• 대한기계학회논문집A
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• 제32권6호
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• pp.465-473
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• 2008

Type II compressed natural gas(CNG) storage vessels for automobiles have been acknowledged for their excellence and have recently become established in local regions. Their supply is not only to automakers in Korea such as Hyundai Motors but they are being increasingly exported. Although the available products have undergone safety evaluations and are certified by an authorized institution they are still short of the optimal design that is possible for such storage vessels. This research investigates the shape and thickness of the dome with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. CNG storage vessels can be largely divided into 3 parts namely, the hear part, the cylinder part and the dome part. The head part is designed by means of a hot spinning process and this method is safer than that used in the design of the dome part even though its shape is similar. The thickness of the liners and reinforcing materials was optimized based on the requirements of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for Type II CNG storage vessels, is proposed by a process of review and analysis of various existing shape, and then conducting a structural stability evaluation to ensure the optimal design plan.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.93-100
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• 1998

The basic systems of spatial structures such as shells, membrane, cable-nets and tensegrity structure have been developed to create the large spaces without column. These structures may have large freedom in scale and form, and especially tensegrity structures are received much attention from the view points of their light weight and aesthetics. But There re some difficulties concerning structural stability, surface formation and construction method. One of the way to solve these problems reasonably is a combination of tensile members and rigid members. A structural system based on this concept is referred to as the "HTS ( Hybrid Tension Structure )". This is a type of flexible structural system which is unstable initially, because the cable material has little initial rigidity. As cable - dome hybrid structures is a type of HTS, the initial stress for the self- equilibrated system having stable state have to be introduced. To determine initial stress having stable state, the shape finding analysis is required before the stress - deformation analysis. In this paper, the primary objective is to derive the nonlinear finite element formula of cable and truss members considering geometric nonlinearity for shape finding of cable-dome, and to propose the method to decide the initial stress by the shape analysis of cable-dome hybrid structure with the self-equilibrated state.

• 대한기계학회논문집
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• 제18권3호
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• pp.707-715
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• 1994

This study presents thickness optimization for the pressure vessel domes subject to internal pressure and axial force simultaneously. The considered typical pressure vessel domes are ellipsoidal and tori-spherical domes with skirt and nozzle part. These pressure vessel domes under loading have higher stress concentration on geometric discontinuity parts. Therefore, thickness optimization of axi-symmetric pressure vessel domes is essentially concerned on minimizing this stress concentration. The objective function is minimization of weight of pressure vessel dome. The design variable is thickness of dome and cylinder. Considered constraint is Von Mises equivalent stress. In the optimization procedure, ANSYS code is used. The equivalent and hoop stress of original shape domes are compared with those of optimal shape domes. And optimal thicknesses for pressure vessel domes are presented.

• Steel and Composite Structures
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• 제30권1호
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• pp.47-55
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• 2019

The aim of this paper is to present new and an efficient optimization algorithm called Jaya for the optimum mass of braced dome structures with natural frequency constraints. Design variables of the bar cross-section area and coordinates of the structure nodes were used for size and shape optimization, respectively. The effectiveness of Jaya algorithm is demonstrated through three benchmark braced domes (52-bar, 120-bar, and 600-bar). The algorithm applied is an effective tool for finding the optimum design of structures with frequency constraints. The Jaya algorithm has been programmed in MATLAB to optimize braced dome.

• 한국공간구조학회논문집
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• 제12권1호
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• pp.59-68
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• 2012

대공간 구조시스템의 하나인 스페이스 프레임 구조는 종횡의 부재가 3차원적으로 연결되어 입체적으로 외부 힘에 저항하는 구조로써 높은 강성을 갖는다. 또한 균등한 응력 분담이 가능하도록 설계되는 스페이스 프레임 고유의 역학적 특성에 기인하여 경량화가 가능하다. 스페이스 프레임의 구조안정 문제는 구조물의 여러 가지 조건에 따라 결정되며 매우 중요하다. 본 연구에서는 기하학적 형태에 따른 래티스 돔의 동적구조불안정 특성을 알아보기 위해 2-자유 절점 구조물을 통해 스페이스 프레임의 붕괴 메터니즘을 파악하고, 기하학적 형태에 따라 Star Dome, Parallel Lamella Dome, 3-Way Grid Dome을 모델로 선택하여 동일레벨의 주기성이 없는 STEP 하중에 의한 동적외력 하에서의 라이즈-스팬(${\mu}$)비 및 형상불완전에 따른 불안정 거동 특성을 알아본다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.881-882
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• 2010

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.204-209
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• 2000

This paper suggests that post-tensioned and dome-shaped space truss formed by post-tersionong is easy to fabricate in construction process. In particular, a laboratory model is used to show how a flat space truss system can be transformed into a dome-shaped space truss by means of post-tensioning. There are some diserpancy in vertical displacement of the dxperiment and theoretical analysis for space truss. Nonlinear analysis is used to predict the final shape shape of the space truss, the experiments tndicates that this construction method can offer economy over traditional methods. In addition, the analysis indicates that when all the sxisting mechanisms are controlled, the nonlinear finite element method is more reliable way to predict the shape of the dome-shaped space truss than the linear analysis.

• 한국강구조학회 논문집
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• 제13권5호
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• pp.587-597
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• 2001

연속체 쉘을 이산화한 구조시스템은 돔형 구조물을 만들기 위해 많이 이용되고 있으며, 이러한 구조물은 하중레벨이 어느 임계값에 도달하면 구조물의 형상에 따라 뜀좌굴(snap-through) 또는 분기좌굴(bifurcation)에 의한 불안정 현상이 일어난다. 케이블 돔의 구조거동 특성은 초기장력 및 외력에 다라 비선형성이 강하게 나타나며 또한 초기조건에 매우 민감하게 반응한다. 본 연구에서는 케이블 돔의 불안정 문제를 파악하기 위해 Geiger 모델을 대상으로 하여 초기 장력도입에 의한 형상결정 문제를 다루고 이를 이용하여 완전형상 및 초기형상 불완전을 도입하여 외력에 의한 불안전성현상을 규명한다.

• 한국공간구조학회논문집
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• 제12권2호
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• pp.109-118
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• 2012

주기성을 가진 하중하에서의 거동은 스텝하중하에서의 거동과는 다른 거동을 보일 것이라 예상된다. 본 연구에서는 기하학적 형태에 따른 래티스 돔 구조물을 정현파 하중에서의 동적구조불안정 특성을 알아본다. 대공간 구조시스템의 하나인 스페이스 프레임 구조는 종횡의 부재가 3차원적으로 연결되어 입체적으로 외부 힘에 저항하는 구조로써 높은 강성을 갖는다. 또한 균등한 응력 분담이 가능하도록 설계되는 스페이스 프레임 고유의 역학적 특성에 기인하여 경량화가 가능하다. 스페이스 프레임의 구조안정문제는 구조물의 여러 가지 조건에 따라 결정되고 매우 중요한 사항이다. 따라서 기하학적 형태에 따라 Star Dome, Parallel Lamella Dome, 3-Way Grid Dome을 모델로 선택하여 라이즈-스팬(${\mu}$)비 및 형상불완전에 따른 불안정 거동 특성을 알아본다. 전체적으로 래티스 돔 구조물은 비감쇠 보다 감쇠를 도입한 경우 동적 좌굴하중에 대한 효율이 높아짐을 알 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.338-343
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• 2008

Fracture characteristics of plates and dome shapes for machinable glass ceramics using compressed shock wave. Machinable glass ceramics have been considered as a promising candidate material for the dome port cover of air breathing engine. This part of the air breathing engine has an important role separating solid and liquid fuel, and needs the frangible characteristics whereby the fracture of a part should not affect the internal components of combustion. The objective of this study are to evaluate the fracture pressure and phenomena of separated membrane using a shock tunnel. The experimental apparatus consists of driver, a driven section and a dump tank. The used material is machinable glass ceramic from Corning company. Specimens are used 3, 4.5 and 6mm thickness with plates and dome shapes. It is expected that the results obtained from this study can be used in the basic data for the dome port cover design of an air breathing engine.