Original scientific paper
https://doi.org/10.21278/brod68206
AN ENHANCED METHOD FOR EXTREME LOADS ANALYSIS
Francesco Mauro
orcid.org/0000-0003-3471-9411
; Università degli Studi di Trieste
Radoslav Nabergoj
orcid.org/0000-0003-2317-484X
; NASDIS PDS, Industrijska Cesta 2E, 6310 Izola, Slovenija
Abstract
The analysis of time records, coming from seakeeping experiments in irregular waves, is used to determine the occurrence of extreme events. The common procedure used for data analysis is to assume that the statistics of record’s peaks is following two or three parameters Weibull distribution. For particularly severe sea states it can happen that the peaks assume a multi-modal distribution. In this case, a Weibull distribution is not suitable, also in the three parameters form, to reproduce the peaks population. That means some errors in the estimate of the extreme loads may occur, affecting consequently the vessel/structure design process. To overcome this source of error it is possible to use multi-modal distributions, or to change the peaks extraction technique, adopting a certain threshold. By using this second approach data should be fitted according to a Generalised Pareto distribution. Based on this theory, a data analysis procedure including the threshold selection is here proposed and tested on a set of time records coming from seakeeping model-scale experiments. The results are then compared with the standard Weibull approach.
Keywords
Generalised Pareto Distribution; Weibull Distribution; Extreme Value Theory
Hrčak ID:
177415
URI
Publication date:
30.6.2017.
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