Research On Overall Longitudinal Strength Reliability Of Military Vessel

The dissertation is centralized on reliability analysis of overall longitudinal strength of hull. Because increasingly conventional fixed value method can't adapt to evaluation demands of engineering construction which expect structure safety index to be much more exact, it is very important to carry through reliability research on overall longitudinal strength of hull and evaluate change of hull structure reliability during enlistment, which help to set up corresponding scheme to ensure safety of hull structure and settle theoretical foundation only to establish reliability analysis specifications of overall longitudinal strength of hull.Study on reliability of overall longitudinal strength of hull based on structure reliability theory can be divided into two parts. The first one is to make certain probability distributions of random variables in limit state function characterizing demand and capacity of overall longitudinal strength invalidation. The second one is to calculate structure invalidation probability and reliability index to evaluate overall longitudinal strength of hull.Thus, considering yield invalidation mode of overall longitudinal strength of hull, a feasible reliability analysis scheme of overall longitudinal strength of hull is presented as following:As for the random variables characterizing demand of overall longitudinal strength invalidation, a method combining numerical value simulation and conventional still water bending moment calculating measure is used to make sure statistical characteristic of still water bending moment. Besides, prediction modal of probability distribution of wave bending moment is established based on a numerical value calculating method. As for the random variables characterizing capacity of overall longitudinal strength invalidation, an improved Rosenbluthe method is introduced to calculate statistical characteristics of minimum middle transverse section module, while probability distribution of material yield limit is ascertained by concerning research.Search adaptive Monte Carlo importance complete sampling method is presented to carry out reliability analysis of overall longitudinal strength of hull, which can give invalidation probability with faster convergence speed by balancing precision and speed of arithmetic validly only to enhance efficiency of Monte Carlo method. Citing certain warship as example, reliability evaluation of overall longitudinal strength is carried out by using both search adaptive Monte Carlo importance complete sampling method and JC method, while concerning analysis is made based on evaluation results.