• 한국전산구조공학회논문집
• /
• 제26권1호
• /
• pp.89-97
• /
• 2013

비정형 초고층 건물의 계획 및 시공이 늘어남에 따라 이 연구에서는 프로토타입 모델에 대한 시공단계해석의 적용을 통하여 비정형 초고층 건물의 시공 중 구조적 거동을 분석하고자 하였다. 비틀림 초고층 건물을 대상으로 횡력저항시스템, 비틀림각도, 공법 조건에 따른 총 18개의 모델을 선정하였다. 횡력저항시스템으로는 다이아그리드 시스템과 가새튜브 시스템을 적용하였으며, 각 횡력저항시스템별로 $0^{\circ}$, $1^{\circ}$, $2^{\circ}$ 비틀림각도를 갖는 세 가지 평면 형태와 외곽 튜브와 내부 골조의 시공순서에 따른 세 가지 공법을 가정하였다. 시공 중인 초고층 건물의 구조적 성능은 시공단계해석의 횡변위 결과를 통하여 분석되었으며, 골조 공기와 최대 양중량과 같은 시공성능이 함께 비교되었다.

• 한국터널지하공간학회 논문집
• /
• 제6권4호
• /
• pp.279-290
• /
• 2004

이 논문은 I-단면 곡선강지보 (curved steel rib)의 등분포 하중 하에서, 비틀림 (warping)을 포함한, 외평면 (out-of-plane)의 안정성을 해석하였다. 미분구적법 (differential quadrature method, DQM)을 이용하여 다양한 경계조건, 굽힘각 (opening angles)과 강성매개변수 (stiffness parameter)에 따른 임계하중 (critical loads) 및 임계하중 매개변수 (dimensionless buckling parameter)를 계산하였고, Differential quadrature method (DQM)의 해석결과를 타 이론과 비교 분석 하였다. 또한 두 경계조건 (고정-고정, 고정-단순지지)하에서의 새로운 결과를 제시하였고, DQM을 이용한 곡선강지보의 좌굴해석은, 비교적 적은 요소 (grid points)를 사용하고도, 타 이론에 의한 해석적 결과에 비해 정확성과 안정성을 보여주었다.

• Advances in concrete construction
• /
• 제14권5호
• /
• pp.317-330
• /
• 2022

This paper investigated computationally and experimentally the interaction here between a notch as well as a micropore under uniaxial compression. Brazilian tensile strength, uniaxial tensile strength, as well as biaxial tensile strength are used to calibrate PFC2d at first. Then, uniaxial compression test was conducted which they included internal notch and micro pore. Experimental and numerical building of 9 models including notch and micro pore were conducted. Model dimensions of models are 10 cm × 10 cm × 5 cm. Joint length was 2 cm. Joints angles were 30°, 45° and 60°. The position of micro pore for all joint angles was 2cm upper than top of the joint, 2 cm upper than middle of joint and 2 cm upper than the joint lower tip, discreetly. The numerical model's dimensions were 5.4 cm × 10.8 cm. The fractures were 2 cm in length and had angularities of 30, 45, and 60 degrees. The pore had a diameter of 1 cm and was located at the top of the notch, 2 cm above the top, 2 cm above the middle, and 2 cm above the bottom tip of the joint. The uniaxial compression strength of the model material was 10 MPa. The local damping ratio was 0.7. At 0.016 mm per second, it loaded. The results show that failure pattern affects uniaxial compressive strength whereas notch orientation and pore condition impact failure pattern. From the notch tips, a two-wing fracture spreads almost parallel to the usual load until it unites with the sample edge. Additionally, two wing fractures start at the hole. Both of these cracks join the sample edge and one of them joins the notch. The number of wing cracks increased as the joint angle rose. There aren't many AE effects in the early phases of loading, but they quickly build up until the applied stress reaches its maximum. Each stress decrease was also followed by several AE effects. By raising the joint angularities from 30° to 60°, uniaxial strength was reduced. The failure strengths in both the numerical simulation and the actual test are quite similar.

• Advances in concrete construction
• /
• 제13권 2호
• /
• pp.199-213
• /
• 2022

Experimental and discrete element approaches were used to examine the effects of F shape non-persistent joints on the failure behaviour of concrete under uniaxial compressive test. concrete specimens with dimensions of 200 cm×200 cm×50 cm were provided. Within the specimen, F shape non-persistent joint consisting three joints were provided. The large joint length was 6 cm, and the length of two small joints were 2 cm. Vertical distance between two small joints change from 1.5 cm to 4.5 cm with increment of 1.5 cm. In constant joint lengths, the angle of large joint change from 0° to 90° with increments of 30°. Totally 12 different models were tested under compression test. The axial load rate on the model was 0.05 mm/min. Concurrent with experimental tests, numerical simulation (Particle flow code in two dimension) were performed on the models containing F shape non-persistent joint. Distance between small joints and joint angles were similar to experimental one. the results indicated that the failure process was mostly governed by both of the Distance between small joints and joint angles. The axial loading rate on the model was 0.05 mm/min. The compressive strengths of the samples were related to the fracture pattern and failure mechanism of the discontinuities. Furthermore, it was shown that the compressive behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the joint angle. In the first, there were only a few acoustic emission (AE) hits in the initial stage of loading, and then AE hits rapidly grow before the applied stress reached its peak. Furthermore, a large number of AE hits accompanied every stress drop. Finally, the failure pattern and failure strength are similar in both approaches i.e., the experimental testing and the numerical simulation approaches.

• 한국해양공학회지
• /
• 제26권4호
• /
• pp.15-22
• /
• 2012

In this research, the relationship between the bow shape and green water phenomenon on the bow deck of an FPSO was studied using an experimental method. A 140,000 DWT FPSO was used as the objective hull form in the present research. The incident waves were regular types. The heights were 1.0 and 1.5 times the freeboard, and the length was equal in size to LBP. The wave heights and pressures on the deck were measured in experiments. Model tests were performed to determine the effects of bow flare angles, bow shapes, and a forecastle deck. The free heave and pitch conditions were applied to the models in these experiments. From the results of the model tests, an optimized bow shape was designed, which was found to decrease the green water impact loading. The results of this research could be used as fundamental data in the design of a bow shape.

• Composites Research
• /
• 제13권2호
• /
• pp.51-60
• /
• 2000

본 논문에서는 두께 방향의 와인딩 각도 변화를 고려한 필라멘트 와인딩 된 압력탱크의 해석을 수행하였다. 두께방향의 와인딩 각도를 고려하기 위하여 임의의 맨드릴 표면에 대한 필라멘트 와인딩 궤적을 찾아낼 수 있는 semi-geodesic path식을 도입하였다. 필라멘트 와인딩 된 압력탱크의 유한요소 모델링을 위하여 3차원 적층고체요소를 사용하였으며, 상용프로그램ABAQUS를 이용하여 유한요소해석을 수행하였다. 해석에서는 모재 파손에 의한 강성저하를 모사하기 위하여 재료 비선형성을 고려하였으며, 이를 위하여 각 하중 증분 후에 섬유 수직방향 응력을 모재의 인장강도와 비교하는 최대응력파손이론을 도입하였고, 파손이 일어난 층에 대해서 모재 방향의 재료 상수를 1/10로 저하시켰다. 그리고, 점진적 파손해석을 수행한 결과를 문헌에 주어진 실험데이터와 비교하였다.

• 한국항공우주학회지
• /
• 제31권8호
• /
• pp.77-84
• /
• 2003

액체로켓용 터보펌프 터빈 블레이드-디스크의 구조 및 진동 해석이 설계점에서의 구조 강도 및 동특성을 고찰하기 위하여 수행되었다. 터보펌프의 높은 회전 속도로 인하여 구조 해석시 원심력 영향이 주의깊게 고려되었다. 극심한 온도 분포에 따른 열하중 또한 터빈 블레이드-디스크에 작용하는 외부하중으로 고려되었다. MSC/NASTRAN DMAP Alter를 이용한 3차원 유한요소법이 주기 대칭 구조 해석에 적용되었다. 회전 속도에 따른 구조 동특성의 고찰을 위하여 블레이드간 위상차가 고려되었다. 수치해석을 통하여 원심력과 열하중이 터빈 블레이드-디스크에 미치는 영향을 고찰하였다.

• Structural Engineering and Mechanics
• /
• 제68권2호
• /
• pp.193-201
• /
• 2018

This paper describes an experimental study on the seismic performance of steel reinforced concrete (SRC) T-shaped columns. The lateral loads were applied along the web of the column with different loading histories, such as monotonic loading, mixed loading of variable amplitude cyclic loading and monotonic loading, constant amplitude cyclic loading and variable amplitude cyclic loading. The failure modes, load-displacement curves, characteristic loads and displacements, ductility, strength and stiffness degradations and energy dissipation capacity of the column were analyzed. The effects of loading history on the seismic performance were focused on. The test results show that the specimens behaved differently in the aspects of the failure mode subject to different loading history, although all the failure modes can be summarized as flexural failure. The hysteretic loops of specimens are plump, and minimum values of the failure drift angles and ductility coefficients are 1/24 and 4.64, respectively, which reflect good seismic performance of SRC T-shaped column. With the increasing numbers of loading cycles, the column reveals lower bearing capacity and ductility. The strength and stiffness of the column with variable amplitude cyclic loading degrades more rapidly than that with constant amplitude cyclic loading, and the total cumulative dissipated energy of the former is less.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제12권2호
• /
• pp.79-90
• /
• 2012

The torsion beam type of rear suspension has been adopted by most manufactures of small to medium front wheel drive passenger cars. Previous studies analyzed only the load characteristics of CTBA(the coupled torsion beam axle)'s components. This paper analyzed the results of measurement after measuring loads and displacements, angles when a car equipped with the coupled torsion beam axle is driving in various roads. The most important durability factors for CTBA part are the force and direction of rear CTBA trailing arm. If there are design changes, it was difficult to make a sensor and install each time for measuring the trailing arm forces. After analyzing the loading histories between body and chassis, we developed the transformation matrix that can be converted to mutual force. This paper also deals with the analysis of the force behavior through the analysis of the influence and correlation between the body and chassis parts of cars.

• Steel and Composite Structures
• /
• 제33권6호
• /
• pp.767-776
• /
• 2019

In this article, a simple and robust multi-objective assessment method to control design angles and node positions connected among steel outrigger truss members is proposed to approve both structural safety and economical cost. For given outrigger member layouts, the present method utilizes general-purpose prototypes of outrigger members, having resistance to withstand lateral load effects directly applied to tall buildings, which conform to variable connecting node and design space deposition. Outrigger layouts are set into several initial design conditions of height to width of an arbitrary given design space, i.e., variable design space. And then they are assessed in terms of a proposed multi-objective function optimizing both minimal total displacement and material quantity subjected to design impact factor indicating the importance of objectives. To evaluate the proposed multi-objective function, an analysis model uses a modified Maxwell-Mohr method, and an optimization model is defined by a ground structure assuming arbitrary discrete straight members. It provides a new robust assessment model from a local design point of view, as it may produce specific optimal prototypes of outrigger layouts corresponding to arbitrary height and width ratio of design space. Numerical examples verify the validity and robustness of the present assessment method for controlling prototypes of outrigger truss members considering a multi-objective optimization achieving structural safety and material cost.