A NEW METHOD FOR ASSESSING THE SAFETY OF SHIPS DAMAGED BY GROUNDING

2021 ◽  
Vol 154 (A1) ◽  
Author(s):  
J.K. Paik ◽  
D.K. Kim ◽  
D.H Park ◽  
H.B. Kim ◽  
M.S. Kim
Keyword(s):  
Residual Strength ◽  
Structural Damage ◽  
Damage Index ◽  
Sampling Technique ◽  
Damage Scenario ◽  
Strength Performance ◽  
Damage Scenarios ◽  
Longitudinal Strength ◽  
Oil Tankers ◽  
Double Hull

The primary aim of the present study is to propose an innovative method for assessing the safety of ships which have suffered accidental or in-service damages. Only a small number of probable scenarios for accidental or in-service damage representing all possible damage scenarios are selected using a sampling technique in which the random variables affecting the damage are probabilistically characterized. A damage index for the corresponding damage scenario is defined as a function of damage characteristics such as location and extent of the damage. The residual strength performance of a ship with the corresponding damage scenario can then be calculated by analytical or numerical methods. Once this process has been carried out for each of the damage scenarios selected, a diagram relating the residual strength performance to the damage index (abbreviated as the R-D diagram) can be established. This diagram will be very useful for a first-cut assessment of a ship’s safety immediately after it has suffered structural damage. The diagram can also be used to determine acceptance criteria for a ship’s safety against accidental or in-service damage. An applied example is shown to demonstrate the applicability of the proposed method in terms of developing a diagram between the ultimate longitudinal strength versus grounding damage index for four types of double-hull oil tankers – VLCC, Suezmax, Aframax, and Panamax.

A New Method for Assessing the Safety of Ships Damaged by Grounding

2012 ◽  
Vol 154 (A1) ◽  
Keyword(s):  
Residual Strength ◽  
Structural Damage ◽  
Damage Index ◽  
Sampling Technique ◽  
Damage Scenario ◽  
Strength Performance ◽  
Damage Scenarios ◽  
Longitudinal Strength ◽  
Oil Tankers ◽  
Double Hull

The primary aim of the present study is to propose an innovative method for assessing the safety of ships which have suffered accidental or in-service damages. Only a small number of probable scenarios for accidental or in-service damage representing all possible damage scenarios are selected using a sampling technique in which the random variables affecting the damage are probabilistically characterized. A damage index for the corresponding damage scenario is defined as a function of damage characteristics such as location and extent of the damage. The residual strength performance of a ship with the corresponding damage scenario can then be calculated by analytical or numerical methods. Once this process has been carried out for each of the damage scenarios selected, a diagram relating the residual strength performance to the damage index (abbreviated as the R-D diagram) can be established. This diagram will be very useful for a first-cut assessment of a ship’s safety immediately after it has suffered structural damage. The diagram can also be used to determine acceptance criteria for a ship’s safety against accidental or in-service damage. An applied example is shown to demonstrate the applicability of the proposed method in terms of developing a diagram between the ultimate longitudinal strength versus grounding damage index for four types of double-hull oil tankers – VLCC, Suezmax, Aframax, and Panamax.

Development of a Relationship Between Residual Ultimate Longitudinal Strength Versus Grounding Damage Index Diagram for Container Ships

2012 ◽  
Author(s):  
Do Kyun Kim ◽  
Han Byul Kim ◽  
Xiaoming Zhang ◽  
Preben Terndrup Pedersen ◽  
Min Soo Kim ◽  
...  
Keyword(s):  
Structural Damage ◽  
Damage Index ◽  
International Maritime Organization ◽  
Longitudinal Strength ◽  
Fire And Explosion ◽  
Damage Criteria

Various accidents such as grounding, collision, fire, and explosion commonly occur on operating ships. The structural damage caused by such accidents is often accompanied by casualties and serious pollution. Therefore, an accidental risk-based approach that is in line with the goal-based standard of the International Maritime Organization is being developed in the literature. In the present paper, the residual ultimate longitudinal strength versus grounding damage diagram (R-D diagram) for container ships is established as per the method of Paik et al. [1]. The proposed R-D diagram should be useful for defining acceptance damage criteria and making rapid salvage plans or rescue schemes for container ships that have sustained a grounding accident.

QUANTITATIVE RISK ASSESSMENT FOR COLLISIONS INVOLVING DOUBLE HULL OIL TANKERS

2021 ◽  
Vol 156 (A2) ◽  
Author(s):  
S A M Youssef ◽  
S T Ince ◽  
Y S Kim ◽  
J K Paik ◽  
F Chang ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Structural Damage ◽  
Human Life ◽  
Quantitative Risk Assessment ◽  
Environmental Damage ◽  
Total Risk ◽  
Formal Safety Assessment ◽  
Environmental Damages ◽  
Oil Tankers ◽  
Double Hull

In recent decades, the safety of ships at sea has become a major concern of the global maritime industries. Ships are rarely subject to severe accidents during their life cycle. Collision is one of the most hazardous accidents, with potentially serious consequences such as the loss of human life, structural damage and environmental damage, especially if large tankers, LNG and/or nuclear-powered vessels are involved. This study presents a Quantitative Risk Assessment (QRA) for double hull oil tankers that have collided with different types of ships. The methodology used to perform the QRA is based on the International Maritime Organization’s (IMO) definition of a Formal Safety Assessment (FSA). Using probabilistic approaches, ship-ship collision scenarios are randomly selected to create a representative sample of all possible scenarios. The collision frequency is then calculated for each scenario. As this is a virtual experiment, the LS-DYNA nonlinear finite element method (NLFEM) is used to predict the structural consequences of each scenario selected. In addition, the environmental consequences are estimated by calculating the size of each scenario’s oil spill. To assess the economic consequences, the property and environmental damages are calculated in terms of monetary units. The total risk is then calculated as the sum of the resultant structural and environmental damages. Exceedance curves are established that can be used to define the collision design loads in association with various design criteria.

Rapid Assessment of Hull Girder Collapse for Corroded Double Hull Oil Tanker After Collision

2016 ◽  
Author(s):  
Sung Hwan Noh ◽  
Jung Kwan Seo ◽  
Jeom Kee Paik ◽  
Samy A. M. Youssef
Keyword(s):  
Finite Element ◽  
Structural Damage ◽  
Rapid Assessment ◽  
Probabilistic Approach ◽  
Hull Girder ◽  
The Alps ◽  
Oil Tankers ◽  
Double Hull ◽  
Oil Tanker ◽  
Probability Density Function Pdf

Corroded tankers might be subjected to a very serious structural damage if involved in collision accidents. For understanding or preventing the collision accidents, various studies are being proposed by researchers to improve the analysis method. In this paper, four types of double hull oil tankers (Panamax, Aframax, Suezmax and VLCC) are used. Probabilistic approach is used to create ship-ship collision scenarios for each target structure and the ultimate longitudinal hull girder strength of the hypothetical oil tanker’s hull cross-section. The ALPS/HULL is used to simulate and is intelligent supersize finite element method (ISFEM) software. A relevant probability density function (PDF) is introduced using the results from finite element simulations of the ship-ship collisions, which is commonly used to predict residual strength.

Development of Rapid Prediction Method for Residual Strength of Oil Tankers Subjected to Ship-Ship Collision

2018 ◽  
Author(s):  
Seung Jun Baek ◽  
Jung Min Sohn ◽  
Jeom Kee Paik ◽  
Sang Jin Kim
Keyword(s):  
Empirical Formula ◽  
Structural Damage ◽  
Marine Pollution ◽  
Prediction Method ◽  
Financial Loss ◽  
Hull Girder ◽  
Special Skill ◽  
Oil Tankers ◽  
Marine Accidents ◽  
Double Hull

Collision and grounding accidents account for more than half of all accident cases in most cases. Such marine accidents cause severe structural damage to the ship and lead to marine pollution as well as life and financial loss. For preventing the loss of property and pollution, and preparing a countermeasure, it is needed to predict a residual hull girder strength after accident regardless of someone’s special skill. The aims of this study are to i) investigate the residual hull girder strength by quantitative approach with collision location (height and penetration), ii) develop an empirical formula for calculating a residual hull girder strength which whoever can calculate in association with collision locations. In this study, three kinds of ships such as very large crude oil carrier, Suezmax, and Aframax class double hull oil tankers are selected as target struck vessels. And, the Intelligent Supersize Finite Element Method (ISFEM) is applied to assess the residual hull girder strength of damaged structures after collisions. Based on the ISFEM results, an empirical formula for calculation of residual hull girder strength is developed as a function of the collision depth and penetration. The developed formula in this study can be applied by anyone, and rapidly calculate its strength for preventing sequential events (collapse, fuel spill, etc.) after collision.

Determination of Critical Factors for the Strength Assessment of Damaged Steel Ship Structures

2011 ◽  
Author(s):  
J. M. Underwood ◽  
A. J. Sobey ◽  
J. I. R. Blake ◽  
R. A. Shenoi ◽  
B. R. Cuckson
Keyword(s):  
Residual Strength ◽  
Material Properties ◽  
Progressive Collapse ◽  
Limit State ◽  
Damage Scenario ◽  
Element Analysis ◽  
Strength Assessment ◽  
Damage Scenarios ◽  
Steel Panels ◽  
High Level

A significant number of damage events continue to occur to ocean going vessels, many of which remain afloat in need of assistance to evaluate remedial actions to minimise the risk of further damage and conditions for onward transit for a repair facility. Therefore, it is vital that the post damage situation is rapidly understood to reduce damage propagation occurring, reducing the cost of repair and allowing more vessels to be recovered safely, ensuring the safety of personnel onboard. After an incident, it is often difficult to determine and model the precise damage scenario due to the inability to survey the area. Each scenario will have variability in geometrical and material properties, which will affect the residual strength of the structure. Variations in these aspects are not accounted for in methods currently utilised in damage response scenarios. Therefore, to be able to more accurately analyse the damage and provide better guidance to the crew in real time, it is important that this variability can be analysed, allowing an understanding of worst and best case scenarios, the probabilities of these occurring and their affect on the structural strength. Finite element analysis has been used to model damage scenarios due to the high level of accuracy that can be achieved. This paper demonstrates the implications of damage aperture on the limit state of stiffened steel panels, investigating the residual strength of the damaged structures and their sensitivity to variations in damage event, geometric and material properties. The results are then compared with the Smith and Dow progressive collapse method, [1,2], with conclusions being drawn about the use of this method in damage situations. Further to this, the effects of variability in the ship are investigated for damage scenarios, showing that these influence the ultimate strength of the structure to a larger extent in the failure of damaged plates than intact scenarios; however, lack of knowledge relating to the area of the damage could overshadow other potential variability within these scenarios.

scholarly journals Experimental Study on Damage Detection in ECC-Concrete Composite Beams Using Piezoelectric Transducers

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2799
Author(s):  
Fengjiang Qin ◽  
Zhigang Zhang ◽  
Bo Xie ◽  
Rui Sun
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Structural Integrity ◽  
Damage Index ◽  
Composite Beams ◽  
Damage State ◽  
Damage Scenarios ◽  
Electromechanical Impedance ◽  
Externally Bonded ◽  
Unique Strain

The use of engineered cementitious composite (ECC) has attracted extensive attention in recent years because of the highly enhanced ductility owing to its unique strain-hardening behavior. In this paper, an electromechanical impedance-based technique is used to monitor the structural damage of RC beams strengthened with an ECC layer at the tensile zone. To achieve this purpose, three specimens are tested under bending loads to evaluate the proposed damage detection methodology. Five externally bonded PZT transducers are uniformly distributed at the surface of the ECC layer of the beams to measure the output conductance signatures in a healthy state and in different damage scenarios induced by different load levels. Test results showed that discrepancies exist between the signals measured in the intact state and each damage state, which can be used to evaluate the structural integrity changes. To assess the damage of ECC-concrete composite beams quantitatively, the statistical scalar index-root mean square deviation (RMSD) is used as the index, which can be calculated from the variations of conductance measurements of PZT sensors. The damage index values of the uniformly distributed PZT sensors provided cogent evidence of damage and revealed the evolution of structural damage. The crack patterns of beams at different damage levels are compared with the damage index values, and it shows the damage location can be derived from the measured conductance signatures of an array of PZT transducers.

Structural Damage Detection Using Signal Pattern-Recognition

2008 ◽  
Vol 400-402 ◽  
pp. 465-470 ◽  
Author(s):  
Long Qiao ◽  
Asad Esmaeily ◽  
Hani G. Melhem
Keyword(s):  
Pattern Recognition ◽  
Damage Detection ◽  
Structural Damage ◽  
Experimental Studies ◽  
Least Square ◽  
Structural Damage Detection ◽  
Damage Scenario ◽  
Damage Pattern ◽  
Damage Scenarios ◽  
Unknown Damage

Deterioration significantly affects the structure performance and safety. A signal-based pattern-recognition procedure is applied for structural damage detection with a limited number of input/output signals. The method is based on extracting and selecting the sensitive features of the structure response to form a unique pattern for any particular damage scenario, and recognizing the unknown damage pattern against the known database to identify the damage location and level (severity). In this study, two types of transformation algorithms are implemented separately for feature extraction: (1) Continuous Wavelet Transform (CWT); and (2) Wavelet Packet Transform (WPT). Three pattern-matching algorithms are also implemented separately for pattern recognition: (1) correlation, (2) least square distance, and (3) Cosh spectral distance. To demonstrate the validity and accuracy of the procedure, experimental studies are conducted on a simple three-story steel structure. The results show that the features of the signal for different damage scenarios can be uniquely identified by these transformations, and correlation algorithms can best perform pattern recognition to identify the unknown damage pattern. The proposed method can also be used to possibly detect the type of damage. It is suitable for structural health monitoring, especially for online monitoring applications.

scholarly journals DOUBLE HULL OIL TANKERS—HOW EFFECTIVE ARE THEY?

1993 ◽  
Vol 1993 (1) ◽  
pp. 745-751
Author(s):  
Virgil F. Keith
Keyword(s):  
Control Systems ◽  
Oil Spill ◽  
Structural Damage ◽  
Oil Spills ◽  
State Of The Art ◽  
North Slope ◽  
First Line ◽  
Safety Measures ◽  
Oil Tankers ◽  
Double Hull

ABSTRACT The groundings of the Exxon Valdez on Bligh Reef in Prince William Sound, spilling more than 10 million gallons of Alaska North Slope crude, and the American Trader off Huntington Beach, spilling almost 400,000 gallons of Alaska North Slope crude, suggest that the construction of oil tankers be re-examined with respect to a design which could reduce both the number and magnitude of oil spills. This paper discusses state-of-the-art tanker technology with respect to spill prevention, effectiveness, and cost. The design features include double hulls, centralized bunker tankers, vacuum-retaining valves, cargo control systems, auxiliary thrusters, electronic charting, and the retransmission of the ship's position. Double hulls provide the highest probability of surviving damage, either from a collision or grounding, with no loss of cargo. Use of double hulls can reduce oil spill incidence by 90 percent in grounding situations and by 75 percent in collisions. The oil spill from the American Trader could have been completely avoided by double hull construction. The arrangement provides spaces below the cargo tanks and on the vessel's sides solely for the carriage of ballast water when the tanker is in ballast condition. These tanks are empty when the tanker is loaded and then also act as the first line of defense in the event of structural damage to the cargo tanks. Tanker design is integrated with port safety measures, including vessel monitoring systems, in this total spill prevention analysis. All aspects of the tanker transportation system are considered.

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