• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.4
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• pp.437-448
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• 2000

In this study, a numerical analysis method for soil-pile interaction in frequency domain problem is presented. The total soil-pile interaction system is divided into two parts so called near field and far field. In the near field, beam elements are used lot a pile and plain strain finite elements for soil. In the far field, dynamic fundamental solution for multi-layered half planes based on boundary element formulation is adopted lot soil. These two fields are coupled using FE-BE coupling technique. In order to verify the proposed soil-pile interaction analysis, the dynamic responses of pile on multi-layered half planes are simulated and the results are compared with the experimental results. Also, various numerical analyses of piles considering different conditions of soil-pile interaction system are performed to examine the dynamic behavior of the system. It has been found that the developed method which satisfies the radiation conditions of multi-layered half planes can be applied to various structure systems effectively in frequency domain.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1-4
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• 2008

Flat plate slab has been widely used in high rise building for its remarkable advantages. However, Flat plate structures under lateral load are susceptible to punching shear of the slab-column connection. Exterior slab-column connections has an unsymmetrical critical section for eccentric shear of which perimeter is less than that of interior connection, and hence, around the connection, unbalanced moment and eccentric shear are developed by both gravity load and lateral loads. Therefore, exterior connections is susceptible to punching shear failure. For that reason, this study compare ACI 318-05 to CEB-FIP MC 90 that is based on experiment results and existing data of flat plate exterior connections. This study shows that compared to CEB-FIP MC 90 is more exact about eccentric shear stress, unbalanced moment and Both of all are not suitable in large column aspect ratio. Considering gravity shear ratio, These are suitable but design condition only consider gravity shear ratio. So these should be considered differences from change of design condition

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.11-17
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• 2003

This paper present a method of meter-out flow control for overload protection valve in full-scale airframe test. Emergency stop, which results in dump state, can be happened during full-scale airframe test by several causes. Because servo valve can't control hydraulics actuator in the dump state, pressure in cylinder chamber may rise abruptly and overload can be acted to the test article. In this paper, the procedure and technology of orifice setting are investigated to protect the test article from unexpected loads by dump. The test results show that the presented methods decrease peak loads and improve unloading characteristics of hydraulic actuators in the dump state.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.343-349
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• 2014

The dental osseointegration implant should be enough to endure occlusion load and it's required to have efficient design and use of implant to disperse the stress into bones properly. Solidworks as a finite element analysis program for modeling and analysis of stress distribution was used for the research. The simple crown model was designed on applying conjoined condition with tightening torque of 20 Ncm of a abutment screw between a cement retained implant abutment and a fixture. A $45^{\circ}$ oblique loading from lingual to buccal side on buccal cusps of crown and performed finite element analysis by 100 N of external load. The results by a analysis for stress distribution of supporting bones of fixture were as below. The von Mises stress was concentrated on the upper side of supporting compact bone regardless of the diameters and lengths of fixture, and the efficiency result of stress reduction was increase of fixture's diameter than it's length. Therefore, it's effective to use wider fixture as possible to the conditions of supporting jaw bone.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.54-58
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• 2006

There are many kinds of propellant tank for space systems, which should be designed and manufactured considering lots of conditions such as pressure of inside and outside, temperature and weight, etc. Among them, it is the one of the most important factors that the tanks could be designed to suspend and support the applied static and dynamic loads. Tank mounting, that installs and supports a tank in the structure, is a method that should be considered the rigid and tight jointing mechanism, including the manufacturing simplicity, the light weight and the economical budget. Methods and features for several propellant tank mountings are introduced in this paper with the applications for those in some foreign space program.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.137-146
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• 2002

Geomembrane, compacted clay liner, and geosynthetic clay liner (GCL) are widely used to prevent leachate from leaking to adjacent geo-environment at a municipal solid waste (MSW) landfill. Interface shear strength between GCL and geomembrane installed at a landfill side slope is important properties for the safe design of side liner or final cover systems. The interface shear strength between two geosynthetics was estimated by a large direct shear test in this study. The shear strength was evaluated by the Mohr-Coulomb failure criterion. The effects of normal stress, hydration or dry condition, and a hydration method were investigated. The test results show that the interface shear strength and shear behavior varied depending up on the level of normal stress, the type of geosynthetic combinations, and a hydration method. When GCLs were sheared after being hydrated under 6kPa loading, the results were consistent with those published by other researchers. Summaries of friction angles, normal stress and hydration condition is presented. These friction angles could be used as a reference value at a site where similar geosynthetics are installed.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.32-39
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• 2019

Sensor pods mounted on the exterior of the aircraft used for tactical missions should have a fatigue life based on the expected load spectrum during operation. For mission equipment such as the sensor pod, the frequency fatigue life prediction method which applies the dynamic vibration environment condition is preferred due to the efficiency of the analysis. In this paper, a fatigue life prediction method in the frequency domain where stress due to static and dynamic loads is synthesized based on the actual flight load spectrum is proposed. After comparison with the existing analysis method, the fatigue life of the proposed analysis method was predicted conservatively. The proposed sensor pods satisfy the requirements of the fatigue life.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.61-64
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• 2008

A combination of CFT column and RC flat plate without formworks is very effectively rapid constructions. This paper verified the lateral resisting capacity of CFT column-RC flat plate exterior connection in comparison with general RC column-flat plate connection and detected moment capacity and ductility capacity of connection according to moment-displacement ratio. We made and tested specimens which have different variables respectively and as a result derive a following conclusion. In CFT-E2 specimen a critical section was extended and maximum moment increased 20% respectively in comparison to general RC column specimen. In BME and CFT-E1 specimens generally shear governed behaviors and CFT-E2 specimen complemented with seismic band, flexure behavior region of slab was extended and also ductility ratio and energy absorptance increased.

• Journal of the KSME
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• v.44 no.6
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• pp.53-58
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• 2004

일반적으로 사용단계의 구조물은 시간이 경과함에 따라 초기의 설계, 시공상 오류에 의한 초기결함, 반복하중 그리고 취약한 환경 등 외부 조건에 노출될 경우에는 구조물 본연의 성능을 점차 상실하게 되어 심지어는 인명과 재산권을 위협하는 대형 붕괴사고를 일으키기도 한다. 따라서 구조물의 사용성을 적정 수준 이상으로 유지하기 위해서는 정기적인 점검을 통해 잔존수명을 미리 예측하여야 함은 물론, 최적의 보수시기와 보수방법을 알려줄 수 있는 시설물 모니터링시스템이 요구되고 있다. (중략)

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.445-452
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• 2002

토목 및 건축구조물에 대한 합리적이고 정확한 설계, 시공은 물론 구조물 시공후의 안전 점검, 보수ㆍ보강 등을 위한 계측은 구조물의 사용성을 항상 최적의 상태로 유지하고 구조물의 공용수명을 연장시키는데 있어 매우 중요하다. 일반적으로 사용단계의 구조물은 시간이 경과함에 따라 초기의 설계, 시공상 오류에 의한 초기결함, 반복하중 그리고 취약한 환경 등 외부 조건에 노출될 경우에는 구조물 본연의 성능을 점차 상실하게 되어 심지어는 인명과 재산권을 위협하는 대형 붕괴사고를 일으키기도 한다. (중략)