that predicted extreme values must be based on data collected in relatively short time. The second issue is extrapolation of the observed data into its extreme region, typically lying well beyond from even the most extreme available observation. The process of extrapolation plays a fundamental role in this area of analysis and therefore it is essential to fit empirically a convenient probability distribution that describes the available data as closely as possible. Estimation of extreme values probability distribution parameters by genetic algorithm is applied to improve the methodology of extreme sea state prediction. Illustrative applications of the method are given for a ship of approximately 135 m length response on North Atlantic sea environment. The results are presented as crest height maximum values occurring with a given probability or in a design storm that has a specified return period. The time series of ship response at most severe storm in 50 years are given.

Design Sea State; Extreme Response; Genetic Algorithm

nije evidentirano