0
TECHNICAL PAPERS

Design Loads Used for Direct Strength Assessment of Merchant Ship Structures

[+] Author and Article Information
Tingyao Zhu1

Nippon Kaiji Kyokai (ClassNK), Research Institute, 1-8-3, Ohnodai, Midori-Ku, Chiba 267-0056, Japanzhu@classnk.or.jp

Toshiyuki Shigemi

Nippon Kaiji Kyokai (ClassNK), Research Institute, 1-8-3, Ohnodai, Midori-Ku, Chiba 267-0056, Japan

1

Corresponding author.

J. Offshore Mech. Arct. Eng 129(2), 120-130 (Sep 04, 2006) (11 pages) doi:10.1115/1.2426985 History: Received March 23, 2005; Revised September 04, 2006

This paper summarizes the results of extensive research on the design loads used for strength assessment of merchant ship structures such as tankers, bulk carriers, and container ships. The main aim of the research was to develop practical estimation methods of design loads having rational technical backgrounds acting on primary structural members of tankers, bulk carriers, and container ships. During this study we will do the following. (1) The design sea states that closely resemble the actual sea states which are considered as the most severe for hull structures are proposed. (2) The practical estimation methods of the design sea states are proposed by parametric studies using the results of series calculation of representative merchant ships. (3) The practical estimation methods of design regular waves resulting in the same level of stresses as that induced in irregular waves under the design sea states are proposed. (4) The practical estimation methods of the design loads such as ship motions, accelerations, hull-girder bending moments, and hydrodynamic pressures that are induced under design regular waves are briefly introduced. The findings in this study have been summarized and implemented in the new design standards for tanker, bulk carrier, and container ship structures (“Guidelines for Tanker Structures,” 2001, Nippon Kaiji Kyokai; “Guidelines for Bulk Carrier Structures,” 2002, Nippon Kaiji Kyokai; “Guidelines for Container Carrier Structures,” 2003, Nippon Kaiji Kyokai).

Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 1

FE models used for direct structural analysis

Grahic Jump Location
Figure 2

Examples of critical structural members where stresses are examined

Grahic Jump Location
Figure 3

Dominant sea states in terms of mean wave period and wave encountering angle

Grahic Jump Location
Figure 4

Significant wave heights in the short-term sea states resulting in the same level of response with the long-term prediction at 10−8 (the relation between wave length and significant wave height)

Grahic Jump Location
Figure 5

Comparisons of the mean wave periods obtained by the direct load analyses and those obtained by the simplified formulas for tankers, bulk carriers, and container ships

Grahic Jump Location
Figure 6

Comparisons of the significant wave heights obtained by the direct load analyses and those obtained by the simplified formulas for tankers, bulk carriers, and container ships

Grahic Jump Location
Figure 8

Coefficient C4 corresponding to the design regular waves determined by each dominant load

Grahic Jump Location
Figure 9

Standard deviations of rolling motion in waves of different wave heights obtained by model tests and numerical calculation

Grahic Jump Location
Figure 10

Comparisons of the pitch, roll, and acceleration at the center of gravity of the ship due to heave obtained by the direct load analyses and those obtained by the simplified formulas for the full load condition

Grahic Jump Location
Figure 11

Comparisons of the pressure distributions obtained by long-term prediction and those obtained by the simplified formulas for full load condition corresponding the double-hull VLCC, the Cape-size bulk carrier, and the post-Panamax container ship

Grahic Jump Location
Figure 12

Four different kinds of the design loads (external and internal dynamic pressures) in regular design waves for the double-hull VLCC

Grahic Jump Location
Figure 13

Hold FE models used for structural analysis under design loads determined by the simplified formulas

Grahic Jump Location
Figure 15

Comparisons of the stresses obtained by long term prediction and those obtained by the simplified method

Grahic Jump Location
Figure 14

Locations of the primary structural members used in the comparative study

Grahic Jump Location
Figure 7

Comparisons of the wave lengths of the design regular waves obtained by the direct load analyses and those obtained by the simplified formulas for tankers, bulk carriers, and container ships

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In