선형 과도 동탄성문제 해석을 위한 유한요소방정식 Ⅱ

심우진 金烏工科大學校 産業技術開發硏究院 1999 産業技術開發硏究 Vol.15 No.-

In this paper, the advanced finite element formulation for the time domain analysis of transient elastodynamic problems is presented based on the Gurtin's variational principle which shows some good characteristics in numerical results owing to the transformation of the governing equations in differential type into that of integro-differential type with respect to the space and time variables. In the semidiscrete approximations of the field variables, and the space is approximated by the usual finite element discretization technique. Since the temporal approximation in each time interval is based on one order higher polynomial comparing to that of the author's previous paper[1], numerically more accurate results are expected.

선형 동적인 점탄성문제 해석을 위한 유한요소방정식

심우진 金烏工科大學校 1997 論文集 Vol.18 No.-

An efficient finite element formulation based on Gurtin's variational principle is presented for the linear transient dynamic viscoelastic analysis, which has some good characteristics to improve the numerical accuracy and stability in numerical implementations.

體積力을 지난 粘彈性 문제의 이론해

沈愚鎭 金烏工科大學校 1990 論文集 Vol.11 No.-

Now analytical solutions are presented for the advanced study of isotropic linear viscoelastic problems subjected to the gravitational and rotating body forces. In the derivation, the elastic-viscoelastic correspondence principle has been applied to the viscoelastic material which is elastic in dilatation and behaves like a standard linear solid in distorsion.

初等學校 校庭內 生態園 造成技法 : With a Special Reference to Hu-am Elementary School in Yong-san gu, Seoul 서울 龍山區 厚岩 初等學校 事例를 중심으로

진시현,심우경,이광우 韓國植物ㆍ人間ㆍ環境學會 2000 인간식물환경학회지 Vol.3 No.1

이 논문의 연구목적은 초등학교내에 생태원을 조성함으로써 아이들에게 자연과의 접촉기회를 제공하고자 실시한 바, 그 결과는 다음과 같다. 1. 초등학교 교과서에 나타나는 모든 동, 식물의 종류 초등학교의 교과서 분석 경과 274종의 식물종과 227종의 동물종이 나타났으며, 가장 높은 빈도수를 나타낸 곤충은 나비 78회, 잠자리 64회, 개미 51회, 벌 41회, 그리고 매미가 31회의 순으로 나타났다. 이는 교과서별 학년별로 빈도수를 조사한 결과와도 비슷한 양상을 나타낸 것이다. 초등학교 교과서 중 자연과 과목의 교육내용을 살펴본 결과, 1∼2학년 과정에서는 학교내의 뜰과 화단의 4계절 변화를 관찰하고 3∼6학년 과정에서는 생태계 전반에 걸친 세부적인 내용을 공부하도록 교육내용이 설정되었음을 알 수 있었다. 2. 용산구에 있는 15개의 초등학교의 옥외환경 조사 용산구에는 15개 학교가 있고, 그들의 옥외환경의 형태는 교재원과 생산원의 두 가지 종류로 나타났다. 대부분의 학교가 이 두 가지 형태로 나타났으나 남정, 보광, 원효로, 한강 초등학교는 생태원의 시설중 소동물 사육장 시설이 없었고, 교재원의 시설도 빈약하였다. 사례지역인 후암 초등학교는 도시의 중심부에 위치해 있는 다른 초등학교와는 달리 풍부한 생물상을 가지고 있는 남산에 인접하고 있기 때문에 생태원으로서의 기능성이 있는 것으로 보여진다. 3. 사례연구와 생태원 조성계획 생태원의 조성방법으로서 우선, 사례지인 후암 초등학교 부지의 현황조사를 하였고, 두 번째로 4가지 곤충(나비, 잠자리, 벌, 매미)들을 유치하기 위한 식물들을 선별하기 위해 이들이 식이식물로 조사된 식물들 중에서 교과서에 나오고 사례지역에 적합하며 내공해성을 가지며, 자생종이 식물들을 선별한 결과, 나비, 잠자리, 새를 유치하기 위한 식이식물로 각각 44, 17, 16종이 선별되었다. 또한 이 학교의 건물이 도로와 맞닿는 점을 감안하여 건물옥상에 생물서식지를 조성함으로서 남산으로부터의 풍부한 생물종의 유입을 유도하고, 더 나아가 학교 내에 조성되는 생태원으로 자연스럽게 유도하고자 하였다. 따라서 옥상 위의 생물서식공간은 수변공간계획과 식재계획을 통하여 곤충류와 조류뿐만 아니라 다양한 생물종이 서식되도록 하였고, 이를 통해 초등학교 학생들은 자연과의 친밀한 접촉기회를 가지게 될 것이다. The purpose of this study was to offer the opportunity of contact with the nature to urban children by the creation of the biotope in the elementary school ground. The results for this study were as follow: 1. The kinds of animals and plants the elementary school textbooks were 275 species and 227 animals. The frequencies of insect species in the elementary school textbook were the butterfly(75), dragonfly(64), ant(51), bee(41), and cicada(31) in order. These results were analogous to the numbers in each textbook and grade. In the 'Nature' textbook of the elementary school, there were educational contents to observe the ground and garden in 1, 2 grade courses and to study the detail of ecosystem in 3-6 grade course. 2. Inventory of the out-door environments of 15 elementary schools in Young-san Gu, Seoul. The number of total elementary school in Young-san Gu were fifteen, which had two garden types appeared as nature study and experimental farm. Two types of gardens were appeared mostly in all the elementary school but Nam-jung, Bu-kwang, Wonhyo-ro, Sin-swang, and Han-gang elementary school didn't have the experimental farms and also have the poor facilities of the nature study gardens. Huam elementary school had the possibility of the biotope creation because it was connected to Namsan park which posseses the abundant biota in contrast to the others in the center of the city. 3. Case study and biotope planning. To create the biotope, the site analysis was carred out and then plant species for inducing 4 kinds of insect (butterfly, dragonfly, bee, and cicada) were selected under the criteria as pollution-resistant, the school tree and flower, tolerance, and original habitat. Consequently, the numbers of plants for inducing butterflies, dragonflies and birds were 44, 17, 16 species separately. Also, it was planned to the induce abundant biota to building's roof as stepping stone from Namsan. These two biotopes were planned to be a habitat of various biota in addition of the water pond and the planting plan. Through the biotope created by this plan, the students of the elementary school will have more opportunity of contact with the nature.

3차원 탄성응력해석을 위한 유한요소 프로그램 KNUT3D의 개발

심우진,박인규,이기천 金烏工科大學校 1994 論文集 Vol.15 No.-

A basic and useful program KNUT3D is developed for the analysis of 3-dimensional elasticity and presented with a full explanation in a separate supplement for industrial researchers and graduate students. Linear and quadratic rectangular brick elements of the serendipity family are used in the finite element discretization of the elastic system to be solved. Through the numeral tests of several examples, the validity and adaptibility of KNUT3D are proved, so that it is expected that this work becomes to be a sound foundation for further extensions in the computational stress analysis.

時間領域에서의 線形 粘彈性問題 解析을 위한 有限要素解法의 公式化 Ⅰ

심우진 金烏工科大學校 1991 論文集 Vol.12 No.-

A general finite element formulation in integral type is presented for the time domain analysis of isotropic, linear viscoelastic problems. The semi-discrete variational approximation and elastic-viscoelastic correspondence principle play an important role in the theoretical extension of the present method. In the solution procedure of the final, linear algebraic system equations, only the repeated computations for the past history are required since the stiffness matrix is constant for a constant time increment. The stress computation algorithm in matrix form is given with detail explanations.

선형 과도 동탄성문제 해석을 위한 유한요소방정식 Ⅰ

심우진 金烏工科大學校 産業技術開發硏究院 1999 産業技術開發硏究 Vol.15 No.-

An efficient finite element formulation based of Gurtin's variational principle is presented for the time domain analysis of the linear transient elastodynamic problems, which formulation does not involve the time derivative terms, so that numerical accuracies may be improved much comparing to the conventional dynamic numerical algorithms, such as the Newmark method, which require the explicit relations among the acceleration, velocity, and displacement at each time node with the stable time stepping procedure for the time integration. Another good characteristic of this formulation is that unconditionally stable implicit time marching scheme is resulted so that if too much simplified assumptions are not made in the temporal approximation of adopted variables the stability problems do not occur.

온도 종속의 물성을 지닌 선형 열점탄성 문제해석을 위한 지배방정식

심우진 金烏工科大學校 1994 論文集 Vol.15 No.-

This paper provides full explanations about the governing equations for the analysis of quasi-static, uncoupled, homogeneous, isotropic and linear thermoviscoelastic problems under infinitesimal deformation and nonhomogeneous temperature field. The behavior of the viscoelastic solid is assumed to be thermo-rheologically simple, which is described by the temperature-time equivalence hypothesis and written in terms of the real and reduced times. At the end of paper(section 3) short comments for further work are also given.

홀과 노치를 지닌 2차원 평판에서의 응력집중감소에 관한 연구

심우진,최영필 金烏工科大學校 1996 論文集 Vol.17 No.-

Stress concentrations under uniaxial tension in 2-dimensional elastic plates due to geometric discontinuities such as holes and notches and their reductions by placing subsidiary holes and notches near stress raisers are studied by the method of photoelasticity. In general, photoelastic plates are very sensitive to heat so that test specimens should be carefully machined to prevent residual stresses Experimental details are given to reduce errors in measuring data by the reflection polariscope. Stress concentration factors of 12 useful specimen models are presented for the purpose of later comparative study with numerical results.

탄성-점탄성 상응원리를 이용한 선형 점탄성문제의 해석

沈愚鎭 金烏工科大學校 1986 論文集 Vol.7 No.-

The Elastic-Viscoelatic correspondence Principle ie Applied to Drive(1) the viscoelastic fundamental Solution which plays an impportant part in Boundary Element Method for viscoelastic analysis and(2) the displacement fields of a pressurized viscoelastic hollow cylinder in case of plane stress and plane strain and a pressurized circular hole within a viscoelastic infinite region. The material behavior is assumed tobe elastic under hydraulric pressure and like standard linear viscoelastkc material(or 3 element Voigt-type model) in shear.