Fatigue Assessment and Extreme Response Prediction of Ship Structures

摘要: In this thesis, a simplified narrow-band approximation model is proposed to estimate fatigue damage of ship structures, and an efficient method for extreme response predictions also developed using upcrossing spectrums responses. The includes two main parameters, significant stress range hs zero frequency fz. The first parameter assumed be proportional wave height Hs through factor C, derived from linear hydrodynamic theory. value C depends on the mission conditions. approximated by encountered frequency, where period Tz deduced explicit function Hs. validated “accurate” rainflow with less than 10% discrepancy. uncertainties life are studied safety index, employing model. It shown that index computed agrees well measurements. With respect fact responses non-Gaussian, Laplace Moving Average (LMA) transformed Gaussian approach non-Gaussian responses. adopted computation spectrums. then estimated standard deviation, skewness kurtosis needed compute agree those engineering measured