• 한국강구조학회 논문집
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• 제18권6호
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• pp.687-696
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• 2006

본 논문에서는 공간 뼈대구조의 탄-소성 후좌굴 강도를 파악하기 위한 효율적인 수치해석 기법을 개발하고, 매개변수해석을 통하여 보-기둥 및 뼈대구조물의 비탄성 후좌굴 거동을 분석하였다. 외력의 증가에 따라 점진적인 강도감소효과를 효율적으로 고려하는 개선된 소성힌지 해석법을 적용하여 문헌에서 제시된 다양한 잔류응력 분포 형태에 따른 뼈대구조물의 탄-소성 해석을 수행하였다. 요소의 소성화 진행정도를 나타내는 파라미터들을 도입하고 등가단면력 및 요소분할에 따른 매개변수해석을 수행하여 그 결과를 문헌에서 제시된 소성영역해석, 쉘요소를 이용한 정밀해석 그리고 실험결과와 비교하여 뼈대구조물 극한강도를 평가하였다.

• 산업기술연구
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• 제18권
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• pp.131-138
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• 1998

Numerical modeling for electromagnetic exploration methods are essential to understand behaviours of electromagnetic fields in complex subsurfaces. In this study, a finite element method was adopted as a numerical scheme for the 2.5-dimensional forward problem. And a finite element equation considering linear conductivity variation was proposed when 2.5-dimensional differential equation to couple eletric and magnetic field was implemented. Model parameters were investigated for near-field with large source effects and far-field with responses dominantly by homogeneous half-space. Numerical responses by this study were compared with analytic solutions in homogeneous half-space and compared with other three dimensional numerical results.

• Earthquakes and Structures
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• 제26권2호
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• pp.163-174
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• 2024

Dynamic equilibrium equations for finite element analysis were derived for the free field one-dimensional shear wave propagation through the horizontally layered soil deposits with the elastic half-space. We expressed Rayleigh's viscous damping consisting of mass and stiffness proportional terms. We considered two cases where damping matrices are defined in the total and relative displacement fields. Two forms of equilibrium equations are presented; one in terms of total motions and the other in terms of relative motions. To evaluate the performance of new equilibrium equations, we conducted two sets of site response analyses and directly compared them with the exact closed-form frequency domain solution. Results show that the base shear force as earthquake load represents the simpler form of equilibrium equation to be used for the finite element method. Conventional finite element procedure using base acceleration as earthquake load predicts exact solution reasonably well even in soil deposits with unrealistically high damping.

• 한국실내디자인학회논문집
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• 제19권3호
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• pp.86-94
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• 2010

Art-Wall is the term for a surface wall representing artistic expression by using different materials or images in interior spaces. Usually this is the focal point in an interior space and sometimes it called as an image wall. In the new millenium Art-walls began to use in living spaces. While in the early stages of the development, Art-Wall was limited in a living room, in contemporary it spread into overall living spaces using various patterns and materials. Therefore, the research on Art-Walls in contemporary living spaces is essential to understand this development. The purpose of this study is to find out characteristics of patterns on Art-Walls as an imagery element in contemporary interior spaces. To analyze the characteristic, the analysis table for Art-Walls are constructed based on classifications of wallpapers and textiles. Based on this analysis table, 89 examples of Art-Walls from four major periodicals from 2008 to 2009 were examined. As a result of the analysis, in contemporary interior spaces solid-texture pattern is most frequently appeared. Then natural motifs are the next most popular using oversized or irregular layouts. The result shows that naturalistic expression is significant in interior space in 2008 to 2009. Therefore, Art-Walls that adapted diverse patterns are an essential element in contemporary interiors to represent the major concept of the space.

• 전기학회논문지
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• 제58권10호
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• pp.2011-2015
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• 2009

In an insulating dielectric liquid such as transformer oil, space charge injection and propagation were analyzed under the Fowler-Nordheim and Richardson-Dushman's thermal emission charge injection conditions for blade-plane electrodes stressed by a step voltage. The governing equations were composed of all five equations such as the Poisson's equation for electric fields, three continuity equations for electrons, negative, and positive ions, and energy balanced equation for temperature distributions. The governing equations for each carrier, the continuity equations, belong to the hyperbolic-type PDE of which the solution has a step change at the space charge front resulting in numerical instabilities. To decrease these instabilities, the governing equations were solved simultaneously by the Finite Element Method (FEM) employing the artificial diffusion scheme as a stabilization technique. Additionally, the terminal current was calculated by using the generalized energy method which is based on the Poynting's theorem, and represents more reliable and stable approach for evaluating discharge current. To verify the proposed method, the discharge phenomena were successfully applied to the blade~plane electrodes, where the radius of blade cap was $50{\mu}m$.

• 한국실내디자인학회논문집
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• 제16권3호
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• pp.38-45
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• 2007

In the architectural space of modem age, expanding to the vertical and horizontal direction for the interaction between space and space is becoming an indispensable factor, and in this expansion, ramps are being positioned as one of the important factors. With an increased use of ramps, they show a variety of changes in types, functions and even concepts. The space where modem ramps are used exhibits a phenomenon that accommodates and expands many functions as well as the confined function of moving people, and is widening the scope of recognition on the functions of ramp. In addition, this phenomenon can be seen as an architectural reflection on the complexation trend of the modem society, the components comprising a ramp contact the body of experiencers closely and thus have a direct effect on their behavior or feeling, and owing to this, it is a space where new functions and meaning are highly likely to be derived. In this study, spaces where ramps are used stay away from an element of uniform vertical movement but have an independent environment within the entire space, thereby being used as a space dominating the nature of the building, not a subsidiary element of it. In this study, therefore, it could be known that spaces in which ramps are used are different in their meaning according to the patterns, not as an element of uniform vertical movement. In addition, these conclusions are the results by analyzing the patterns of ramps taking place in modem spaces and are thought to be helpful in understanding spaces where ramps are used.

• 충청수학회지
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• 제6권1호
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• pp.59-64
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• 1993

In this note, we shall give a maximal element existence theorem for condensing multimaps in a locally convex Hausdorff topological vector space.

• 한국항공우주학회지
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• 제33권2호
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• pp.46-53
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• 2005

곡면 사각형 쉘 요소들이 다수인 것에 비해, 곡면 삼각형 요소들은 아주 소수이다. 이미 발표된, 선형 해석을 위한 6절점 2차 쉘 요소의 가정 자연 변형도 이론에 기초해, 본 연구에서는 6절점 쉘 요소의 기하학적 비선형 해석을 수행하였다. 쉘 요소는 표준 절점 자유도만으로 곡면 모델링이 가능하고, 수치해석 결과가 보여주는 바와 같이 다양한 잠김 현상들을 제거하는데 효율적인 요소임을 확인하였다.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.56-63
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• 2007

In case of bus rollover, the body structure of the bus should be designed to ensure the survival space for passengers. So, this study focuses on evaluating rollover strength through a computer simulation using the commercial code, LS-DYNA3D at the initial stage of vehicle development. For this study, section structure was modeled using a simple beam element, and impact boundary conditions required by ECE(Economic Commission for Europe) regulation No.66 were applied. In order to confirm the validity of the beam element bus model, the results compared with the test results and shell element bus model. The analysis errors from beam element bus model are due to the difference in strain energy of joint area between beam and shell model. In this study, a method for the joint modeling was suggested by using nonlinear springs to which the collapse mechanisms were applied.

• 한국항공우주학회지
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• 제46권11호
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• pp.892-901
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• 2018

본 연구에서는 극초음속 비행체의 공력/열/탄성학적 거동을 반영할 수 있는 효율적인 공력 열하중 요소를 개발하였다. 빈번하게 설계 변경이 이루어지는 초기 설계 단계에서 효율적으로 사용될 수 있도록 준 해석적인 관계식을 적용하여 공력 하중과 열 하중을 구조 변형의 함수로 기술하고, 이를 기반으로 공력 열하중 요소를 정식화하였다. 정식화된 요소는 상용 프로그램의 사용자 서브루틴 형태로 구현하였으며, 이를 이용하여 극초음속 비행체 조종면의 공력/열/탄성학적 유한요소 연계해석을 수행하고 그 유용성을 확인하였다.