Fatigue And Ultimate Strength Analysis Based On IACS CSR For Bulk Carriers

Fatigue and ultimate strength are important factors for the safety of naval and ocean structure. It has been a vital research field for a long time. But there are many differences in the Classification Society rules, even for the same ship, the fatigue results are different according to these rules. IACS Common Structural Rules for Bulk Carriers (CSR) has gone into effect at 1^st April 2006. It specified the load, loading condition, FE model and the fatigue assessment criteria. The fatigue life and corrosion additions of ship structure were increased obviously.The hull gird ultimate strength has attracted the attention of the international ship building and ocean engineering field in recent 20 years. The hull gird ultimate strength check has been added to the classification society rules. The CSR required that the hull gird ultimate strength should be done for the ship equal to or greater than 150m in length.This paper is mainly about the fatigue assessment and ultimate strength check of ship structure according to the CSR. The main contents are as follows:1) Introduce the basic principle and assessment procedure of ship structure fatigue strength based on the equal design wave approach (EDW). The dominant load parameter and the selection of design wave in terms of dominant load parameters are dissertated.2) The CSR fatigue assessment procedure, load, loading condition and cumulative fatigue damage D were introduced in the paper. The theory background of the CSR fatigue assessment were researched based on the equal design wave approach.3) The hot spot and stiffener stress assessment of 210 000t bulk carrier were done according to the CSR, and compared to the result of CCS rules.4) The hull gird ultimate strength of 210 000t bulk carrier was checked by the use of Mars2000 that was recommended by IACS based on the incremental-iterative approach, and compared to the result of single step method.