Maintained ship hull xcgirxcder ultimate strength reliability considering corrosion and fatigue

The purpose of this paper is to propose a methodology to assess the time-variant ultimate strength of ship hull girder under the degradations of corrosion and fatigue. The effects of fatigue cracks on the tensile and compressive residual ultimate strength of stiffened panels and unstiffened plates are analyzed by an FE method. Based on FE analysis results, some empirical formulae are provided for effective calculation of the compressive or tensile ultimate strength of cracked or intact unstiffened plates or stiffened panels. A non-linear corrosion model is used to determine the corrosion rate of plates, webs and flanges, respectively. The effects of inspection and repair are taken into account. A minimum net thickness rule is used to determine repair policies. A procedure is proposed to determine the maximum allowable corrosion thicknesses of different parts of the hull cross section. The procedure developed is illustrated by application to a tanker. For a given set of inspection and repair criteria, the ultimate bending moment and reliability as a function of ship age is predicted.

[1]  Jeom Kee Paik,et al.  Probabilistic corrosion rate estimation model for longitudinal strength members of bulk carriers , 1998 .

[2]  Tetsuya Yao,et al.  ULTIMATE LONGITUDINAL STRENGTH OF A BULK CARRIER , 1993 .

[3]  Jeom Kee Paik,et al.  Ship hull ultimate strength reliability considering corrosion , 1998 .

[4]  Torgeir Moan,et al.  Estimation of nonlinear long-term extremes of hull girder loads in ships , 2000 .

[5]  Alaa E. Mansour,et al.  A simple formulation for predicting the ultimate strength of ships , 1995 .

[6]  Preben Terndrup Pedersen,et al.  Strength of ship plates under combined loading , 2002 .

[7]  J. K. Paik,et al.  An Empirical Formulation for Predicting the Ultimate Compressive Strength of Plates and Stiffened Plates , 1996 .

[8]  Weicheng Cui,et al.  Effect of corrosion models on the time-dependent reliability of steel plated elements , 2003 .

[9]  C. Guedes Soares,et al.  Reliability of maintained ship hull girders subjected to corrosion and fatigue , 1998 .

[10]  C. Guedes Soares,et al.  Fatigue reliability of the ship hull girder , 1996 .

[11]  Paul H. Wirsching,et al.  Reliability with respect to ultimate strength of a corroding ship hull , 1997 .

[12]  C. Guedes Soares,et al.  Reliability of maintained ship hulls subjected to corrosion and fatigue under combined loading , 1996 .

[13]  J K Paik,et al.  Ultimate strength of ageing ships , 2002 .

[14]  C. Guedes Soares,et al.  Reliability of Corrosion Protected and Maintained Ship Hulls Subjected to Corrosion and Fatigue , 1999 .

[15]  Cui Wei-cheng.  A Simplified Analytical Method to Predict the Ultimate Strength of Unstiffened Plates Under Combined Loading Including Edge Shear , 2003 .

[16]  Akira Nitta,et al.  Basis of IACS unified longitudinal strength standard , 1992 .

[17]  Tetsuya Yao,et al.  Hull girder strength , 2003 .