• 한국전산구조공학회논문집
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• 제23권5호
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• pp.501-507
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• 2010

본 논문에서는 중력하중 및 풍하중, 지진하중을 받는 지상 8층, 지하 3층의 RC(Reinforced Concrete) 빌딩 시공에 필요한 부재의 재료비를 줄이기 위해 중량을 감소시키는 구조 최적설계를 수행한다. 이를 위해 설계요구사항을 바탕으로 부재의 부피를 최소화하는 설계변수값을 찾기 위한 설계문제를 정식화한다. 최적설계 수행을 위해 상용 PIDO(Process Integration and Design Optimization) 툴인 PIAnO(Process Integration, Automation and Optimization)에서 제공하는 다양한 설계기법들을 이용한다. 먼저 실험계획법(Design of Experiments; DOE)을 이용하여 실험계획을 세우고, 실험점에 따라 건축분야 범용 구조해석 프로그램인 MIDAS Gen을 사용하여 구조해석을 수행한다. 그리고 해석결과를 바탕으로 각 응답에 대한 근사모델을 생성한 후 근사모델의 예측성능을 평가한다. 예측성능이 검증된 근사모델과 최적화기법을 이용하여 최적설계를 수행하고, 설계조건을 만족하면서 부재의 부피를 최소화하는 최적 설계변수값을 도출함으로서 본 논문에서 제안된 설계방법의 유효성을 보이고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.32-36
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• 2002

This paper presents the structural characteristic analysis of a centerless grinding machine with concrete bed. The centerless grinding machine is composed of grinding wheel head, regulating wheel head, concrete bed, wheel dresser and so on. Especially, the concrete bed is introduced to improve the static, dynamic and thermal characteristics of the centerless grinding machine. The structural analysis model of centerless grinding machine is constructed by the finite element method, and the structural characteristics in the design stage are estimated based on the structural deformation and harmonic response under the various testing conditions related to gravity force and directional farces

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.326-333
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• 2004

This paper presents the structural characteristics analysis of a high-speed horizontal machining center with spindle speed of 50, 000rpm and feedrate of 120m/min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motor and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guide. The structural analysis model of the high-speed horizontal machining center is constructed by the finite element method, and the validity of structural design is estimated based on the structural deformation of the high-speed horizontal machining center and spindle nose caused by the gravity and inertia forces.

• Computers and Concrete
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• 제33권2호
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• pp.195-204
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• 2024

Floor inertial forces are transferred to lateral force resisting systems through a diaphragm action during earthquakes. The diaphragm action requires floor slabs to carry in-plane forces. In precast concrete diaphragms, these forces must be carried across the joints between precast floor units as they represent planes of weakness. Therefore, diaphragm reinforcement with sufficient strength and deformability is necessary to ensure the diaphragm action for the floor inertial force transfer. In a shake table test for a three-story precast concrete structure, an unexpected local failure in the diaphragm flexural reinforcement occurred. This failure caused loss of the diaphragm action but did not trigger collapse of the structure due to a possible alternative path for the floor inertial force transfer. This paper investigates this failure event and its impact on structural seismic responses based on the shake table test and simulation results. The simulations were conducted on a structural model with discrete diaphragm elements. The structural model was also validated from the test results. The investigation indicates that additional floor inertial force will be transferred into the gravity columns after loss of the diaphragm action which can further result in the increase of seismic demands in the gravity column and diaphragms in adjacent floors.

• Earthquakes and Structures
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• 제17권5호
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• pp.511-519
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• 2019

The concrete gravity dam is one of the most important parts of the nation's infrastructure. Besides the benefits, the dam also has some potentially catastrophic disasters related to the life of citizens directly. During the lifetime of service, some degradations in a dam may occur as consequences of operating conditions, environmental aspects and deterioration in materials from natural causes, especially from dynamic loads. Cumulative Absolute Velocity (CAV) plays a key role to assess the operational condition of a structure under seismic hazard. In previous researches, CAV is normally used in Nuclear Power Plant (NPP) fields, but there are no particular criteria or studies that have been made on dam structure. This paper presents a method to calculate the limitation of CAV for the Bohyeonsan Dam in Korea, where the critical Peak Ground Acceleration (PGA) is estimated from twelve sets of selected earthquakes based on High Confidence of Low Probability of Failure (HCLPF). HCLPF point denotes 5% damage probability with 95% confidence level in the fragility curve, and the corresponding PGA expresses the crucial acceleration of this dam. For determining the status of the dam, a 2D finite element model is simulated by ABAQUS. At first, the dam's parameters are optimized by the Minitab tool using the method of Central Composite Design (CCD) for increasing model reliability. Then the Response Surface Methodology (RSM) is used for updating the model and the optimization is implemented from the selected model parameters. Finally, the recorded response of the concrete gravity dam is compared against the results obtained from solving the numerical model for identifying the physical condition of the structure.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.881-888
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• 2006

The purpose of this study is to develop a structural. analysis system of LNG pump tower structure. The system affords to build optimized finite element model and procedure of the pump tower structure. The pump tower structure is one of the most important components of LNG (liquefied natural gas) carriers. The pump tower structure is subject to sloshing load of LNG induced by ship motion depending on filling ratio. Three types of loading components, which are thermal, inertia and self-gravity are considered in the analysis. All these design and analysis procedures are embedded in to the analysis system successfully.

• Steel and Composite Structures
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• 제17권1호
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• pp.47-67
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• 2014

Due to thermal expansion, the structural behaviour of beams in steel structures subjected to temperature increase will be affected. This may result in the failure of the structural members or connection due to extra internal force in the beam induced by the thermal increase. A method to release some of the thermally generated internal force in the members is to allow for some movements at the end supports of the member. This can be achieved by making the plane of the end-plate of the connection slanted instead of vertical as in conventional design. The present paper discusses the mechanical behaviour of beams with bolted slant end-plate connection under symmetrical gravity loads, subjected to temperature increase. Analyses have been carried out to investigate the reduction in internal force with various angles of slanting, friction factor at the surface of the connection, and allowable temperature increase in the beam. The main conclusion is that higher thermal increase is tolerable when slanting connection is used, which means the risk of failure of structures can be reduced.

• Structural Engineering and Mechanics
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• 제84권5호
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• pp.591-604
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• 2022

A gravity wall combined with an anchoring lattice frame (a combined retaining structure) is adopted at a typical engineering site at Dali-Ruili Railway Line China. Where, the combined retaining structure supports a soil deposit covering on different inclined rock slopes. With an aim to investigate and compare the effects of inclined rock slopes on the response of combined retaining structure under seismic excitation, three groups of shaking table tests are conducted. The rock slopes are shaped as planar surfaces inclined at angles of 20°, 30°, and 40° with the horizontal, respectively. The shaking table tests are supplemented by dynamic numerical simulations. The results regarding the horizontal acceleration response, vertical acceleration response, permanent displacement mode, and axial anchor force are comparatively examined. The acceleration response is more susceptible to outer structural profile of combined retaining structure than to inclined angle of rock slope. The permanent displacement decreases when the inclined angle of the rock slope increases within a range of 20°-40°. A critical inclined angle of rock slope exists within a range of 20°-40°, and induces the largest axial anchor force in the combined retaining structure.

• 대한조선학회 특별논문집
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• 대한조선학회 2007년도 특별논문집
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• pp.7-13
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• 2007

The purpose of this study is to develop a structural analysis system of LNG pump tower structure. The system affords to build optimized finite element model and analysis procedure of the pump tower structure. The pump tower structure is one of the most important components of LNG (liquefied natural gas) carriers. The pump tower structure is subject to sloshing load of LNG induced by ship motion depending on filling ratio. Three types of loading components, which are thermal, inertia and self-gravity are considered in the system. All these design and analysis procedures are embedded in to the analysis system successfully.

• 무역학회지
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• 제43권2호
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• pp.1-22
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• 2018

본 연구는 OECD-WTO의 부가가치 기준 무역(TiVA) 데이터를 이용하여 경제통합이 부가가치 기준 무역에 미치는 영향을 분석하였다. 연구결과 경제통합은 회원국간의 무역을 통계적으로 유의하게 증가시키는 것을 확인하였다. 이는 전통적 의미의 최종재와 중간재뿐만 아니라 수출에서 차지하는 국내 및 외국의 부가가치 규모도 증가하는 것을 확인하였다. 아울러 경제통합이 국내 및 외국의 부가가치 무역을 증가시키는 효과가 대체로 비슷하여 총수출에서 국내부가가치가 차지하는 비중을 증가시키거나 감소시키지 않는다는 것을 확인하였다.