• Steel and Composite Structures
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• 제11권6호
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• pp.505-524
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• 2011

Steel girder web panels have been subjected in recent decades, to a number of experimental and numerical studies but the mechanisms that regulate the behaviour of the panels composed by two subpanels with different thickness were not deeply studied. Furthermore specific design rules regarding the estimation of the buckling coefficient for panels with variable thickness are not included in the codes even if this is a common situation particularly for steel bridge girders with beams having significant height. In this framework,this work aims to investigate buckling behaviour of steel beams with webs composed of panels with different thicknesses subjected to both in-plane axial compression and bending moment and gives some simplified equations for the estimation of the buckling coefficient.

• Structural Engineering and Mechanics
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• 제84권4호
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• pp.453-464
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• 2022

Thin plates are the most common spatially stressed members in engineering structures that bear out-of-plane loads. Therefore, it is of great significance to study the deformation performance characteristics of thin plates for structural design. By constructing 12 basic displacement and deformation basis vectors of the four-node square thin plate element, a deformation decomposition method based on the complete orthogonal mechanical basis matrix is proposed in this paper. Based on the deformation decomposition method, the deformation properties of the thin plate can be quantitatively analyzed, and the areas dominated by each basic deformation can be visualized. In addition, the method can not only obtain more deformation information of the structure, but also identify macroscopic basic deformations, such as bending, shear and warping deformations. Finally, the deformation properties of the bidirectional thin plates with different sizes of central holes are analyzed, and the changing rules are obtained.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.21-24
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• 2011

Oil Tight Bulkhead (O. T. Bulkhead) is one of the most important structural members of oil tankers in the views of vessel's strength and safety. Therefore O.T. bulkhead's strength should be sufficient against relevant loadings, which is normally verified by local scantling requirement and structural strength analysis defined in CSR (Common Structure Rules for Double Hull Oil Tankers). However, there is a weak-able situation when the vertical stiffeners are cut due to the penetration of cargo pipes through O. T. Bulkhead. In addition, CSR does not define how to prove the strength of this case. Therefore it is necessary to verify the structural adequacy in case that several vertical stiffeners are discontinued. This article intends to prove the strength of O. T. Bulkhead with five (5) vertical stiffeners discontinued due to pipes' penetration using the grillage analysis and the finite element analysis and to provide proper reinforcement.

• 대한조선학회논문집
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• 제53권6호
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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.

• 한국항해항만학회지
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• 제35권10호
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• pp.823-827
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• 2011

2016년 7월부터 강제 적용 예정인 목표기반 선박건조 기준(GBS)의 설계단계의 기능요건 중 잔류강도 평가 부분은 현재의 유조선설계, 건조 규칙인 공통구조규칙에는 아직 포함되어 있지 않은 실정이다. 기능요건에 포함된 잔류강도 부분은 충돌이나 좌초와 같은 해상사고시 발생가능한 선체손상을 고려하여 강도측면의 제한조건을 규정함으로써 사고시에도 일정부분 선박의 안전을 확보하려는 것이다. GBS에서 주로 다루고 있는 위험도에 근거하여 잔류강도를 평가하기 위해서는 다양한 손상에 대한 광범위한 평가 작업이 필요하다. 이때, 매번 비선형 유한요소해석을 수행하기보다 선체구조를 보강판 요소의 집합으로 보는 간이화된 강도 해석법의 하나인 Smith법이 유용할 것이다. 본 연구에서는 좌초사고로 인해 선저가 손상된 경우를 대상으로 Smith법을 적용하여 최종강도 평가를 수행하였으며, 3개의 화물창 구역을 모델링하여 수행한 비선형 구조해석 결과와의 비교를 통해 Smith법을 적용한 결과의 정도를 확인하였다.

• 한국CDE학회논문집
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• 제21권2호
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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.

• 대한조선학회논문집
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• 제54권4호
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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.

• 대한본초학회지
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• 제33권5호
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• pp.19-37
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• 2018

Objectives : Oryeong-san was composed of Alismatis Rhizoma, Atractylodis Rhizoma Alba, Poria Sclerotium, Polyporus, Cinnamomi Cortex, and known to have hundreds of chemical compounds. The aim of this study was to screen chemical compounds constituting Oryeong-san with the drug-likeness and oral bioavailability from the analysis of their physicochemical properties. Methods : A list of chemical compounds of Oryeong-san was obtained from TM-MC(database of medicinal materials and chemical compounds in Northeast Asian traditional medicine). To remove redundant compounds, the SMILES (Simplified Molecular Input Line Entry System) strings of each compound were identified. All of the physicochemical properties for the compounds were calculated using the DruLiTo(Drug Likeness Tool). Drug-likeness was estimated by QED(Quantitative Estimate of Druglikeness) and OB(Oral bioavailability) was checked based on the Veber's rules. Results : A total of 475 compounds were obtained by eliminating duplication among 544 compounds of 5 medicinal materials. Analysis of the physicochemical properties revealed that the most common values were MW(molecular weight) 200~300 g/mol, ALOGP(octanol-water partition coefficient) 1~2, HBA(number of hydrogen bond acceptors) 0~1, HBD(number of hydrogen bond donors) 0, PSA(polar surface area) 0~50 angstrom, ROTB(number of rotatable bonds) 1, AROM(number of aromatic rings) 0, and ALERT(number of structural alerts) 1. QED had 93% of the values between 0.2 and 0.7, and OB had 90% of the value of TRUE. Conclusions : We in this paper screened the candidate active compounds of Oryeong-san using the QED and Veber's rules. In the future, we will use the screening results to analyze the mechanism of Oryeong-san based on systems pharmacology.

• 대한조선학회논문집
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• 제50권4호
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• pp.255-261
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• 2013

This paper presents prediction of ultimate longitudinal strength of a VLCC, "Energy Concentration" for which many benchmark studies have been carried out, based on kinematic displacement method proposed by Tayyar and Bayraktarkatal (2012). Kinematic displacement theory provides semi-analytical solution of average compressive strengths for various kinds of stiffened panels. The accuracy of average compressive strengths obtained from formulas of CSR(common structural rules) for tankers and kinematic displacement method are discussed in the fore part of this paper. Hull girder ultimate strengths using Smith method are also compared for different average compressive strengths. By comparing them with other benchmark results, it is concluded that the new method provides lower bounds, because hull girder strengths under the sagging and hogging moment conditions approach nearly lower bounds.

• International Journal of Computer Science & Network Security
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• 제21권12spc호
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• pp.544-548
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• 2021

Scientific and technical development, as well as the emergence of new types of contracts, which do not have their expression in current legislation, force us to explore the issues of contract law to adapt to change. In this context, the principle of freedom of contract is fundamental, which states that each person has the right to enter into a contractual relationship at his discretion. However, such freedom is not absolute, because the freedom of one person should not violate the freedom of another. Together with the conflict of private and public interests, these phenomena are a field for the study of topical issues of theory and application of the principle of freedom of contract in practice. Research methods are philosophical, general scientific, and special scientific methods, in particular, system-structural, formal-legal, hermeneutic; methods of analysis, synthesis, etc. As a result of the research, the main characteristics of the principle of freedom of contract, its role for private law regulation of contract law are given; approaches to understanding the restriction of contract freedom are analyzed; typical examples and means of such restrictions are identified; demonstrated how contract freedom is embodied in the use of IT tools, which types of contracts are most common in the digital environment.