• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.117-125
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• 1997

상계요소 해석(UBET) 프로그램은 비대칭 단조공정에서의 다이 충만과정과 단조 하중등을 예측하기 위하여 개발되었다. 보다 용이하게 단조 공정을 해석하기 위하여 비대칭 형상의 단조공정을 평면변형부(길이 부분)과 축대칭변형부(라운딩 부분)으로 나누었다. 평면변형부와 축대칭 변형부의 경계는 전단에너지를 고려하여 결합하는 빌딩 블록 방법(building block method)을 이용하였다. 그리고 본 연구의 비대칭 형상을 단조하는데 최적의 초기시편 형상으로 아령형의 시편(dumbbell-typed billet)을 제시하였다. 또한 실험은 상온에서 플라스티신을 사용하여 수행되었고 수치해석 결과와 실험결과는 비교적 잘 일치하였다.상계요소 해석(UBET) 프로그램은 비대칭 단조공정에서의 다이 충만과정과 단조 하중등을 예측하기 위하여 개발되었다. 보다 용이하게 단조 공정을 해석하기 위하여 비대칭 형상의 단조공정을 평면변형부(길이 부분)과 축대칭변형부(라운딩 부분)으로 나누었다. 평면변형부와 축대칭 변형부의 경계는 전단에너지를 고려하여 결합하는 빌딩 블록 방법(building block method)을 이용하였다. 그리고 본 연구의 비대칭 형상을 단조하는데 최적의 초기시편 형상으로 아령형의 시편(dumbbell-typed billet)을 제시하였다. 또한 실험은 상온에서 플라스티신을 사용하여 수행되었고 수치해석 결과와 실험결과는 비교적 잘 일치하였다.

• 한국HCI학회:학술대회논문집
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• 2008.02c
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• pp.19-24
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• 2008

This paper presents a physically-based haptic rendering algorithm for a deformable object based on visual information about the intervention between a tool and a real object in a remote place. The physically-based model of a deformable object is created from the mechanical properties of the object and the captured image obtained with a CCD camera. When a slave system exerts manipulation tasks on a deformable object, the reaction force for haptic rendering is computed using boundary element method. Snakes algorithm is used to obtain the geometry information of a deformable object. The proposed haptic rendering algorithm can provide haptic feedback to a user without using a force transducer in a teleoperation system.

• Journal of the Korea Concrete Institute
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• v.14 no.5
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• pp.766-773
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• 2002

The failure phenomenon of overlaid concrete structures, such as surface crack, and peel-off failure, shear bond failure in the end contact zone, was investigated due to humidity changes. To investigate this failure phenomenon, the surface tensile stress, and the shear stress, the vertical tensile stress in the contact zone were analysed using the non-linear stress-strain relationship of material such as strain-hardening- and strain-softening diagrams. Overlay thickness and overlay material were the main variables in the analyses. It is assumed that the initial surface humidity of overlaid concrete structures was 100％ r.H. With a atmospheric humidity of 55％ r.H. and two load cases for drying(LCI), curing and drying(LC2), the stress states of overlaid concrete structures were calculated. The result shows that only fictitious cracks occurred in the overlay surface of CM2O, ECM25, and no shear bond failure occurred in the contact zone without CM2O. The peel-off failure was proved to be the main cause of the damage in the overlaid concrete structures. Only for overlay thickness of 1cm occurred no peel-off failure in the case of drying after a long-term public use(LC1). In the case of curing and drying during overlay work(LC2) occurred the peel-off failure within 1.5days for all the overlaid concrete structures.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.171-181
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• 2013

The radial mapping rule in bounding surface model was experimentally investigated by analyzing the drained stress probe tests on Chicago clays. The experimental data obtained from 10 drained stress probe paths were analyzed to calculate the directions of the plastic strain increments. The anisotropic bounding surface model was adopted to represent a bounding yield surface which resides in the pre-consolidation yield stress of undisturbed clays. The projection origins were estimated by finding the interceptions of the straight lines passing through the current stress point and the imaginary yield stress point on the bounding surface. The results show that the projection origin is not fixed at a point but moves toward the direction of the stress probe path after it is established around the initial stress point.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.25-30
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• 2001

The stress intensity factors for edge cracks located at the bonding interface between the semiconductor chip and the adhesive layer subjected to a uniform transverse tensile strain are investigated. Such cracks might be generated due to a stress singularity in the vicinity of the free surface. The boundary element method (BEM) is employed to investigate the behavior of interface stresses. The amplitude of complex stress intensity factor depends on the crack length, but it has a constant value at large crack lengths. The rapid propagation of interface crack is expected if the transverse tensile strain reaches a critical value.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.643-644
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• 2021

최근 가상 디지털미디어에 대한 관심이 집중되고 있는 시대적 상황에서 물의 다양한 속성에 관한 시공간적 표현은 동시대 매체 미술에서 중요한 의미를 지닌다. 본 연구는 물의 표면을 경계(boundary)로 그 경계면의 상하 공간, 경계면과의 거리감, 물그림자, 물의 투영성 등을 통한 시공간 표현에 관한 것이다. 대상 작품으로는 빌 비올라의 을 중심으로, 레안드로 에를리치의 설치 작품, 데이비드 호크니의 회화를 사례로 제시한다. 다양한 미술 매체를 통해 변형된 시공간성은 물 표면이라는 매개체와의 관계적 특성 안에서 이미지의 환상성을 부각한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.664-671
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• 2017

This paper presents a numerical analysis of behaviors of rear closer of vertical launch system under rocket plume based on fluid structure interaction analysis. The rocket plume loading is modeled by fully Eulerian method and elasto-plastic behavior of rear cover is calculated by total Lagrangian method based on a 9-node planar element. The interface motion and boundary conditions are described by a hybrid particle level-set method within the ghost fluid framework. We compare the fluid flow pattern between different rear closer models which are elast-plastic and rigid deformation.

• Tunnel and Underground Space
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• v.8 no.3
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• pp.249-256
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• 1998

Pocheon, Keochang and Sangju granite samples of different granularity and mineralogical composition were thermally treated at pre-determined temperature of $600^{\circ}C$. Thermally-induced microcracks were characterized using an optical microscopy and their effects on the deformation behavior of thermally cycled samples were studied performing compressive mechanical tests. Optical observations shows that by $600^{\circ}C$ nearlly all crystal boundaries open and the new intracrystalline cracks form in the more grains. The intracrystalline cracks are most pronounced at thermally treated Pocheon and Keochang granite samples. Results from mechanical tests represents negative lateral strains, which give negative Poisson's ratios. It is the most probable that negative lateral strains are produced by residual stresses induced during cooling.

• Journal of Welding and Joining
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• v.17 no.1
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• pp.104-115
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• 1999

There have been many studies on the two dimensional thermo-elasto-plastic analysis in welding process, mostly from viewpoint of residual stresses. In this study, the temperature distribution, transient thermal stress, and angular distortion during bead-on-plate gas metal arc welding of rectangular plates were analyzed by using the finite element method. A nonlinear heat transfer analysis was first performed by taking account of the temperature-dependent material properties and convection heat losses on the surface. This was followed by a thermo-elasto-plastic stresses and distortion analysis that incorporates the constrained boundary condition of the two dimensional solution domain to get the three dimensional size effect of the plate. The constrained boundary conditions adopted in this study were the constant displacement condition over the whole two dimensional section for axial movement in the welding direction, and the force boundary condition for rotational movementof the domain around the axis of the welding direction. It could be revealed that the theoretical predictions of the angular distortion have an improved agreement with the experimentally obtained data presented in the previous study.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.669-675
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• 2020

In this study, 3D analysis was compared in evaluating the track deformation of subway structures during adjacent excavation. For the 3D analysis model, the boundary conditions of the tunnel model and the application level of the ground water were analyzed as variables. As the result of the effects of track irregularity using the 3D model, the analysis model considering the site ground water level instead of the design values and changing the constraint of the boundary condition is more reasonable. In addition, the influence of track irregularity due to the boundary condition and load condition of the analytical model is more obvious in the factors directly affected by the longitudinal relative displacement of the rail, such as alignment, cross level and gauge irregularity. Therefore, the evaluation on track stability according to adjacent excavation work was appropriate to analysed the longitudinal deformation of the track by using 3D model that could be investigate the deformation of rail. In addition, the boundary condition and load condition(ground water level) of the numerical model was important for accurate analysis results.