The Development, Implementation And Maintenance Of Iacs Common Structural Rules For Bulk Carriers And Oil Tankers

2007 ◽  
Author(s):  
G Horn ◽  
◽  
P Baumans ◽  
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):  
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.


Brodogradnja ◽  
2021 ◽  
Vol 72 (3) ◽  
pp. 81-95
Author(s):  
Špiro Ivošević ◽  
◽  
Nataša Kovač ◽  
Nikola Momčilović ◽  
Goran Vukelić ◽  
...  

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.


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.


Brodogradnja ◽  
2021 ◽  
Vol 72 (3) ◽  
pp. 81-95
Author(s):  
Špiro Ivošević ◽  
◽  
Nataša Kovač ◽  
Nikola Momčilović ◽  
Goran Vukelić ◽  
...  

To ensure the better structural integrity and maximum safety of bulk carriers in the ship design phase, an appropriate corrosion margin is introduced by the classification societies, which should enable the exploitation of ships during the projected 25-year life cycle. The new Common Structural Rules introduce even higher corrosion margin value to ensure the structural integrity of the ship. This directly affects the increase in hull weight and thus the need for more total installed power and higher fuel consumption. Higher fuel consumption results in increased emissions which directly affects environmental pollution. For these reasons, efforts are being made to introduce alternative energy sources, cleaner fuel, ship weight reduction, and the overall economic efficiency of ships. Therefore, using experimental data collected on aging bulk carriers, the paper explores the corrosion margin reduction potential considering its impact on hull weight. Assuming that the corrosive processes occur after four years of operation, a linear model that describes the percentage of plate wear as a function of the as build-in the thickness of inner bottom plates (IBP) of fuel oil tanks (FOT) located on the double bottom of aging bulk carriers, is analyzed. Over the course of 25 years, the IBP segment was monitored on 36 different ships surveys. In this way, 520 input data describing the depth of corrosion were formed. At the same time, records were kept on the mean thickness of the original metal plate, which enabled systematization of the empirical database and grouping of measured values by intervals of original plate thicknesses, and simple conversion of corrosion depth into adequate percentage values. Depth corrosion percentages were represented by standard linear models known in the literature. Based on this analysis, representative numerical and graphical results were obtained. Conclusions from the paper can assist to optimize corrosion margin and the energy efficiency of future vessels.


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