Reliability Calculation Method Of Ship Longitudinal Ultimate Strength Under Extreme Sea Conditions

In the trend of full-sea-area and large-scale ship, extreme sea conditions need to pay attention when the ship is sailing. This made overall longitudinal strength of the ship put forward higher requirements. Reliability Analysis of Ship Longitudinal Ultimate Strength is an engineering concern, it is mainly related to the structural strength, load and reliability analysis. However, compared with the general method of reliability analysis, Selected structural structural strength under extreme conditions of random variables, load wave load in extreme conditions constitutes, reliability and its calculation method selected in consideration of ultimate strength and extreme loads and so is a topic worth exploring.Ship structural strength under extreme conditions, and the key is to chose the factors that have significant influence to ultimate longitudinal. Some research assess structural factors influence by sensitivity analysis, that identify the variables which significant influence Longitudinal Strength. And give the suggest value of the variables for the reliability analysis. Analysis of extreme loads in extreme sea wave conditions primarily consider the impact of extreme sea conditions for wave bending moment. Wave bending moment has obvious characteristics of random waves in extreme sea conditions, the scholars through research that the long-term wave obey Weibull distribution. However, these methods for the calculation of wave bending moment does not consider the impact of extreme sea conditions. In addition, the extreme sea wave conditions Ship Longitudinal ultimate strength reliability calculations, limit state function in two basic random variables, moment and wave structure of wave extreme sea conditions of ultimate strength does not obey simple distribution this makes the form of the limit state function is more complex, resulting in the reliability calculation methods commonly occur applicability.For the above problem, this paper selects the extreme wave conditions in the sea waves, slamming, deck flooded and sharply pitching which have a greater impact on the total vertical extreme wave bending. From the perspective of the ship sailing limits, taking account of the three types of extreme sea wave conditions. Then get extreme wave load under extreme wave sea conditions bigger than conventional wave moment extreme, experimental data show that the reference wave bending moment calculation method takes into account the extreme conditions of sea wave is more rational. By compare the reliability analysis method, give the suggestion that suit for the reliability analysis under extreme sea conditions.