• Structural Engineering and Mechanics
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• 제16권1호
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• pp.1-15
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• 2003

This paper proposes a new method for the preliminary design of cable-stayed bridges that belong to the radial system subjected to static loads (self weight, traffic loads, concentrated loads, etc). The method is based on the determination of the each time existing relation between the tension forces of the cables and the corresponding bridge-deck deformations, and can be extended on any type of cable layout (fan, parallel, or mixed system). Galerkin's method is used for the final determination of the cable stresses and the bridge deformation. The determination of the equation, which gives the forces of the cables in relation to the deck's configurations, permits us to convert the problem to the solving of a continuous beam without cables.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.73-78
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• 2004

For the preliminary stages of ship design it is necessary to develop a basic design, which specifies the main particulars of the vessel. based on the requirements given by the owner. An efficient design enables the shipyard to make a rough estimate of the construction costs and to put forward a favourable quote during the call for tenders. The parametric determination of the main particulars of the vessel involves the application of empirical formulae. These formulae have been created after detailed tests and research by maritime research institutions and researchers had been carried out. Here, the design of a medium sized Bulk Carrier (26000t dwt) with a service speed of 17 knots for carrying rice and rock phosphate has been illustrated. Medium sized Bulk Carriers (25,000t dwt - 50,000t dwt) are in steady demand among small shipping companies. They have a size advantage, in that port size restrictions do not affect their design tremendously. Nevertheless, structurally. they are one of the most difficult to build. During design, the rules of the maritime regulatory bodies were strictly adhered to.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 가을 학술발표회 논문집
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• pp.5-14
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• 1991

The basic rules and principles for designing structures with composite materials are briefly and intensively presented. The proposed design steps are explained. For preliminary design, use of quasi-isotropic properties is proposed. The validity of this proposal will be reported by separate papers.

• 한국항공우주학회지
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• 제50권2호
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• pp.137-146
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• 2022

선박자동식별장치(Automatic Identification System, AIS)는 선박의 정보를 자동으로 송수신하는 장치로 선박에 탑재된다. 연안 인근 선박의 AIS 정보는 지상에서 수신 가능하지만, 50해리 이상의 먼 해상으로 나가게 되면 지상과 통신이 두절되는 한계점을 가진다. 이를 해결하기 위해 AIS 수신기를 탑재한 AIS 위성을 통하여 먼 해상의 선박 정보를 지상으로 전송할 수 있다. 국내에서는 아직 AIS 위성 개발 사례가 없으며, 국내 다수의 선사는 해외의 AIS 서비스를 이용하고 있다. PNUSAT-1은 부산대학교에서 개발 중인 1U+ 큐브위성으로, 선박 모니터링을 위해 AIS 수신기를 탑재하여 선박 정보를 지상으로 전달하는 임무를 수행한다. PNUSAT-1은 임무 데이터가 텍스트 형태로 큰 용량의 데이터를 전송하지 않으므로 이에 부합하는 통신 장비, 저정밀 센서 및 구동기를 선택하였다. 본 논문에서 PNUSAT-1의 시스템 예비 설계를 수행하였으며, 임무 수행을 위한 요구사항, 운용 시나리오 및 모드 설계, 하드웨어 및 소프트웨어 선정 그리고 각 서브시스템의 예비설계를 수행하였다.

• International Journal of Concrete Structures and Materials
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• 제11권1호
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• pp.45-58
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• 2017

Recent investigations have pointed out that current code provisions specifying that the stiffness of reinforced concrete elements is strength independent, and therefore can be estimated prior to any strength assignment, is incorrect. A strength allocation strategy, suitable for preliminary structural design of medium height wall-frame dual systems, is presented for allocating strength in such buildings and estimating the dependable rigidities. The design process may be implemented by either the approximate continuous approach or the stiffness matrix method. It is based on the concept of the inelastic equivalent single-degree-of-freedom system which, the last few years, has been used to implement the performance based seismic design. The aforesaid strategy may also be used to determine structural configurations of minimum rotation distortion. It is shown that when the location of the modal centre of rigidity, as described in author's recent papers, is within a close distance from the mass axis the torsional response is mitigated. The methodology is illustrated in ten story building configurations, whose torsional response is examined under the ground motion of Kobe 1995, component KJM000.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.133-140
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• 2000

A suspension bridge with long span is distinguished by aesthetic point of view, but it is difficult to analyze the structural behaviors due to its geometric nonlinear characteristics. Futhermore, because the chance of design such special bridges is very rare, the assumption of initial dimensions of geometrical shapes and structural sections may be much difficult also. In this paper, the brief data base on the important structural dimensions of suspension bridges is constructed after the informations on existing suspension bridges are collected and classified from various texts and internet web sites. Therefore this data base may be utilized very easily by the designers who tries to design such bridges in the preliminary design step. Also the static geometric nonlinear analysis program is added to assist the designer in simple decision of safety check for assumed dimensions.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권2호
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• pp.96-103
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• 2010

A concept of preliminary design for mid-size superyachts is explored. First, the profile of a superyacht is interactively designed with the help of freeform curve functionality and graphical user interface (GUI) based interaction. The hull form is then constructed using major characteristic curves such as design waterline, deck sideline, and sections in addition to the predefined profile curve. After exterior hull modeling is done, the arrangement of significant interior spaces of all decks is carried out. A genetic algorithm is exploited to find a space arrangement by considering space fitness values, space proximity, and stairs connectivity of relevant spaces. A goal of the paper is to offer a step-by-step procedure for superyacht design from scratch or when initial information is not sufficient for complete design. For this purpose, a GUI based superyacht design system is developed. This design approach is expected to help users interactively design mid-size superyachts.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.685-686
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• 2004

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 봄 학술발표회논문집
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• pp.79-85
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• 1993

An integrated structural design system can define and process complex design information that occurs in each of the design stages for flexible cooperation. It can also reduce human error on sequential design steps: preliminary design, analysis and detailed design. Therefore, it's very important to have consistent semantic expression and procedure for structural design information that has complex relationships. In this study, we introduce the object-oriented concepts and object-oriented database thechnique that provides high level semantic expression in order to develop an integrated structural design system.

• Structural Engineering and Mechanics
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• 제27권4호
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• pp.425-438
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• 2007

Large changes in stiffness associated with cracking and yielding of reinforced concrete sections may be expected to occur during the dynamic response of reinforced concrete frames to earthquake ground shaking. These changes in stiffness in stories that experience cracking might be expected to cause relatively large peak interstory drift ratios. If so, accounting for such changes would add complexity to seismic design procedures. This study evaluates changes in an index parameter to establish whether this effect is significant. The index, known as the coefficient of distortion (COD), is defined as the ratio of peak interstory drift ratio and peak roof drift ratio. The sensitivity of the COD is evaluated statistically for five- and nine-story reinforced concrete frames having either uniform story heights or a tall first story. A suite of ten ground motion records was used; this suite was scaled to five intensity levels to cause varied degrees of damage to the concrete frame elements. Ground motion intensity was found to cause relatively small changes in mean CODs; the changes were most pronounced for changes in suite scale factor from 0.5 to 1 and from 1 to 4. While these changes were statistically significant in several cases, the magnitude of the change was sufficiently small that values of COD may be suggested for use in preliminary design that are independent of shaking intensity. Consequently, design limits on interstory drift ratio may be implemented by limiting the peak roof drift in preliminary design.