Ultimate Limit State Function and Its Fitting Method of Damaged Ship under Combined Loads

Zhu, Zhiyao; Ren, Huilong; Li, Chenfeng; Zhou, Xueqian

doi:10.3390/jmse8020117

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…Xu [29] studied the buckling ultimate strength and proposed an analytical solution to the evaluation method of the hull ultimate strength under extreme wave loads. Zhu [30] studied the residual strength in damaged ships with the vertical and horizontal hull girder loads, as well as under combined stresses. The improved Smith method was used to calculate the residual load of the damaged ship, and the particle swarm optimization method was used to obtain the neutral axis of the damaged section.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Ship Hull Ultimate Strength under Fire Conditions: The Fire Smith Method Approach

Wu,

Du,

Yan

et al. 2023

JMSE

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This article presents the fire Smith method, which integrates the plate model and the Smith method, to analyze the impact of fire temperature and extent on the buckling strength of frigates. This investigation focused on the frigate’s buckling strength and how it is affected by a fire, achieved by modifying both deck temperature and area. Leveraging the principle of oxygen consumption, a coefficient “D” was introduced to account for fire temperature and region variations. This enabled the characterization of buckling strength under varying temperature and regional conditions through 64 simulations conducted on a frigate model. The outcomes revealed that the disparity between simulation results and the fire Smith method remained below 10%, establishing a solid basis for engineering assessment. As the high-temperature area decreased and necessitated less oxygen, the ultimate strength initiated a decline. However, upon reaching a certain threshold temperature, the ultimate strength stabilized. Conversely, expansive high-temperature zones caused a decline in ultimate strength, coupled with an increased oxygen requirement. Under consistent oxygen consumption conditions, the rate of ultimate strength reduction intensified. Consequently, these divergent characteristics of ultimate strength in various high-temperature areas underscored that minimizing the expansive fire high-temperature zones can significantly enhance the ship’s fire resistance, safeguarding its structural integrity.

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Section: Introductionmentioning

confidence: 99%

Assessment of Ship Hull Ultimate Strength under Fire Conditions: The Fire Smith Method Approach

Wu,

Du,

Yan

et al. 2023

JMSE

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“…Shahid [24] used the response surface method and the artificial neural network to fit the limit state function. Zhu et al [25] proposed the weighted piecewise fitting method for the limit state function. Paik et al [26] investigated the longitudinal strength of the as-built ultra-large containership under combined vertical bending and torsion, then fitted the limit state function with a nonlinear method and obtained the design load area.…”

Section: Introductionmentioning

confidence: 99%

Methods for Fitting the Limit State Function of the Residual Strength of Damaged Ships

Zhu

Ren

Wang

et al. 2022

JMSE

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The limit state function is important for the assessment of the longitudinal strength of damaged ships under combined bending moments in severe waves. As the limit state function cannot be obtained directly, the common approach is to calculate the results for the residual strength and approximate the limit state function by fitting, for which various methods have been proposed. In this study, four commonly used fitting methods are investigated: namely, the least-squares method, the moving least-squares method, the radial basis function neural network method, and the weighted piecewise fitting method. These fitting methods are adopted to fit the limit state functions of four typically sample distribution models as well as a damaged tanker and damaged bulk carrier. The residual strength of a damaged ship is obtained by an improved Smith method that accounts for the rotation of the neutral axis. Analysis of the results shows the accuracy of the linear least-squares method and nonlinear least-squares method, which are most commonly used by researchers, is relatively poor, while the weighted piecewise fitting method is the better choice for all investigated combined-bending conditions.

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“…Campanile et al [17,18] and Tekgoz et al [19] formulated this additional condition in a slightly different way and applied the extended Smith's method to assess the residual strength of various merchant ship types. Zhu et al [20] highlighted the need for robust solution procedures when the rotation of the neutral axis is considered in the incremental-iterative method. Fujikubo et al [5] derived an explicit expression for rotating the neutral axis within the pure-incremental method and examined its influence on the residual strength of damaged ships.…”

Section: Introductionmentioning

confidence: 99%

Progressive Collapse Analysis of Intact and Damaged Ships under Unsymmetrical Bending

Cerik

Choung

2020

JMSE

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This study examined the hull girder strength of intact and damaged ships by adopting the incremental-iterative method for progressive collapse analysis, which was extended to the general case of the unsymmetrical bending of beams with an arbitrary cross-section. The sources of an unsymmetrical loading, including rotation of the loading plane and section asymmetry caused by structural damage, are described. A fast and robust procedure is presented to determine the translation and rotation of the instantaneous neutral axis at each curvature increment when applying Smith’s progressive collapse analysis method. A series of analyses were conducted on a double hull VLCC and a bulk carrier, considering various loading plane angles and damage conditions. The decrease in ultimate strength and the influences of rotation of the instantaneous neutral axis and ship heeling are discussed. The proposed method can be used for a rapid and rational assessment of the hull girder strength under adverse conditions.

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Ultimate Limit State Function and Its Fitting Method of Damaged Ship under Combined Loads

Cited by 5 publications

References 13 publications

Assessment of Ship Hull Ultimate Strength under Fire Conditions: The Fire Smith Method Approach

Assessment of Ship Hull Ultimate Strength under Fire Conditions: The Fire Smith Method Approach

Methods for Fitting the Limit State Function of the Residual Strength of Damaged Ships

Progressive Collapse Analysis of Intact and Damaged Ships under Unsymmetrical Bending

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