• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
• /
• pp.191-192
• /
• 2005

In this study, the ultrasonic motor which has hollowed cross type stator was designed, and the elastic body of ultrasonic motor was optimized by using a finite element analysis program(ANSYS 9.0). When the length of leg(L) of the elastic body was increased and the width of piezoceramics was decreased, the resonant frequency was increased and the displacement of contact point between the rotor and the stator was increased. However, when the length of the leg was over the 1/3 point of the width of ceramics, the displacement of the contact point was decreased, because the elastic buckle was generated in the leg.

• 한국공간구조학회논문집
• /
• 제15권4호
• /
• pp.49-56
• /
• 2015

The roof grid of single-layer space frame structure, for Energy Core of Incheon Airport Second Terminal, is very simple and aesthetic, but it is apt to buckle under external force because of mild curvature and complex shape. The object of this study is to estimate the stability of single-layer space frame structures for Energy Core of Incheon Airport Second Terminal with the analytical conditions of structural design. The results show that the buckling load of model(pin-pin, uniform load, rigid joint), that is, the most similar model to the analytical conditions of structural design. was $10.7kN/m^2$.

• 한국의류학회지
• /
• 제30권4호
• /
• pp.595-606
• /
• 2006

Benefits of breast-feeding are so well known that mothers want to breast-feed their children. However there are a few difficulties to breast-feed when they are out for the purpose of work, visit and other social activities. The exposure of the breast is one of them. With the results of 2 surveys, 6 designs were developed. The extinguishing design features were breast openings, which were developed using various fastenings such as elastic tape, buckle, zipper, velcro, snap and button. Three outer wear designs of selected breast openings were developed. These three researched designs were made of proper materials. The purpose of this study is to develop outer wears of functionality and good design for breast-feeding mothers.

• Steel and Composite Structures
• /
• 제2권6호
• /
• pp.461-474
• /
• 2002

This paper presents the experimental and theoretical results of SUS 304 stainless tubes with different diameter-to-thickness ratio (D/t ratio) subjected to pure bending creep. Pure bending creep occurs when a circular tube is bent to a desired moment and held at that moment for a period of time. It was found that the magnitudes of the creep curvature and ovalization of tube cross-section increase faster with a higher hold moment than that with a lower one. Due to continuously increasing curvature, the circular tubes eventually buckle. Finally, a theoretical form was proposed in this study so that it can be used to describe the relationship between the creep curvature and time. Theoretical simulations are compared with the experimental test data, showing that good agreement between the experimental and theoretical results has been achieved.

• Structural Engineering and Mechanics
• /
• 제13권5호
• /
• pp.533-542
• /
• 2002

This paper considers the buckling and post-buckling behavior of empty metal storage tanks under wind load. The structures of such tanks may be idealized as cantilever cylindrical shells, and the structural response is investigated using a computational model. The modeling employs a doubly curved finite element based on a theory by Simo and coworkers, which is capable of handling large displacements and plasticity. Buckling results for tanks with four different geometric relations are presented to consider the influence of the ratios between the radius and the height of the shell (R/L), and between the radius and the thickness (R/t). The studies aim to clarify the differences in the shells regarding their imperfection-sensitivity. The results show that thin-walled short tanks, with R/L = 3, display high imperfection sensitivity, while tanks with R/L = 0.5 are almost insensitive to imperfections. Changes in the total potential energy of tanks that would buckle under the same high wind pressures are also considered.

• 한국해양공학회지
• /
• 제10권2호
• /
• pp.28-34
• /
• 1996

해저면에 설치되 있는 기름 송유관에 손상이 생겨, 송유관 내부에 흐르는 기름이 유출 될경우 엄청난 환경오염 및 재난을 발생시킨다. 해저 송유관 손상에 의한 기름유출 원인은 여러가지 경우에 기인한다. 선박의 바닥이 해저면에 끌려 해저 송유관을 손상시키는 경우, 선박의 엥커에 의해 손상되는 경우, 지진에 의해 좌굴되는 경우, 자유 경간 (Free span)에 의해 좌굴 되는 경우, 송유관 수리 시 사고로 인한 유출, 송유관의 부식에 기인한 유출 등으로 나누어 질 수 있다. 어떠한 경우이든 해저 파이프 손상시, 유출된 기름의 양을 예측하고 그에 따른 적절한 대비가 필요하다. 본 논문에서는 1차 유출 및 2차 유출을 정의하여 각각의 경우에 유출량 해석 이론을 소개하였다. 또한 이 이론을 실제 경우에 응용하여 해저 송유관 손상에 의해 방출되는 기름량을 손상면적에 따라 계산하였고, 최대 유출량 산출 법을 적용하여 손상 위치에 따른 부분별 유출량 계산법을 소개하였다.

• Steel and Composite Structures
• /
• 제3권1호
• /
• pp.65-73
• /
• 2003

A higher level of engineering standard in the field of construction, is the use of prestressing in building structures. The concept of prestressing steel structures has only recently been widely considered, despite a long and successful history of prestressing concrete members. Several analytical studies of prestressed steel girders were reported in literatures, but much of the work was not studied with reference to the optimal design and behaviour of the prestressed steel plate girder. A plate girder prestressed eccentrically, will behave as a beam-column, which is subjected to axial compression and bending moment which will cause the beam to buckle out. The study of buckling of the prestressed steel plate girder is necessary for stability criteria. This paper deals with the stability of prestressed steel plate girder using concept of "Vlasov's Circle of Stability" under eccentric prestressing force.

• 대한조선학회논문집
• /
• 제32권4호
• /
• pp.87-96
• /
• 1995

본 연구에서는 샌드위치 평판이 2축 압축력을 받아 면재와 심재가 전체적으로 좌굴되는 경우를 Rayleigh-Ritz 법으로 해석하였다. 샌드위치 평판의 전체좌굴강도에 대한 경계조건의 영향을 검토하기 위하여 단순지지, 고정 및 이들의 조합상태에 놓인 평판을 고려하였으며, 심재 및 면재의 구조특성에 따른 좌굴강도의 변화도 고찰하였다.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2023년도 추계학술발표대회
• /
• pp.289-290
• /
• 2023

턴버클(turn buckle)은 컨테이너선의 컨테이너 유실을 방지하기 위한 고박 장치이다. 컨테이너선의 항해 중 발생하는 진동을 비롯한 황천과 같은 상황 등은 고박된 턴버클의 회전과 턴버클 jaw bolt의 유실을 유발시킨다. 이러한 상황이 지속적으로 누적되어 턴버클에 영향을 미치는 경우 제대로 컨테이너를 고박하지 못해 붕괴로 이어질 수 있다. 이를 방지하기 위해 턴버클의 회전 검출과 jaw bolt의 유실 여부를 yolov5를 통해 학습하여 턴버클이 회전하는 경우와 jaw bolt의 유실 여부를 실시간으로 인지한다. 이를 통해 24시간 무인으로 턴버클을 감시하는 영역이 생김으로서 선원들의 고박 감시구역이 줄어드므로 선원들에게 주어진 과도한 업무를 줄여주는데 의의를 가진다.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2009년 추계학술발표대회
• /
• pp.97-97
• /
• 2009

The use of thin plate increases due to the need for light weight in large ship. Thin plate is easily distorted and has residual stress by welding heat. Therefore, the thin plate should be carefully joined to minimize the welding deformation which costs time and money for repair. For one effort to reduce welding deformation, it is very useful to predict welding deformation before welding execution. There are two methods to analyze welding deformation. One is simple linear analysis. The other is nonlinear analysis. The simple linear analysis is elastic analysis using the equivalent load method or inherent strain method from welding experiments. The nonlinear analysis is thermo-elastic analysis which gives consideration to the nonlinearity of material dependent on temperature and time, welding current, voltage, speed, sequence and constraint. In this study, the welding deformation is analyzed by using thermo-elastic method for PCTC(Pure Car and Truck Carrier) which carries cars and trucks. PCTC uses thin plates of 6mm thickness which is susceptible to welding heat. The analysis dimension is 19,200mm(length) * 13,825mm(width) * 376mm(height). MARC and MENTAT are used as pre and post processor and solver. The boundary conditions are based on the real situation in shipyard. The simulations contain convection and gravity. The material of the thin block is mild steel with $235N/mm^2$ yield strength. Its nonlinearity of conductivity, specific heat, Young's modulus and yield strength is applied in simulations. Welding is done in two pass. First pass lasts 2,100 second, then it rests for 900 second, then second pass lasts 2,100 second and then it rests for 20,000 second. The displacement at 0 sec is caused by its own weight. It is maximum 19mm at the free side. The welding line expands, shrinks during welding and finally experiences shrinkage. It results in angular distortion of thin block. Final maximum displacement, 17mm occurs around welding line. The maximum residual stress happens at the welding line, where the stress is above the yield strength. Also, the maximum equivalent plastic strain occurs at the welding line. The plastic strain of first pass is more than that of second pass. The flatness of plate in longitudinal direction is calculated in parallel with the direction of girder and compared with deformation standard of ${\pm}15mm$. Calculated value is within the standard range. The flatness of plate in transverse direction is calculated in perpendicular to the direction of girder and compared with deformation standard of ${\pm}6mm$. It satisfies the standard. Buckle of plate is calculated between each longitudinal and compared with the deformation standard. All buckle value is within the standard range of ${\pm}6mm$.