• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.83-90
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on horizontally layered half-space considering the effects of the interior fluid and exterior soil medium in the frequency domain. the horizontal and rocking motions of the structures are included in this study. The fluid motion is expressed in terms of analytical velocity potential function which can be obtained by solving the boundary value problem including the sloshing behavior of the fluid as well as deformed configuration of the structure. The effect of the fluid is included in the equation of motion as the impulsive added mass and a frequency-dependent convective added mass along the nodes on the wetted boundary with structure. The soil medium is presented using the 3-D axisymmetric finite elements and dynamic infinite elements. The present method can be applied to the structures embedded in ground as well as on ground since it models the soil medium directly as well as the structure. For the purpose of vertification dynamci characteristics of a tank on homogeneous half-space is analyzed. Comparison of the present results with those by others shows good agreement.

• 한국해양공학회지
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• 제33권1호
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• pp.17-25
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• 2019

A numerical method is suggested for evaluating the singular integral of curved panels in the higher-order boundary element method. Two-step mapping procedures that are significantly related to the physical properties of singular behaviors were developed and illustrated. As a result, the singular behaviors were significantly alleviated, and the efficiency and robustness of the present method for tangentially and axially deformed elements were proven. However, inaccuracies and numerical instabilities of twisted elements were discovered as a result of nonlinearities.

• Advances in aircraft and spacecraft science
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• 제11권1호
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• pp.55-81
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• 2024

This paper presents the exact solutions and closed forms for of nonlinear stability and vibration behaviors of straight and curved beams with nonlinear viscoelastic boundary conditions, for the first time. The mathematical formulations of the beam are expressed based on Euler-Bernoulli beam theory with the von Karman nonlinearity to include the mid-plane stretching. The classical boundary conditions are replaced by nonlinear viscoelastic boundary conditions on both sides, that are presented by three elements (i.e., linear spring, nonlinear spring, and nonlinear damper). The nonlinear integro-differential equation of buckling problem subjected to nonlinear nonhomogeneous boundary conditions is derived and exactly solved to compute nonlinear static response and critical buckling load. The vibration problem is converted to nonlinear eigenvalue problem and solved analytically to calculate the natural frequencies and to predict the corresponding mode shapes. Parametric studies are carried out to depict the effects of nonlinear boundary conditions and amplitude of initial curvature on nonlinear static response and vibration behaviors of curved beam. Numerical results show that the nonlinear boundary conditions have significant effects on the critical buckling load, nonlinear buckling response and natural frequencies of the curved beam. The proposed model can be exploited in analysis of macrosystem (airfoil, flappers and wings) and microsystem (MEMS, nanosensor and nanoactuators).

• 전산구조공학
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• 제3권4호
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• pp.91-104
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• 1990

사각형 판 유한요소의 정적 성능을 여러 가지 문제에 대한 수치 실험을 통해 비교 분석하였다. Kirchhoff이론과 Mindlin이론에 근거한 변위요소, 평형요소, Mixed 또는 Hybrid요소들을 대상으로 문헌조사를 통해 우수요소를 선정하였으며 사각형 판 문제, 마름모형 판 문제, 원형 판 문제, 외팔보형 판 문제를 다양한 격자, 경계조건에 대해 풀어 해를 비교하였다. Kirchhoff요소에서는 12자유도요소로 Armanios의 요소, 24 자유도 요소로 Watkins요소의 거동이 우수하였으나 전반적으로 Mindlin요소에 비해 거동이 떨어진다. Mindlin요소 중에서는 Hinton의 요소가 효율성, 수렴성, 신뢰성의 면에서 가장 우수하나 마름모형 판 문제나 뒤틀린 격자 문제등에서는 거동이 좋지 않으므로 계속 연구할 필요가 있다.

• 소성∙가공
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• 제12권1호
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• pp.34-42
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• 2003

This paper presents a rigid-plastic finite element method to handle the frictional contact problem between two deformable bodies experiencing large deformation. The variational formulation combined with incremental quasi-static model is employed for treating the contact boundary condition. The frictional behavior of the model obeys Coulomb's law of friction. The proposed contact algorithms are classified into two categories, one for searching contacting nodes and the other for calculating contact forces at the contact surface. A slave node and master contact segment are defined using the geometric condition of finite elements on the contact interface. The penalty parameter is used to limit the penetration between contacting bodies, and the finite elements are coupled with contact boundary elements.us gates and cavity thicknesses. Through this study we have observed that the jetting is related to the die swell of material. This means that the jotting is strongly affected by the elastic flow property rather than the viscous flow property in viscoelastic characteristics of molten polymer. Different resins have different elastic properties, and elastic flow behavior depends on the shear rate of flow, i.e. injection speed. Large die swell would eliminate jetting however, the retardation of die swell would stimulate jetting. In the point of mole design, reducing the thickness ratio of cavity to gate can reduce or eliminate jetting regardless of amount of elasticity of polymer melt.

• KCI Concrete Journal
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• 제12권2호
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• pp.73-84
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• 2000

A new form of construction utilizing structural steel as the boundary elements in ductile flexural concrete walls is proposed to solve the bar congestion problems in such a heavily reinforced region, while maintaining the ductility and energy absorption capacity comparable to their traditional form. Two wall specimens containing rectangular hollow structural sections (HSS) and channels at their ends respectively, and one companion standard reinforced concrete wall specimen with concentrated end reinforcement were constructed and tested under reversed cyclic loading to evaluate the construction process as well as the structural performance. Initially, all three specimens were chosen and detailed with some caution to have approximately the same flexural capacity without change of the original shape and dimension of a rectangular cross section correction. Analysis and comparison of test results indicated that the reversed cyclic responses of three walls showed similar hysteretic properties, but in those with steel boundaries, local buckling of the corresponding steel webs and flanges following significant yielding was a dominant factor to determine the hysteretic response. The monotonic and cyclic responses predicted based on a sectional approach was also presented and found to be in good agreement with measured results. Design recommendations considering local instability of the structural steel elements and the interaction between steel chords and a concrete web member in such a composite wall are presented.

• 한국실내디자인학회논문집
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• 제22권5호
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• pp.293-301
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• 2013

The purpose of this study was to find the space perception by the scene and to analyze the characteristics in the exhibition space. The data for the analysis was collected through a questionnaire survey method. The questionnaire is composed of a scene selection on the panoramic photographs of the exhibition space. 'The 4 Rivers Cultural Center - The ARK' was selected as the subject of this survey. The results of the study are presented as follows : First, the space perception perceived imaged scenes rather than the specific elements of space. Second, the space perception was revealed through the 'Form', 'Materials', 'Light', 'Lighting', 'Furniture' and 'Media' of notable elements. Also that was perceived by forming 'Line', 'Surface' and 'Volume'. Particularly, the perception of 'Surface' was higher than 'Line' and 'Volume'. 'Surface' was perceived mostly through the 'Color'. The perception of 'Line' was positive to 'Boundary' or 'Continuous placement of the light'. In addition, the perception of 'Volume' was positive to 'The curve of the form', 'Transparent material', 'Three-dimensional elements'. Finally, The type of space perception was chosen as 'Extension', 'Center', 'Deep', 'Boundary' and 'Formative'. In this way, the results of this study will set a foundation for developing design methods to induce the space perception by the scene in the exhibition space.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.239-240
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• 2012

• 한국주거학회논문집
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• 제22권1호
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• pp.57-64
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• 2011

The purpose of this study is to investigate design elements to strengthen apartment communities in territoriality perspectives. To this end, the study first identified the functions of territoriality to communities, and examined precedent studies on community planning. Then, looking into actual apartment, the study analyzed design elements of the apartments by territoriality functions, and found significant community-building and community-strengthening elements. The results of case studies are as follows: Specific design elements are 1) both individual and shared places from the perspective of possession, 2) both physical boundaries including visible mark and physical demarcation, and emotional boundaries including space arrangement and visual expansion from the perspective of boundary-regulation, 3) both physical proximity, such as providing space for physical encounter and easy access, and emotional proximity such as homogeneity and intimacy from the perspective of proximity 4) design differentiation and adoption of the design concept to express the identity of the community from the perspective of proximity personalization.

• 한국디지털건축인테리어학회논문집
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• 제9권3호
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• pp.47-57
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• 2009

The purpose of this study is to propose the design elements useful to give place identity to street space. The theory for place identity is studied and the components-Physical element, Sense, Program, Activity, Context-for identity of place is created. In the case study of SamcheongdongGil, the qualitative research method of Free Picturing Technique and Cognitive Mapping is executed and the samples gathered from the research are analyzed. In the process of analysis, the contents of qualitative evaluation by users is put in order as components for identity of place. Moreover, the design elements for street space are extracted from the case study and theories of urban design. The design elements are summarized as the followings: street pattern with high permeability, various streetscapes, greenscapes, semi public(private) spaces, the third places, public arts, transparent facades, and outdoor activities. Finally, the fruits and boundary of this study are described and the importance of place identity is.