Extreme Value Predictions using Monte Carlo Simulations with Artificially Increased Wave Height

摘要

For non-linear processes a good estimate for the mean out-crossing rate can be found using the First Order Reliability Method (FORM). An interesting property with the FORM solution is that the associated reliability index is inversely proportional to the significant wave height. The present paper investigates whether this property also holds for Monte Carlo simulations. If so, Monte Carlo simulations could conveniently be performed with a larger significant wave height than actually required for design, reducing significantly the necessary length of the time domain simulations. The mean out-crossing rate thus obtained can then afterwards be scaled down to the actual significant wave height using this property. In the present paper the generality of this relation is investigated, considering the probability that the design wave-induced hogging bending moment in a container ship is exceeded, accounting for both non-linear wave load effects (bow flare slamming) and hull flexibility (whipping vibrations).