Application of the IACS Common Structural Rules for Oil Tankers to FPSOs

2007 ◽  
Author(s):  
R.J. Bamford ◽  
G. Stewart
Author(s):  
Sanjay P. Singh ◽  
Anant Lal ◽  
Sharad S. Dhavalikar

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.


2014 ◽  
Author(s):  
Wu Jiameng ◽  
Wang Gang ◽  
Cai Shijian

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.


2015 ◽  
Author(s):  
Wu Jiameng ◽  
Cai Shijian ◽  
Wang Weifei

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.


Author(s):  
Jeom Kee Paik ◽  
Bong Ju Kim ◽  
Jung Kwan Seo

The aim of the present paper is to evaluate the ultimate limit state performance of an AFRAMAX-class hypothetical double hull oil tanker structure designed by IACS CSR (Common Structural Rules) method, compared with the same-class/type tanker structure designed by IACS pre-CSR method. The ultimate strengths of stiffened plate structures in deck and bottom parts under combined in-plane and out-of-plane actions, and hull girder against vertical bending moment, are computed for the two designs, and the resulting computations are compared. ALPS/ULSAP program is used for the ultimate limit state assessment of stiffened plate structures, while ALPS/HULL program is employed for the progressive hull collapse analysis. ANSYS nonlinear FEA method, which uses more refined technology, is also used for the same purpose. The insights and developments obtained from the present study are addressed.


Author(s):  
Enrong Qi ◽  
Weicheng Cui

Based on long-time theoretical and experimental work in authors group, assessment methods of ultimate strength of ship hulls are analyzed and improved. Nonlinear finite element analysis method (FEM), idealized structural unit method (ISUM), simplified method (SM) and analytical method (AM) are integrated into a software system of direct calculations of large tankers. Using this software system, a comparative calculation is performed on ultimate hull girder strength of a 300,000dwt double hull tanker and the calculation results are also compared with the single step procedure of Common Structural Rules for double hull tankers (JTP CSR).


2020 ◽  
Vol 36 (03) ◽  
pp. 171-180
Author(s):  
Mesbah Sayebani ◽  
Abdolhossein Mohammadrahimi ◽  
Hossein Khoshdel Looyeh

Cost and weight optimization in ship construction are usually investigated in the form of a multiobjective optimization problem. So far, many studies have been carried out to achieve various types of existing optimization objectives and different tools have been developed. Most of the studies in the field of structural optimization have focused on comparing the available optimization algorithms. In this study, a rule-based tool is developed based on the Common Structural Rules (CSRs), which despite its simplicity in application, provides high capabilities in producing an optimal solution. In the developed tool, structural analysis of serviceability limit state is performed by using the relationships of CSRs. The computational tool is created by MATLAB software (Mathworks, Natick, Massachusetts), and the optimization technique is a genetic algorithm. The performance of the computational tool is evaluated by analyzing the midship section of a chemical tanker. In the optimization procedure, weight and cost are assumed to have the same importance. From the results of the developed tool, all components of the weight and cost of ship construction decreased in the optimal solution relative to the initial design.


2005 ◽  
Author(s):  
Gary E. Horn

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.


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