Comparative Study on Ultimate Strength of Stiffened Plates in the In-Service Vessels

초록

This paper deals with two items: first, distributions of slenderness ratios of stiffened plates in the in-service ships which include dimension and material variables of stiffened plates, and, second, comparison of ultimate strengths of stiffened plates. The investigated vessels consist of 59 tankers, 46 bulkers, 28 product carriers, 15 container carriers, and 8 multi-purpose vessels. The vessel sizes are ranged from handymax to VLCC(max. 370K DWT) for tankers and most of investigated vessels are larger than Suezmax class. Parameters of normal distributions of the slenderness ratios are suggested and practical design ranges of the slenderness ratios are also graphically presented. The comparison of the ultimate strengths of the stiffened plates, based on various simplified formulas and FEA (finite element analysis), is presented. For the implementation of the Smith method for hull girder strength estimation, as well, comparisons of post-ultimate strength behaviors are proposed. It is proved that CSR for bulker shows most conservative results with respect to the ultimate strengths and post-ultimate strengths.