• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.348-355
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• 2000

The characteristics on non linear behavior and the failure mechanism of RC space frame structure serving railway under seismic action have been investigated by numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and RC frame elements with fibers are employed. Fibers are characterized as RC one and PL one to distinguish different energy release after cracking. Due to deviation of mass center and stiffness center of entire structure the complex behavior under seismic action is shown. The excessive shear force is concentrated on the pier beside flexible one relatively, which leads to failure of bridge concerned.

• Structural Engineering and Mechanics
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• 제9권2호
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• pp.209-214
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• 2000

The main purpose of this paper is to develop the results introduced in Artan (1996) and to find a general nonlocal linear elastic solution for Boussinesq problem. The general nonlocal solution given Artan (1996) is valid only when the distance to the boundary is greater than one atomic measure. The nonlocal stress field presented in this paper is valid for the whole half plane.

• Structural Engineering and Mechanics
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• 제9권1호
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• pp.37-50
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• 2000

Very few studies on orthotropic circular disks or rings under diametrical loadings are conducted because of difficulties in treatment. This paper shows analytical solutions and gives the distributions of stresses and displacements by using Lekhnitskii's complex variable method. Several numerical results are shown by graphical representation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.157-161
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• 1996

In the geometric accuracy, most of studies have been concentrated on the analysis of the geometric error, or a control path of grinding using the value of measured geometric error. In this paper, by using the value of measured motor current through hall sensor, detection of the geometric error have been accomplished, and in-process control path of grinding for improvement geometric accuracy, too.

• 산업경영시스템학회지
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• 제18권36호
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• pp.113-120
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• 1995

Much of the past work regarding repairable item stockage has concentrated on the development of models and policies for systems in steady state. However, there are important situations in which the transient behavior is most important. A dramatic example of this is the potential dynamic behavior exhibited by demands and service in the deployment of an Air Force squadron at the onset of a conflict. The purpose of this paper is to derive some probability distributions necessary for providing an integrated approach for a multi-echelon inventory system with nonstationary demands and service rates.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.269-272
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• 2006

The anchorage zone of prestressed concrete members is a critical region where a large concentrated force due to prestressing by tendons is introduced. In this study, the ACI, AASHTO LRFD, CEB-FIP design criteria and the nonlinear strut-tie model approach are applied to the ultimate strength analysis of simple anchorage zones of 18 post-tensioned concrete members tested to failure. From the result of ultimate strength analysis, the advantages and disadvantages of each method are compared and discussed.

• 한국전자통신학회논문지
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• 제8권8호
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• pp.1241-1246
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• 2013

현재 일반적인 반송 장치에서는 전기자를 반송 경로 전장에 배치하는 지상 1차측 시스템이 적용되고 있다. 하지만 이러한 시스템을 장거리 반송 장치에 적용하면 초기 설치비용과 제작시간이 상승하는 문제점이 발생한다. 이러한 문제점을 해결하기 위해 전기자를 분산시켜 배치하는 방식이 제시되고 있다. 하지만 전기자 분산배치 방식은 전기자가 존재하지 않는 구간에서 외란 발생 시 가동자가 정지할 수 있으며 이 때 전기자에 의한 제어가 불가능하게 되어 가동자를 이동 시킬 수 없는 문제점을 내재하고 있다. 따라서 이러한 문제점을 해결하기 위한 전기자 간격 결정이 매우 중요하다. 또한 전기자를 분산배치 할 경우 단부가 발생하게 된다. 이는 가동자가 전기자에 진입 또는 반출 시에 코깅력을 크게 발생시켜 추력 맥동의 원인이 되며, 소음과 진동을 발생시키므로 저감하여야 한다. 따라서 본 논문에서는 전기자를 분산 배치함에 따라 존재하는 단부 코깅력을 유한요소법을 이용한 2-D 수치해석을 통해 파악하고 이를 최소화하기 위한 전기자 간격을 도출하고자 한다.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1428-1435
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• 2006

A slightly curved crack with an eigenstrain is considered. Solutions for a slightly curved crack in a linear isotropic material under asymptotic loading as well as for a slightly curved crack in a linear isotropic material with a concentrated force are obtained from perturbation analyses, which are accurate to the first order of the parameter representing the non-straightness. Stress intensity factors for a slightly curved crack with an eigenstrain are obtained from the perturbation solutions by using a body force analogy. Particular attention is given to the crack path stability under mode I loading. A new parameter of crack path stability is proposed for a crack with an eigenstrain. The path stability of a crack with steady state growth in a transforming material and a ferroelectric material is examined.

• 대한기계학회논문집A
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• 제21권9호
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• pp.1385-1391
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• 1997

An analysis is presented on the stability of an elastic cantilever column subjected to a concentrated follower force as to the influence of the elastic restraint and a tip mass at the free end. The elastic restraint is formed by the rotatory springs. For this purpose, the governing equations and boundary conditions are derived by using Hamilton's principle, and the critical flutter loads and frequencies are obtained from the numerical evaluation of the eigenvalue functions of the considered system.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.323-326
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• 2005

Although many structures. with high strength concrete have been recently constructed, the flexural behavior of reinforced and prestressed concrete beams with high strength concrete is not exactly defined. This paper presents an experimental study on the flexural strength of the high strength concrete beams. Five large scale beams simply supported were tested and measured. Each beam was loaded by two symmetrical concentrated loads applied at 1.25m from the center of span. The concrete strength, the prestressed force and longitudinal tensile reinforcement ratio vary from beam to beam. From the experimental tests, the flexural strength from tests is larger than the nominal flexural strength of codes. Moreover, the initial crack-load is affected by the prestressed force and the crack width and spacing are controlled by the longitudinal tensile reinforcement ratio.