Fatigue Strength Assessment Research On CSR And Design Against Fatigue Failure

Common Structural Rules for Bulk Carriers and Oil Tankers (CSR) which was developed by IACS has gone into effect on 1st April 2006 and unified the building standard of Bulk Carriers and Oil Tankers, but on fatigue assessment method there are still some differences between Bulk Carriers and Oil Tankers. The main content in this paper are as follows:1) The basic processes and the main contents of Fatigue strength assessment method in Common Structure Rules was summarized and dissertated. Author found that there is a relatively big difference between both fatigue assessment methods, mainly manifested in the fatigue load, loading condition, stress range composition, S-N curve selection, Weibull parameter selection, and so on.2) Emphasis analysis on following three critical points for fatigue assessment of CSR was carried out:(1) The fatigue load;(2) The selection of fatigue assessment locations;(3) The size of the finite element mesh and the hot spot stress extraction and interpolation method in hot spot stress method.3) According to the fatigue assessment of CSR, design against fatigue failure was studied and analyzed by the main factors that affect the fatigue strength of welded joints, hull structural details design methods and workmanship processes methods of improving fatigue performance. According to CSR TANKER rules, the fatigue analysis for a 110,000 DWT oil tanker was carried out, a series of good hull structural details were searched after and some reasonable suggestions about design against fatigue failure were given.