• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.433-439
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• 2007

The main objective of the paper is to investigate the static behavior of a prestressed concrete (PSC) girder that has been spliced with precast box segments. A 20 m long full-scale spliced PSC girder is fabricated and tested to compare its static performance against a monolithic girder. The monolithic girder has the same geometric and material properties with respect to the spliced girder. This includes infernal strain, deflections, neutral axis position, and crack patterns for both girders. The test also consists of monitoring relative displacements occurring across the joints. Both the horizontal displacement (gap) and vertical displacement (sliding) are measured throughout the loading procedure. All results have been compared to those obtained from the monolithic girder. It has been demonstrated that the spliced girder offers close behavior with respect to the monolithic girder up to the crack load. Both girders exhibits ductile flexural failure rather than abrupt shear failure at joints.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.174-181
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• 2014

Design procedure of LEG(Linear Electric Generator) is introduced by performing the time-domain analysis for the heaving motion of a floating buoy coupled with LEG. A vertical truncated buoy is selected as a point absorber and a double-sided Halbach array mover and cored slotless stator is adopted as a linear electric generator. LEG with a double-sided Halbach array mover and cored slotless stator is designed with the input data such as the heave motion velocity and wave exciting forces in time-domain. The validity of designed LEG is confirmed by performing generating-characteristic-analysis under the sinusoidal motion of a buoy, based on the numerical techniques such as FE(Finite Element) analysis. In particular, an ECM(Equivalent Circuit Method) is employed as the design tool for the prediction of generating characteristics under irregular wave conditions. Finally, we confirm that the ECM gives reasonable and fast results without sacrifice of accuracy.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.157-168
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• 2008

Statement of problem: Over the past two decades, implant supported fixed prosthesis have been widely used. However, there are few studies conducted systematically and intensively on the splinting effect of implant systems in mandible. Purpose: The purpose of this study was to investigate the changes in stress distributions in the mandibular implants with splinting or non-splinting crowns by performing finite element analysis. Materials and methods: Cortical and cancellous bone were modeled as homogeneous, transversely isotropic, linearly elastic. Perfect bonding was assumed at all interfaces. Implant models were classified as follows. Group 1: $Br{{\aa}}nemark$ length 8.5mm 13mm splinting type Group 2: $Br{{\aa}}nemark$ length 8.5mm 13mm Non-splinting type Group 3: ITI length 8.5mm 13mm splinting type Group 4: ITI length 8.5mm 13mm Non-splinting type An load of 100N was applied vertically and horizontally. Stress levels were calculated using von Mises stresses values. Results: 1. The stress distribution and maximum von Mises stress of two-length implants (8.5mm, 13mm) was similar. 2. The stress of vertical load concentrated on mesial side of implant while the stress of horizontal load was distributed on both side of implant. 3. Stress of internal connection type was spreading through abutment screw but the stress of external connection type was concentrated on cortical bone level. 4. Degree of stress reduction was higher in the external connection type than in the internal connection type.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.119-127
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• 2012

Purpose: This study was performed to compare the stress distribution pattern of abutment-fixture connection area using 3-dimensional finite element model analysis when 5 different implant systems which have internal connection. Materials and methods: For the analysis, a finite element model of implant was designed to locate at first molar area. Stress distribution was observed when vertical load of 200 N was applied at several points on the occlusal surfaces of the implants, including center, points 1.5 mm, 3.0 mm away from center and oblique load of 200 N was applied $30^{\circ}$ inclined to the implant axis. The finite element model was analyzed by using of 3G. Author (PlassoTech, California, USA). Results: The DAS tech implant (internal step with no taper) showed more favorable stress distribution than other internally connected implants. AS compare to the situations when the loading was applied within the boundary of implants and an oblique loading was applied, it showed higher equivalent stress and equivalent elastic strain when the loading was applied beyond the boundary of implants. Regardless of loading condition, the abutments showed higher equivalent stress and equivalent elastic strain than the fixtures. Conclusion: When the occlusal contact is afforded, the distribution of stress varies depending on the design of connection area and the location of loading. More favorable stress distribution is expected when the contact load was applied within the diameter of fixtures and the DAS tech implant (internal step with no tapering) has more benefits than the other design of internally connected implants.

• The Journal of the Acoustical Society of Korea
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• v.21 no.1
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• pp.73-81
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• 2002

The transmission of vibration energy through beam-plate junctions in vibration intensity analysis called power new analysis (PFA) has been studied. PFA is an analytic tool for the prediction of frequency averaged vibration response of built-up structures at medium to high frequency ranges. The power transmission and reflection coefficients between the semi-infinite beam and plate are estimated using the wave transmission approach. For the application of the power coefficients to practical complex structures, the numerical methods, such as finite element method are needed to be adapted to the power flow governing equation. To solve the discontinuity of energy density at the joint, joint matrix is developed using energy flow coupling relationships at the beam-plate joint. Using the joint matrix developed in this paper, an idealized ship stem part is modeled with finite element program, and vibration energy density and intensity are calculated.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.63-71
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• 2004

The centroid of rail doesn't coincide with the centroid of stringer on target truss bridge. If there is no eccentricity on the bridge, bending stress works only. But in the real design and execution, not only bending stress works but also torsional stress does because of it's eccentricity. So this study evaluates how much the torsional stress by eccentricity effects joint members on the bridge. We investigate the possibility to control torsional stress if we model longitudinal bracing between stringers.

• KOMUNHWA
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• no.61
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• pp.95-128
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• 2003

Shell middens, so called waste sites, are the remains made by files of wastes after the sources are used from the natural and artificial environment. The relic things, excavated in shell middens are usually found to be broken and hard to recognize the ori

• Journal of the Korean Institute of Gas
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• v.20 no.3
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• pp.73-77
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• 2016

This paper presents the displacement behavior safety of hollow shafts with an equivalent volume for various cross sectional area using a finite element method. The FEM results indicate that the hollow shafts with X-type or Y-type columns between outer tube, middle tube and inner tube may reduce a maximum displacement at the middle length of hollow shafts. Especially, the load-bearing column of X-type or Y-type hollow shaft is directly connected between outer tube and inner tube without a shift for reducing the vertical displacement. And increased thickness of a load-bearing column is recommended for reducing the vertical displacement and increasing the displacement behavior safety for an equivalent volume of a hollow shaft.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.282-287
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• 2008

Since glass-fiber reinforced composite decks have high-strength, light-weight and high durability, many researchs on the composite decks for bridges are currently performed and many composite decks are developed. In this paper, a composite deck with snap-fit connection for pedestrian bridge is developed and studied. A study on behavior of snap-fit connection of composite deck for pedestrian bridge during assembling or disassembling is performed by analysis and experiment.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.75-82
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• 1999

본 연구의 목적은 구체 경량화의 일환으로써, 복합재료(3-X Board, Al extrusion panel, etc) 사용에 대한 가능성을 판단하기 위한 기초자료를 구축하는데 있다. 해석 대상은 2층 기차의 객차부분이고, 구체에 적용하는 복합재료는 3-X Board를 이용하였다. 구체의 구조 건전성을 평가하기 위해 상용 유한요소 프로그램을 이용하여 다양한 하중 하에서의 응력해석을 수행하였다. 구체에 사용되는 복합재료(3-X board)의 응력발생 경향을 파악하는 것이 목적이므로, 상세한 모델보다는 단순화한 모델을 이용하였다. 응력집중은 센터실(center sill), 1층 바닥과 측면과의 연결부, 그리고, 구체의 앞부분 창문 모서리에서 발생하였다. 압축 및 수직하중 하에서의 응력값들은 재료의 항복강도 내에 존재하였으나, 고유진동수는 제한 값보다 낮은 값을 갖았다. 현재 상세 모델에 대한 해석을 수행 중에 있다. 본 연구는 복합재료(3-X board)가 적용된 구체에 대한 초기 연구로써 만족할 만한 결과를 제시한다.