• Journal of the Society of Naval Architects of Korea
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• v.52 no.3
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• pp.265-274
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• 2015

International organizations and classification societies established rules and regulations to which shipbuilders and ship operators should comply during design, construction, even operation keeping from hazard to life of crews and ocean environment. Hence, rules and regulations could be guidelines for design and construction of ship sometimes. In practical wise, ship structure designers be predisposed to design lightest and easy-to-product structures which satisfy rules and regulations. Therefore, changes of rules and regulations are remarkably important issue to related industries. In 2006, IACS established and released Common Structural Rules for Bulk Carrier and Common Structural Rules for Double Hull Oil Tanker. These CSRs are consolidated and unified rules of class society's rules. But these two rules are different from each other. IACS has plan to release unified rule of two ship type called Harmonized Common Structural Rule for Bulk Carriers and Oil Tankers. This new rule will be effective from July 2015. Hence, bulk carrier and double hull oil tanker whose contract date is on and thereafter July 2015 should be complied with CSR-H. Therefore, it is highly important to be aware of consequences and cause of consequences with respect to CSR-H. The object of this research is to compare requirements of structure scantling in way of midship area for selected target ship according to CSRs and CSR-H and to analysis cause of deviation between two rules.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.4
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• pp.336-342
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• 2016

H-CSR(Harmonized Common Structural Rules) integrating CSR-BC(Common Structural Rules for Bulk Carriers) and CSR-OT(Common Structural Rules for Double Hull Oil Tankers) came into effect in July of 2015, so that bulk carrier and double hull oil tanker should comply with this rules. So far, several studies for trend analysis of requirements of structure scantling based on H-CSR have been carried out briskly. However, those studies are rare to apply H-CSR in actual structural design of ships, especially bulk carriers. In this study, an automated system for compartment arrangement is used to search the design case that minimizes still water bending moment(S.W.B.M) in 38k bulk carrier designed by Far East Ship Design & Engineering Co. Ltd. Also, various structural design cases are considered by changing arrangement of structural members to reduce ship weight. The SeaTrust-Hullscan software developed by Korean Register is used to perform structural design of ships based on mother ship and proper design cases are selected by user. The DSA(Direct Strength Analysis) is performed to evaluate structural safety for the yielding and buckling analysis by using MSC Nastran software. The effect of weight reduction is verified by comparison of ship weight between mother ship and the selected design cases.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.73-79
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• 2017

IACS enacted Harmonized CSR(CSR-H) to meet the IMO GBS applied from 1 July 2016. CSR-H is clearly complement and integrate than present CSR-BC & CSR-OT. One of the biggest issue in new rule is structural analysis. In CSR-H, structural analysis must carried out entire each cargo area including the aft bulkhead of the aftermost cargo hold and the collision bulkhead. Accordingly, new load and boundary conditions are present, an additional structural reinforcement is required by the structural analysis result for each cargo hold. In this study, we applied CSR-H to existing 158K DWT CLASS CRUDE OIL TANKER in order to compare and analyze the hull changes. It is useful for the application of the CSR-H to the similar vessel and helpful in finding the optimized structural design.

• Special Issue of the Society of Naval Architects of Korea
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• 2015.09a
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• pp.46-49
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• 2015

Common Structural Rules (CSR) about bulk carriers and double-hull oil tankers of International Association of Classification Societies (IACS) has been applied to ships contracted for construction since April 2006. By unifying each society's rules, the difference of opinion in the between shipyard and ship owners, classification was reduced, and CSR has been evaluated by rules the safety structure more enhanced. However, The CSR about the bulk carriers and double hull oil tankers, important design content standards, such as the local scantling calculation, static/dynamic load case and corrosion margin and etc., are different. Therefore in order to combine the CSR, the Harmonized CSR for bulk carriers and double hull oil tankers (H-CSR) was issued on 1, January, 2014, and will be apply to ships contracted for construction after 1st July 2015. It is necessary to verify the H-CSR to optimize the structural arrangement because effective date is not far off. In this study, we compared the impact by rule change for the hull girder shear strength of bulk carriers between CSR and H-CSR in respect of the yielding and buckling strength.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.161-169
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• 2015

According to SOLAS Regulation XII/6.5.3 and IMO GBS functional requirement(IMO, 2010), the structural redundancy of multi-bay stiffened panel in cargo area of bulk carrier should be provided enough in order to endure the initial design load though one bay of the stiffened panel is damaged due to plastic deformation or fatigue crack. To satisfy structural redundancy, Harmonized Common Structural Rules (hereinafter CSR-H, IACS, 2014) proposed to use 1.15 instead of 1.0 for buckling usage factor of stiffened panel in cargo area. This paper shows that buckling usage factor in CSR-H for structural redundancy is somewhat conservative considering the ultimate strength calculated by using nonlinear FEA for the damaged condition which is only one bay's plastic deformation due to colliding by weigh object like a bucket. Also, this paper presents that increasing of plate thickness only is more effective to get enough structural redundancy.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.4
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• pp.352-359
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• 2017

Because the Energy Efficiency Design Index(EEDI) came into effect in 2013, it is necessary to develop a new technology to overcome $CO_2$ emission regulations. In structural design viewpoint, lots of researches are carried out to develop eco-friendly and high fuel efficiency ships by weight reduction. By using the automated compartment arrangement system and automated structural design algorithm which were developed by the authors, new researches are performing to combine the above two systems. However, the effect of weight reduction was not significant because structural designs by using these systems for the midship part was carried out only focused on the minimum still water bending moment. In this paper, at first, good compartment arrangements which give the minimum still water bending moment and(or) shear force were chosen by using the automated compartment system. And then, influence of shear force on weight reduction was investigated by using the automated structural design algorithm considering longitudinal strength, local strength and shear strength of longitudinal members in cargo holds. Conclusively, it is necessary to consider the minimum still water bending moment and shear force simultaneously to reduce the weight of mid-sized bulk carrier. Also, good compartment arrangement which gives much more weight reduction compared with existing ship was proposed.

• Korean Journal of Computational Design and Engineering
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• v.21 no.2
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• pp.186-195
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• 2016

The finite element modeling of a ship for hull structural analysis on the basis of new harmonized common structural rules (CSR-H) is to be extended to the cargo holds in fore and after body of a ship. Unlike the parallel middle-body where the external and internal features of hull are equal along to the longitudinal direction of a ship, in fore and after body, the external and internal features of hull vary linearly or even irregularly in forms of a surface or a curve along to the longitudinal direction of a ship. Thus, it needs lots of design man-hours for the modeling for structural analysis. In order to save man-hours in initial structural design phase of a ship, the specified 3D CAD system has been adopted in shipbuilding industry. Through the interface between CAD and CAE (rule scantling and direct strength assessment), design man-hour in initial design phase can be saved even under the environment of CSR-H.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.6
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• pp.503-513
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• 2016

In order to reduce the green-house gas exhaustion, International Maritime Organization (IMO) has been reinforcing carbon gas regulations. Due to the regulations, a lot of competitions for designing Eco ship in the shipbuilding industry are progressing now. It is faced with the necessity of reducing hull weight by combining automated systems for optimal compartment arrangement with hull structural design. Most researches on optimum structural design method have been consistently in progress and applied to minimize weight and cost of mid-ship section in preliminary ship design stage based on analytical structural analysis method on fixed compartment arrangement. In order to reduce design period and to improve international technical competitiveness by shortening the period of hull structural design and enhancing design accuracy, it has been felt necessity to combine optimized compartment arrangement with optimum design of ship structure based on the international regulations and rules. So in this study, the automated design algorithm for longitudinal members has been developed to combine automated algorithm of compartment arrangement with hull structural design system for oil tanker. The SeaTrust-Hullscan software developed by Korean Register is used to perform ship structural design for mother ship and selected design cases. The effect of weight reduction is verified with comparison of ship weight between mother ship and the cases suggested in this study.