Research on Some Issues related to Fatigue Assessment based on Latest IACS Harmonized CSR Amendments

2015 ◽  
Author(s):  
Wu Jiameng ◽  
Cai Shijian ◽  
Wang Weifei
Keyword(s):  
Structural Design ◽  
Fe Analysis ◽  
Fatigue Assessment ◽  
Structural Rules ◽  
Bulk Carriers ◽  
Key Issues ◽  
Common Structural Rules ◽  
Oil Tankers ◽  
The Impact

The IACS Harmonized Common Structural Rules (CSR-H) for Bulk Carriers and Oil Tankers has been issued on 1st Jan 2014, and will enter into force on 1st July 2015 to supersede the current CSR version (CSR-BC or CSR-OT). The latest amendments to 01 Jan 2014 version of CSR-H give lots of significant modifications on fatigue assessment. The purpose of this study is to introduce the main changes for fatigue requirement in such amendments, and evaluate their rationality based on some detailed FE analysis for some key issues. Meanwhile, the impact on the structural design, especially on the scantlings, will be discussed as well as some proposal. Some typical bulk carriers and oil tankers are investigated.

Ramification Study on IACS Harmonized Common Structural Rules: Impact on Structural Design and Scantlings

2014 ◽  
Author(s):  
Wu Jiameng ◽  
Wang Gang ◽  
Cai Shijian
Keyword(s):  
Structural Design ◽  
Classification Rule ◽  
Design Parameters ◽  
Functional Requirements ◽  
Safety Level ◽  
Structural Rules ◽  
Bulk Carriers ◽  
Common Structural Rules ◽  
Oil Tankers ◽  
New Criteria

The Harmonized Common Structural Rules (CSR-H) for Bulk Carriers and Oil Tankers has been issued on 1st Jan 2014, and will enter into force on 1st July 2015 to supersede the current two separate CSR versions, namely CSR-OT for Oil tankers and CSR-BC for bulk carriers. CSR-H aims at a consistent methodology harmonizing CSR-OT and CSR-BC, and establishes new criteria and requirements with the further aim of compliance with the IMO Goal Based Standard (GBS) where GBS functional requirements fall within Classification Rule scope. To maintain equivalent or higher safety level than current CSR, the rule developments within CSR-H are as a guideline aimed at scantling requirements that will be the same or higher for a given CSR vessel given the same ship design parameters and structural arrangement both globally and locally. The purpose of this study is to introduce the main changes from CSR to CSR-H, the new criteria set up for GBS compliance, and evaluate their impact on the structural design, especially on the scantlings. A carefully selected set of ten bulk carriers and eight oil tankers are investigated with the focus not only on the midship area but also on the foremost and aftmost cargo block areas as well. The typical critical areas affected by CSR-H due to fatigue or buckling criteria are identified, discussed and analyzed in detail. The impacts on scantlings and improvement suggestions for structural design based on CSR-H are further summarized and conclusions made.

Numerical Prediction of Sloshing Loads in Ship Tanks

2008 ◽  
Author(s):  
Sanjay P. Singh ◽  
Anant Lal ◽  
Sharad S. Dhavalikar
Keyword(s):  
Structural Response ◽  
Time History ◽  
Ship Motions ◽  
Flow Solver ◽  
Structural Rules ◽  
Ansys Cfx ◽  
Pressure Time ◽  
Fill Level ◽  
Common Structural Rules ◽  
Oil Tankers

The present work is about the estimation of sloshing loads in partially filled tanks of a ship for design purpose. Two oil tankers of different dimensions were taken for this study. Ship motions for several wave-heading angles were computed using potential flow solver. Relevant period for sloshing was determined based on the seakeeping analysis. Critical fill levels of the tanks (with respect to sloshing) were identified from all possible set of motions. The numerical simulation of tank fluid motions for critical fill level was performed, using general fluid flow solver, ANSYS CFX. Prior to applying the method to ship tanks a validation study was carried out. The method was validated against the experimental results obtained by Hinatsu et al. (2001). Pressures at various locations of the tank were computed and were compared with the Common Structural Rules for Oil Tankers (CSR). Pressure time history obtained from computational fluid dynamics (CFD) simulations was applied on the tank bulkhead to get the structural response, using ANSYS Mechanical.

The Development of Common Structural Rules for Tankers

2005 ◽  
Author(s):  
Gary E. Horn
Keyword(s):  
General Public ◽  
Development Process ◽  
Project Team ◽  
Structural Requirements ◽  
Technical Aspects ◽  
Structural Rules ◽  
Standardization Process ◽  
The Common ◽  
Common Structural Rules ◽  
The Impact

In late 2001 classification societies Lloyd’s Register, the American Bureau of Shipping and Det Norske Veritas (LR, ABS and DNV) announced plans to standardize a wide number of mutually agreed upon initiatives covering survey and engineering. This standardization process was precipitated as a response to calls for more robust requirements as well as a Class response to calls for improvement made by governments, industry and the general public. One of the initiatives was the establishment of a joint tanker project team (JTP) to develop Common Structural Rules for Tankers so that competition on structural requirements (safety) would be eliminated. Once the common rules are finalized and in effect, they will replace the current tanker rules of LR, ABS and DNV. This paper outlines the rule development process, key technical aspects of the common rules, the impact to the design scantlings, and future maintenance of these rules.

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.

scholarly journals Normative and methodological principles for transverse webs structural design as applicable to cargo tank area of double hull oil tankers

2020 ◽  
Author(s):  
К.В. Плотников
Keyword(s):  
Design Process ◽  
Structural Design ◽  
Design Procedure ◽  
Direct Analysis ◽  
Design Parameters ◽  
Element Analysis ◽  
Structural Rules ◽  
Functional Relations ◽  
Oil Tankers ◽  
Double Hull

Статья посвящена вопросам проектирования поперечных танкерных рам крупнотоннажных нефтеналивных судов, размеры корпусных конструкций которых должны соответствовать требованиям Общих Правил МАКО (CSR). Требования Правил CSR можно разделить на общие нормативные предписания аналитико-эмпирического характера (prescriptive-требования) и требования к выполнению проверочных расчётов (в первую очередь с использованием МКЭ). В работе рассмотрены алгоритмы проектирования поперечных рам нефтеналивных судов в соответствии с prescriptive requirements, а также предложена методика и алгоритм проектирования таких конструкций, включающие и МКЭ-анализ, которые могут использоваться в практике конструкторских бюро. Приведено обоснование необходимости анализа и обобщения проектных решений в части рамных конструкций на реальных судах, которые могут быть использованы при разработке специализированного программного обеспечения. Поскольку напряжённо-деформированное состояние рамной конструкции зависит от соотношения характеристик изгибной жесткости составляющих её балок, целесообразным является построение алгоритма проектирования, частью которого является решение оптимизационно-поисковой задачи определения требуемых размеров конструкции. Ограничения такой задачи должны формироваться на основе общих требований CSR. В тексте приведено описание нормативных требований и основные их особенности. Кратко описаны возможные варианты постановки задачи и соображения о программной реализации её решения. The paper deals with principal considerations of double-hull oil tankers primary supporting members (PSM) structural design, which meets the requirements of Common Structural Rules (CSR). The algorithms of structural design procedure for different typical arrangements of tankers are considered in the paper. The study shows main features of structural design process that lead to complexity of functional relations. As CSR requirements consist of prescriptive requirements and direct analysis requirements (that usually means finite element analysis) the suggested algorithms include both of these stages. The text explains the need of statistical data of existing designs collecting. Such data includes ratios between required and actual web depths, scantlings of brackets, ratios between moments of inertia of PSM and some others. This data can be used in structural design process and form the limitations of design parameters. As shear forces and bending moments in primary supporting members depend on ratios of its bending stiffness and relation between design parameters are rather complicated it is appropriate to use mathematical programming models, which present a decision support instrument. There are many ways of formulation and implementation of structural design task, and the paper gives general considerations about it. The brief review of previous contributions on this subject is also given.

Collision-Accidental Limit States Performance of Double-Hull Oil Tanker Structures: Pre-CSR versus CSR Designs

2009 ◽  
Vol 46 (04) ◽  
pp. 183-191
Author(s):  
Jeom kee Paik ◽  
Jae Hyung Park ◽  
Emmanuel Samuelides
Keyword(s):  
Finite Element ◽  
Structural Design ◽  
Limit State ◽  
Nonlinear Finite Element ◽  
Structural Performance ◽  
Limit States ◽  
Oil Tankers ◽  
Double Hull ◽  
The Impact ◽  
Oil Tanker

To mitigate the impact of consequences of ship collisions in terms of health, safety, and the environment, it has been made mandatory that hull structures of all oil tankers have double sides and double bottoms. In recent years, International Association of Classification Societies (IACS) has developed Common Structural Rules (CSR) for structural design of double-hull oil tankers on the basis of limit states, together with the traditional approach using the allowable working stress that has been a basis of pre-CSR. The application of CSR may result in some differences in terms of structural performance, among other aspects. The main objective of the present paper is to investigate the structural performance of CSRdesigned tankers associated with ship collisions. This aspect might be interesting, although CSR are not intended specifically to improve collision performance. As an illustrative example, an AFRAMAX-class double-hull oil tanker structure with same deadweight designed by both pre-CSR and CSR methods is studied by comparing their collision energy-absorption capabilities as obtained by nonlinear finite element methods. It is found that the collision performance of the CSR design could be improved by 5% to 25% compared with that of the pre-CSR design, depending on the accidental limit state criteria. However, it is concluded that the strength performance of the CSR vessel is similar to that of the pre-CSR vessel in terms of collision-accidental limit states, considering the uncertainties involved in conjunction with collision scenarios and nonlinear finite element method modeling techniques. Although the present study deals with some very specific scenarios of collisions, the insights and conclusions developed will still be useful for recognizing a structural design trend related to collision-accidental limit states

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