Investigation of the 2nd Generation of Intact Stability Criteria for Ships Vulnerable to Parametric Rolling in Following Seas

2013 ◽  
Author(s):  
Stefan Krüger ◽  
Hannes Hatecke ◽  
Heike Billerbeck ◽  
Anna Bruns ◽  
Florian Kluwe
Keyword(s):  
Dynamic Stability ◽  
Direct Calculation ◽  
Stability Criteria ◽  
Parametric Rolling ◽  
Following Seas ◽  
2Nd Generation ◽  
Direct Assessment ◽  
Intact Stability ◽  
New Criteria ◽  
Level 2

The existing IMO intact stability criteria (IS-Code 2008) do not generally provide sufficient safety against dynamic stability failures such as parametric rolling for modern ships. Therefore, new stability criteria have been developed by IMO / SLF. These so-called Second Generation Stability Criteria shall ensure sufficient dynamic stability. The criteria are structured in a three level approach, where the first level consists of quite simple formulae. If a ship does not pass the first level, it is assumed that the ship is vulnerable to the phenomenon addressed, and the second level of criteria shall then be applied. This level consists of computations which are a little more complex, but they still treat the problems addressed in a strongly simplified manner. If now the ship does not pass the second level, a third level shall be applied to ensure that the ship can be designed and operated safely. This third level consists of direct calculation methods which shall be applied, however no criteria or procedures have yet been developed for this third level. We have applied the level 1 and level 2 criteria to a reference ship where a direct stability assessment has been performed during the design. The results showed extremely large scatter in the required GM-values of the criteria, and none of the criteria showed GM values roughly comparable to the direct assessment. The paper shows why the application of the criteria is challenging for the design of RoRo-ships and why a third level (direct assessment) is urgently required before the first two levels are put into force. Some conclusions are also drawn for the possible treatment of the new criteria in a stability booklet.

Empirical and experimental roll damping estimates for an oil tanker in the context of the 2nd generation intact stability criteria

2019 ◽  
Vol 189 ◽  
pp. 106291 ◽  
Author(s):  
Mauro Costa de Oliveira ◽  
Bruno de Barros Mendes Kassar ◽  
Luiz Cristovão Gomes Coelho ◽  
Flávia Vieira Monteiro ◽  
Rafael Torres de Santis ◽  
...  
Keyword(s):  
Stability Criteria ◽  
Roll Damping ◽  
2Nd Generation ◽  
Intact Stability ◽  
Oil Tanker

scholarly journals The Application of 2nd Generation Intact Stability Criteria to Ship Operating in Indonesia Waterway: Pureloss Stability

2021 ◽  
Vol 1052 (1) ◽  
pp. 012050
Author(s):  
S Anggara ◽  
R D Maskar ◽  
M R F Hariadi ◽  
L M Ichsan ◽  
M Zaky ◽  
...  
Keyword(s):  
Stability Criteria ◽  
2Nd Generation ◽  
Intact Stability

Recent Coast Guard Research into Vessel Stability

1974 ◽  
Vol 11 (04) ◽  
pp. 329-339
Author(s):  
D. M. Bovet ◽  
R. E. Johnson ◽  
E. L. Jones
Keyword(s):  
Coast Guard ◽  
Stability Criteria ◽  
Fishing Vessel ◽  
Following Seas ◽  
Intact Stability ◽  
Passenger Ships ◽  
Computer Simulation Program ◽  
General Cargo ◽  
The University ◽  
Vessel Stability

The paper outlines the development of intact stability criteria for U. S. merchant vessels. Present stability criteria for passenger ships, general cargo ships, tugboats, etc. as well as stability criteria recommended by the Intergovernmental Maritime Consultative Organization are discussed. The paper describes the research into intact stability phenomena that is being sponsored by the U. S. Coast Guard. Results and the scope of the programs at the University of California at Berkeley to investigate ship stability in a seaway and Hydronautics, Inc. to investigate tugboat and fishing vessel stability and the applicability of present criteria are presented. The last section of the paper describes a computer simulation program developed by one of the authors to predict capsizing in following seas.

Validation of Volterra Series Approach for Modelling Parametric Rolling of Ships

2015 ◽  
Author(s):  
Abhilash S. Somayajula ◽  
Jeffrey M. Falzarano
Keyword(s):  
Validation Studies ◽  
Volterra Series ◽  
Equations Of Motion ◽  
Series Representation ◽  
Analytical Techniques ◽  
Simplified Model ◽  
Stability Criteria ◽  
Parametric Roll ◽  
Parametric Rolling ◽  
Following Seas

Parametric motion is the phenomenon where a structure is excited into large amplitude motion even when there is no direct excitation. A well-known example of this type of motion is the parametric roll of ships in head or following seas. Parametric roll of container ships in head seas is relatively a new problem which has gained much importance after the catastrophic incidence of APL China in 1998. Although a lot of analytical techniques are available on the assessment of parametric roll in regular excitation, not many investigations have explored its occurrence in irregular seas. A consensus on the stability criteria to assess the danger due to this phenomenon in actual ocean has not yet been reached making it an active area of investigation. A precursor to the development of stability criteria is a simple model to capture the phenomenon of parametric rolling. However, it is important that the model is not over simplified and ignores important dynamics of the process. Therefore it is necessary to perform validation studies between the simplified model and the complete nonlinear model capturing all the physics of the phenomenon. This paper provides the validation studies of a 1-DOF (degree of freedom) simplified model for roll motion against a standard 6-DOF time domain simulation approach. The 1-DOF model is based on the Volterra series representation of the hydrostatic stiffness in waves while accounting for the heave and pitch motions of the model. It also includes a nonlinear damping model capturing the radiation and the viscous damping. The 6-DOF model solves for the nonlinear equations of motion based on Euler angles and also includes the nonlinear Froude Krylov excitations and nonlinear hydrostatic forces on the vessel. Details of the modeling in the two approaches are described and comparisons are performed to assess the validity of 1-DOF simplified model.

scholarly journals Excessive Acceleration Criterion: Application to Naval Ships

2019 ◽  
Vol 7 (12) ◽  
pp. 431 ◽  
Author(s):  
Guido Boccadamo ◽  
Gennaro Rosano
Keyword(s):  
Failure Modes ◽  
Vertical Direction ◽  
Naval Research ◽  
Stability Criteria ◽  
Office Of Naval Research ◽  
Intact Stability ◽  
The Us ◽  
Ship Roll ◽  
Hull Forms ◽  
Level 2

In this paper, the application of the excessive acceleration (EA) criterion, one of five intact stability failure modes, within the second generation intact stability criteria (SGISC) framework, is shown for a set of naval vessels. First and second level vulnerability assessment of the criterion is applied to parent hulls D1 and D5 of D-Systematic Series, the US Office of Naval Research (ONR) Topside Series model, and the European multi-purpose frigate FREMM. All of which are semi-displacement, transom stern, and round bilge hull forms. Relatively low ship roll periods and great variations of hull geometry in vertical direction make this kind of ship potentially vulnerable to the EA phenomenon. Five displacements are considered for each vessel, and the minimum value of the KG height, which satisfies the Level 2 assessment, is computed for each of them. The curve of the minimum allowable KG is compared with the curve of the maximum KG complying with intact stability criteria specified in RINA (Registro Italiano Navale), classification rules for naval ships.

Second Generation Intact Stability Criteria Fallout on Naval Ships Limiting KG Curves

2020 ◽  
Author(s):  
Gennaro Rosano ◽  
Ermina Begović ◽  
Guido Boccadamo ◽  
Barbara Rinauro
Keyword(s):  
Dynamic Stability ◽  
Second Generation ◽  
Loss Of Stability ◽  
Stability Criteria ◽  
Parametric Roll ◽  
Intact Stability ◽  
Surf Riding ◽  
Hull Forms ◽  
Onr Tumblehome ◽  
Dead Ship Condition

The International Maritime Organization (IMO) finalized the Second Generation Intact Stability Criteria (SGISC), in February 2020. They are intended to be included in Part A of the 2008 International Code on Intact Stability in the following years. The SGISC consider five modes of dynamic stability failure in waves: parametric roll, pure loss of stability, surf-riding/broaching to, dead ship condition and excessive acceleration. In this paper, two semi-displacement, round bilge and transom stern hull forms, the parent hull of the Systematic Series D and the ONR Tumblehome, i.e. typical naval hull forms, are examined. Although naval ships are not directly impacted by SGISC, they are sensitive to dynamic stability failure phenomena due to their geometry and range of service speeds. The procedures to assess the ship vulnerability to the dead ship condition and excessive acceleration criteria, referring to the latest drafts of the criteria (SDC 7/5, 2019), were implemented in Matlab®,. The limiting KG curves associated with this set of criteria were obtained for each vessel. The minimum allowable KG curve associated with the excessive acceleration criterion was compared with the maximum allowable KG curve associated with dead ship condition, to investigate the existence of a safe operational area.

Evaluation of the Dynamic-Response-Based Intact Stability Criterion for Floating Wind Turbines

2015 ◽  
Author(s):  
Marco Masciola ◽  
Xiaohong Chen ◽  
Qing Yu
Keyword(s):  
Wind Speed ◽  
Dynamic Response ◽  
Wind Turbines ◽  
Stability Criterion ◽  
Area Ratio ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Stability Criteria ◽  
Intact Stability ◽  
Overturning Moment

As an alternative to the conventional intact stability criterion for floating offshore structures, known as the area-ratio-based criterion, the dynamic-response-based intact stability criteria was initially developed in the 1980s for column-stabilized drilling units and later extended to the design of floating production installations (FPIs). Both the area-ratio-based and dynamic-response-based intact stability criteria have recently been adopted for floating offshore wind turbines (FOWTs). In the traditional area-ratio-based criterion, the stability calculation is quasi-static in nature, with the contribution from external forces other than steady wind loads and FOWT dynamic responses captured through a safety factor. Furthermore, the peak wind overturning moment of FOWTs may not coincide with the extreme storm wind speed normally prescribed in the area-ratio-based criterion, but rather at the much smaller rated wind speed in the power production mode. With these two factors considered, the dynamic-response-based intact stability criterion is desirable for FOWTs to account for their unique dynamic responses and the impact of various operating conditions. This paper demonstrates the implementation of a FOWT intact stability assessment using the dynamic-response-based criterion. Performance-based criteria require observed behavior or quantifiable metrics as input for the method to be applied. This is demonstrated by defining the governing load cases for two conceptual FOWT semisubmersible designs at two sites. This work introduces benchmarks comparing the area-ratio-based and dynamic-response-based criteria, gaps with current methodologies, and frontier areas related to the wind overturning moment definition.

Parametric Vibration of a Flexible Structure Excited by Periodic Passage of Moving Oscillators

2020 ◽  
Vol 87 (7) ◽  
Author(s):  
Hao Gao ◽  
Bingen Yang
Keyword(s):  
Dynamic Stability ◽  
Parametric Resonance ◽  
Flexible Structures ◽  
Coupled System ◽  
Analytical Form ◽  
Stability Criteria ◽  
Analysis Method ◽  
State Equations ◽  
Supporting Structure ◽  
Moving Oscillator

Abstract Flexible structures carrying moving subsystems are found in various engineering applications. Periodic passage of subsystems over a supporting structure can induce parametric resonance, causing vibration with ever-increasing amplitude in the structure. Instead of its engineering implications, parametric excitation of a structure with sequentially passing oscillators has not been well addressed. The dynamic stability in such a moving-oscillator problem, due to viscoelastic coupling between the supporting structure and moving oscillators, is different from that in a moving-mass problem. In this paper, parametric resonance of coupled structure-moving oscillator systems is thoroughly examined, and a new stability analysis method is proposed. In the development, a set of sequential state equations is first derived, leading to a model for structures carrying a sequence of moving oscillators. Through the introduction of a mapping matrix, a set of stability criteria on parametric resonance is then established. Being of analytical form, these criteria can accurately and efficiently predict the dynamic stability of a coupled structure-moving oscillator system. In addition, by the spectral radius of the mapping matrix, the global stability of a coupled system can be conveniently investigated in a parameter space. The system model and stability criteria are illustrated and validated in numerical examples.

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