Numéro : 2442 - Year : 2004
Fatigue of tanker structures return experience
Michel HUTHER, BUREAU VERITAS - Division Marine – Paris (France)
Alexis CARAUX, BUREAU VERITAS - Division Marine – Paris (France)
Guy CESARINE, BUREAU VERITAS - Division Marine – Paris (France)
Cristian BRAN, BUREAU VERITAS - Division Marine – Paris (France)
Fatigue cracking of structural details has become from some years ago a predominant mode of failure in ships. Since the years 70s verification methods of the fatigue resistance for a given life time have been developed, but there is very few comparisons of results obtained by these methods and fatigue cracks observations on ships. Some recent cases of cracks in tankers and FPSO allowed to perform such studies which process and results are presented, for selected typical details covering the different stress field configurations. The actual rule method is found correct to evaluate the life time of welded joints with stress ranges mainly in tension. At the opposite, this method was found possibly erroneous for stress ranges mainly in compression and for non welded details with compression. A complementary method has been developed to provide correct results in all cases. The application provide good results although improvements are always necessary.