Ship Hull's Fatigue Analysis Based On JBP Rules

Since the date of April the first, 2006, the common rules of structure including JTP and JBP which had been put into practice all over the world was a marker that the world's shipbuilding industry had entered a new era. So, research on these new rules will have far-reaching and great significance.Bulk carrier, which has the second largest number after the tanker in the field of international shipping, its loading conditions are very complicated. Moreover, in order to adapt to the development trend of the freight capacity, the scale of bulk carriers are having the trend to increase. From the survey on recent years' maritime accident, we find that fatigue failure is one of the main modes of the ship structure's damage. Therefore, research on fatigue has become the extremely important part of the risk assessment for bulk carrier.In this paper, based on the JBP rules and the theory of fatigue, we carry out in-depth discussions about the methods of fatigue assessment in the new rules. At the same time, we take a practical bulk carrier for example and adapt two different methods to carry out fatigue assessment calculating. By comparing with the different results, we intend to be familiar with the new rules and find the best way for fatigue checking.Firstly, we expound the basic knowledge of fatigue theory, mainly providing two methods of assessment's explanation, a simple comparison of the two methods and a detailed briefing on the S-N curve method.Secondly, this paper also introduces the detailed calculation method about fatigue assessment in JBP rules. There are two methods for hotspot stress calculation: the finite element method and the empirical formula method. In the empirical formula method, according to the different positions of components, the formula we used is also different. We can obtain the result of incision stress by calculating the hotspot stress, then based on the principle of S-N curve, we carry out the fatigue assessment analysis on ship hull.Next, by selecting a suitable bulk carrier, we use the method mentioned above to carry through the fatigue assessment and compare the results simply.Finally, we compare the fatigue assessment method in JBP rules with the one in JTP rules in order to find out the similarities and differences of the fatigue assessment method in these two rules.