scholarly journals Review of Ultimate Strength Assessment of Ageing and Damaged Ship Structures

2020 ◽  
Author(s):  
M. Tekgoz ◽  
Y. Garbatov ◽  
C. Guedes Soares
Keyword(s):  
Ultimate Strength ◽  
Load Capacity ◽  
Fatigue Cracking ◽  
Ship Hull ◽  
Structural Behaviour ◽  
Ship Structures ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
The Impact ◽  
Damaged Ship

AbstractThe objective of this work is to provide an overview of the ultimate strength assessment of ageing and damaged ship structures in the last decades. Particular attention is paid to the ultimate strength of plates, stiffened panels, box girders, and entire ship hull structures subjected to corrosion degradation, fatigue cracking, and mechanical damage caused by accidental loading or impact. A discussion on the effect of the cyclic load on the plate rigidity, re-yielding, and ultimate load capacity on the ship hull girder is also part of the present study. Finally, some conclusions and discussions about potential future work are provided, identifying that more studies about the impact of corrosion degradation on the structural behaviour of the stiffened panels and the overall hull girders are needed. Studies related to the dynamic collapse behaviour of corroded and damaged ship structures under time-variant load also requires additional attention.

Buckling and Ultimate Strength Assessments of Ship Structures

2013 ◽  
Author(s):  
Shengming Zhang
Keyword(s):  
Ultimate Strength ◽  
Fe Analysis ◽  
Development Work ◽  
Ship Structures ◽  
Element Analysis ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Development History ◽  
Bulk Carriers ◽  
Oil Tankers

This paper presents buckling and ultimate strength assessment methods for ship structures. Buckling and collapsing analysis approaches for plates, stiffened panels and hull girders are described and their development history and employments in ship design assessments are reviewed and discussed. Examples using non-linear finite (FE) element analysis are given and comparisons between results obtained by formulae and FE analysis are carried out. Lloyd’s Register’s recent research and development work on ultimate strength and its applications to existing oil tankers and bulk carriers are also presented.

Ultimate Strength of Typical Stiffened Panels in Container Ships Under Localized Pitting Corrosion

2016 ◽  
Author(s):  
Jinju Cui ◽  
Deyu Wang ◽  
Ning Ma
Keyword(s):  
Life Cycle ◽  
Ultimate Strength ◽  
Pitting Corrosion ◽  
Load Capacity ◽  
Uniform Corrosion ◽  
Ship Structures ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Transverse Loads ◽  
Structural Capacity

In the life cycle of ships, corrosion exists and deteriorates ship structures, resulting in the degradation of ship structural capacity. Based on practical observations, non-uniform corrosion takes place instead of uniform corrosion which is adopted widely in design rules. So it is necessary to study the load capacity of ship structures under non-uniform corrosion. In this paper, the ultimate strength of typical bottom panels in container ships under localized pitting corrosion is studied by Nonlinear Finite Element Analysis (NFEA). The pitting corrosion is supposed to be of normally distributed circular shapes whose radius is in accordance with observational statistics. Different pitting corrosion densities with perforation in both the stiffener and panel plate are considered. Structural ultimate strengths under pitting corrosion are studied under longitudinal loads, transverse loads and combination of both, and the results are compared with that from equivalent uniform corrosion. Finally, the probabilistic characteristics of structural ultimate strength under pitting corrosion in life cycle are studied.

scholarly journals Collapse Strength of Intact Ship Structures

2021 ◽  
Vol 9 (10) ◽  
pp. 1079
Author(s):  
Mesut Tekgoz ◽  
Yordan Garbatov
Keyword(s):  
Ultimate Strength ◽  
Structural Design ◽  
Structural Failure ◽  
Box Girders ◽  
Ship Structures ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Structural Capacity ◽  
Longitudinal Strength ◽  
Future Work

Ship structures are subjected to complex sea loading conditions, leading to a sophisticated structural design to withstand and avoid structural failure. Structural capacity assessment, particularly of the longitudinal strength, is crucial to ensure the safety of ships, crews, the marine environment, and the cargoes carried. This work aims to overview the ultimate strength assessment of intact ship structures in recent decades. Particular attention is paid to the ultimate strength of plates, stiffened panels, box girders, and entire ship hull structures. A discussion about numerical and experimental analyses is also provided. Finally, some conclusions and suggestions about potential future work are noted.

Buckling and Ultimate Strength Assessment of FPSO Structures

2005 ◽  
Author(s):  
Haihong Sun ◽  
Xiaozhi Wang
Keyword(s):  
Ultimate Strength ◽  
Oil And Gas ◽  
Element Analysis ◽  
Strength Criteria ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Oil And Gas Fields ◽  
Extensive Test ◽  
Offshore Oil And Gas ◽  
Classification Society

Floating production, storage and offloading systems (FPSOs) have been widely used for the development of offshore oil and gas fields because of their attractive features. They are mostly ship- shaped, either converted from existing tankers or purposely built, and the hull structural scantling design for tankers may be applicable to FPSOs. However, FPSOs have their unique characteristics. FPSOs are sited at specific locations with a dynamic loading that is quite different from those arising from unrestricted service conditions. The structures are to be assessed to satisfy the requirements of all in-service and pre-service loading conditions. The fundamental aspects in the structural assessment of FPSOs are the buckling and ultimate strength behaviors of the plate panels, stiffened panels and hull girders. The focus of this paper is to address the buckling and ultimate strength criteria for FPSO structures. Various aspects of the criteria have been widely investigated, and the results of the design formulae proposed in this paper have been compared to a very extensive test database and numerical results from nonlinear finite element analysis and other available methods. The procedures presented in this paper are based on the outcomes of a series of classification society projects in the development of buckling and ultimate strength criteria and referred to the corresponding classification society publications.

Estimate of the Ultimate Load on Structural Members Subjected to Lateral Loads

2001 ◽  
Vol 38 (03) ◽  
pp. 169-176
Author(s):  
L. Belenkiy ◽  
Y. Raskin
Keyword(s):  
Finite Element ◽  
Limit Analysis ◽  
Ultimate Load ◽  
Limit Load ◽  
Plastic Behavior ◽  
Lateral Loads ◽  
Ship Structures ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Plate Elements

This paper examines plastic behavior of typical ship structures, specifically beams, grillages, and plates subjected to predominantly lateral loads. The ultimate loads, determined on the basis of the theorems of limit analysis [1,2], are evaluated using nonlinear finite-element plastic analysis. The relationships between analytical and finite-element models for prediction of ultimate loads of beams, stiffened panels, and grillages are illustrated. It has been shown that the ultimate loads, obtained from the theorems of limit analysis, can be successfully used for strength assessment of stiffened ship structures subjected to lateral loads. The effect of shear force on ultimate load is analyzed using the finite-element method. This paper confirms that in the case of beams and grillages under lateral loading, the ultimate load may characterize the threshold of the load at which a stiffened ship's structure fails by the development of excessive deflections. For plate elements, on the other hand, the plastic deflections represent the permissible limit of external load better than the ultimate limit load.

Residual ultimate strength assessment of stiffened panels with locked cracks

2014 ◽  
Vol 85 ◽  
pp. 398-410 ◽  
Author(s):  
Ming Cai Xu ◽  
Y. Garbatov ◽  
C. Guedes Soares
Keyword(s):  
Ultimate Strength ◽  
Strength Assessment ◽  
Stiffened Panels

Comparison Study of Various Buckling and Ultimate Strength Assessment Methodologies for Stiffened Panels in Offshore Structures

2010 ◽  
Author(s):  
Xiaozhi Wang ◽  
Haihong Sun ◽  
Xiaohong Wang ◽  
Zhinong Wang ◽  
Anil Thayamballi
Keyword(s):  
Ultimate Strength ◽  
Offshore Structures ◽  
Design Analysis ◽  
Plastic Behavior ◽  
Comparison Study ◽  
Element Analysis ◽  
Strength Assessment ◽  
Stiffened Panels ◽  
Linear Elastic ◽  
Local Strength

Strength of offshore structures including FPSOs consists broadly of three aspects which are global intact and damaged strength, and local strength. Any of these strength aspects can be assessed by either prescriptive rule or finite element analysis (FEA). While many considerations relate to behavior in the linear elastic regime, the buckling and ultimate strength of both structural components (plate and stiffened panels) and structural systems can involve material and geometric nonlinearity behavior beyond the elastic region. With the development of computers and robust methods for nonlinear FEA, there has been a tremendous increase in the number of studies of structures under plastic or elasto-plastic behavior. However, even with today’s computers and software, nonlinear FEA of offshore structures remains complex and is not routinely applied in design analysis. Considerable effort therefore continues to be devoted to the development of simplified methods for rapid structural assessment and design analysis, instead of lengthy and complex nonlinear FEA. In this paper, various bucking and ultimate strength methodologies for plate and stiffener panels are first introduced. Each method is then compared with collected test data for buckling and ultimate strength of plate panels and stiffeners. Finally, conclusions are summarized based on the comparison study.

Assessment of Residual Ultimate Hull Girder Strength of Damaged Ships

2014 ◽  
Author(s):  
Xiaoli Jiang ◽  
Haiyang Yu ◽  
Miroslaw Lech Kaminski
Keyword(s):  
Ultimate Strength ◽  
Oil Spills ◽  
Damage Model ◽  
Ship Hull ◽  
Element Analysis ◽  
Detailed Measurement ◽  
Hull Girder ◽  
Damage Models ◽  
Actual Damage ◽  
Damaged Ship

The risk of ship collision and grounding has increased significantly in recent years as a result of the growing size and number of ships at sea. The potentially costly consequences of collision and grounding in the form of fatalities, property, and cargo, as well as environmental pollution in the form of oil spills, etc., are the main motivations for research on collision and grounding. From a structural evaluation standpoint, there is a great deal of uncertainty related to the residual strength of damaged ships considering various influential parameters, such as damage size, geometry and location, internal structural arrangement, material property, loading case, and sea weather. Therefore, it is important to clarify the residual hull girder strength of damaged ships by collision or grounding in order to ensure their safety. The present study undertook a deliberate finite element analysis to investigate the residual ultimate strength of damaged ship hull, where two damage models were assumed and compared. One model simulated actual damage resulting from an accident in the form of hole with adjacent plastic deformation, while the other applied simplified damage, considering unavailable measurement of the damage by removing the damaged part from the original ship hull. The comparison showed that the assessment of residual ultimate strength of a damaged ship based on the simplified damage model could produce a sufficiently accurate result and stay slightly safer, provided that a reasonable criterion of simplification was defined first. The studies showed that it is possible to accurately estimate the residual ultimate strength of a damaged ship without detailed measurement of the damage, and consequently facilitate decision-making regarding the ship salvage under emergency.

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