Generate the Ultimate Longitudinal Strength of Damaged Container Ship Considering Random Geometric Properties Under Combined Bending Moment

2021 ◽  
pp. 495-501
Author(s):  
Huynh Van-Vu ◽  
Cho Sang-Rai
Keyword(s):  
Bending Moment ◽  
Container Ship ◽  
Geometric Properties ◽  
Longitudinal Strength

Calculation of Horizontal Sectional Loads and Torsional Moment

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Vladimir Shigunov ◽  
Alexander von Graefe ◽  
Ould el Moctar
Keyword(s):  
Free Surface ◽  
Shear Force ◽  
Three Dimensional ◽  
Bending Moment ◽  
Green Functions ◽  
Container Ship ◽  
Horizontal Shear ◽  
Torsional Moment ◽  
Oblique Waves ◽  
Rankine Source

Horizontal sectional loads (horizontal shear force and horizontal bending moment) and torsional moment are more difficult to predict with potential flow methods than vertical loads, especially in stern-quartering waves. Accurate computation of torsional moment is especially important for large modern container ships. The three-dimensional (3D) seakeeping code GL Rankine has been applied previously to the computation of vertical loads in head, following and oblique waves; this paper addresses horizontal loads and torsional moment in oblique waves at various forward speeds for a modern container ship. The results obtained with the Rankine source-patch method are compared with the computations using zero-speed free-surface Green functions and with model experiments.

Strength of a Container Ship in Extreme Waves Obtained by Nonlinear Hydroelastoplasticity Dynamic Analysis and Finite Element Modeling

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Weiqin Liu ◽  
Xuemin Song ◽  
Weiguo Wu ◽  
Katsuyuki Suzuki
Keyword(s):  
Finite Element ◽  
Nonlinear Dynamic ◽  
Structural Response ◽  
Bending Moment ◽  
Dynamic Responses ◽  
Container Ship ◽  
Extreme Waves ◽  
Wave Models ◽  
The One ◽  
The Time Domain

Extreme waves have caused a lot of ship accidents and casualties. In this paper, a two-dimensional (2D) hydroelastoplasticity method is proposed to study the nonlinear dynamic responses of a container ship in extreme waves. On the one hand, the traditional ultimate strength evaluation is mainly performed using a quasi-static assumption without considering the dynamic wave effect. On the other hand, the dynamic response of a ship induced by a wave is studied based on hydroelasticity theory, which means the ship structural response to large waves is linear. Therefore, a 2D hydroelastoplasticity method that accounts for the coupling between the time-domain wave and ship beam for nonlinear vertical bending moment (VBM) is proposed. In addition, a nonlinear dynamic finite element method (FEM) is also applied for the nonlinear VBM of ship beam. The computational results of the FEM, including the nonlinear VBM and deformational angle, are compared with the results of the 2D hydroelastoplasticity and hydroelasticity. A number of numerical extreme wave models are selected for computations of hydroelasticity-plasticity, hydroelasticity, and FEM. A difference is observed between the nonlinear VBM calculated by FEM and linear VBM calculated by hydroelasticity, and conclusions are drawn.

scholarly journals Study on Longitudinal Ship Strength Caused by the Placement of Beams and Girders on Upper Deck Side

2018 ◽  
Vol 1 (2) ◽  
pp. 74-80
Author(s):  
Andi Ardianti ◽  
Andi Mursid Nugraha ◽  
Ganding Sitepu ◽  
Hamzah Hamzah ◽  
Ade Khantari ◽  
...  
Keyword(s):  
Structural Response ◽  
Bending Moment ◽  
Ship Model ◽  
Upper Deck ◽  
Deck Plate ◽  
Longitudinal Strength ◽  
Moment Load ◽  
Vertical Bending Moment ◽  
Beams And Girders ◽  
Classification Society

The location of the beam and the deck girder of the ship can be effect on it is strength especially for the longitudinal strength due to the vertical wave bending moment. The objective of this study is to know the structural response of the ship due to vertical bending moment load on hogging and sagging conditions. The analysis is carried out by using Finite Element Method so-called ANSYSTM. The results shows that the stress occurring on the ship model with deck beam above the deck plate is larger than the ship model with deck beam under the deck plate. When the load with the variated of 0.2 x moment of vertical moment load, there is an increase of stress that occurs both on the deck area about 12% while on the bottom area about 0.98%. This study also conducted a stress comparison by using analysis methods with analytical methods. The results show that by the Stress differences that occur in the structure with the longitudinal deck beam and deck girder above are 14.1% on the deck and 7.1 on the bottom. Whereas in the structure with deck longitudinal deck eam and deck girder under there is a difference of 5.7% on the deck area and 3.5% in the bottom area of the ship. The stress that occur in both models have a difference that is not too far away and still under the permisible stress by the classification society so that both can be applied to the construction of a tanker.

An Advanced Salvage Method for Damaged Ship Structures

2021 ◽  
Author(s):  
Alessandro La Ferlita ◽  
Helge Rathje ◽  
Thomas Lindemann ◽  
Patrick Kaeding ◽  
Robert Bronsart
Keyword(s):  
Decision Making ◽  
Environmental Conditions ◽  
Bending Moment ◽  
Decision Making Process ◽  
Iterative Approach ◽  
Short Term ◽  
Smith Method ◽  
Longitudinal Strength ◽  
Wave Induced ◽  
Damaged Ship

An advanced salvage method is proposed for damaged ships to ensure a short-term decision-making process for a safe ocean towage to the repair yard. The residual longitudinal strength must be greater than the sum of the still water and the maximum vertical wave bending moment. The ultimate bending moment is determined numerically for a container vessel by using an incremental iterative approach (Smith method) and wave-induced loads are predicted by means of hydrodynamic analyses. Successful applicability of the advanced salvage method is demonstrated for a damaged container vessel, which was towed from La Libertad, Ecuador, via Panama to the repair yard in Zhoushan, China, in restricted environmental conditions.

A Guide for the Ultimate Longitudinal Strength Assessment of Ships

2004 ◽  
Vol 41 (03) ◽  
pp. 122-139
Author(s):  
Jeom Kee Paik
Keyword(s):  
Progressive Collapse ◽  
Limit State ◽  
Bending Moment ◽  
Ship Hull ◽  
Safety Measure ◽  
Ultimate Limit State ◽  
Ship Hulls ◽  
Collapse Analysis ◽  
Longitudinal Strength ◽  
Progressive Collapse Analysis

The aim of the present paper is to establish a practical guide for the ultimate longitudinal strength assessment of ships. The ultimate hull girder strength of a ship hull can be calculated using either the progressive collapse analysis method or closed-form design formulas. In the present paper, both the progressive collapse analysis method and the design formulas are presented. A comparison between the progressive collapse analysis results and the design formula solutions for merchant cargo ship hulls is undertaken. The total design (extreme) bending moment of a ship hull is estimated as the sum of the still-water and wave-induced bending moment components as usual. The safety measure of a ship hull is then defined as a ratio of the ultimate longitudinal strength to the total design bending moment. The developed guidelines are applied to safety measure calculations of merchant ship hulls with respect to hull girder collapse. It is concluded that the guidance and insights developed from the present study will be very useful for the ultimate limit state design of newly built ships as well as the safety measure calculations of existing ship hulls. The essence of the proposed guide shall form ISO code 18072-2: Ships and Marine Technology— Ship Structures—Part 2: Requirements of Their Ultimate Limit State Assessment.

Calculation of Horizontal Sectional Loads and Torsional Moment

2014 ◽  
Author(s):  
Vladimir Shigunov ◽  
Alexander von Graefe ◽  
Ould el Moctar
Keyword(s):  
Potential Flow ◽  
Shear Force ◽  
Bending Moment ◽  
Green Functions ◽  
Container Ship ◽  
Horizontal Shear ◽  
Torsional Moment ◽  
Oblique Waves ◽  
Model Experiments ◽  
Rankine Source

Horizontal sectional loads (horizontal shear force force and horizontal bending moment) and torsional moment are more difficult to predict with potential flow methods than vertical loads, especially in stern-quartering waves. Accurate computation of torsional moment is especially important for large modern container ships. The 3D seakeeping code GL Rankine has been applied previously to the computation of vertical loads in head, following and oblique waves; this paper addresses horizontal loads and torsional moment in oblique waves at various forward speeds for a modern container ship. The results obtained with the Rankine source-patch method are compared with the computations using zero-speed wave Green functions and model experiments.

Time Domain Comparison With Experiments for Ship Motions and Structural Loads on a Container Ship in Abnormal Waves

2011 ◽  
Author(s):  
Suresh Rajendran ◽  
Nuno Fonseca ◽  
C. Guedes Soares ◽  
Gu¨nther F. Clauss ◽  
Marco Klein
Keyword(s):  
Time Domain ◽  
Bending Moment ◽  
Green Water ◽  
Ship Motions ◽  
Container Ship ◽  
Wave Elevation ◽  
Strip Theory ◽  
The Time Domain ◽  
Vertical Bending Moment ◽  
Comparison With Experiments

The paper presents experimental results from model tests with a containership advancing in abnormal wave conditions and comparisons with numerical simulations. A nonlinear time domain method based on strip theory is used for the calculation of vertical ship responses induced by abnormal waves. This code combines the linear diffraction and radiation forces with dominant nonlinear forces associated with vertical response arising from Froude-Krylov forces, hydrostatic forces and shipping of green water. The time domain simulations are compared directly with experimental records from tests with a model of a container ship in deterministic waves for a range of Froude numbers. Extreme sea conditions were replicated by the reproduction of realistic abnormal waves like the New Year Wave and abnormal wave from North Alwyn. Head sea condition is considered and the comparisons include the wave elevation, the vertical motions of the ship and the vertical bending moment at midship.

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