서지주요정보
무한지반에서의 다양한 거동감쇠특성을 해석할 수 있는 p-버전 무한요소의 개발 = Development of p-version infinite elements for analyzing various decay characteristics in unbounded soils
서명 / 저자 무한지반에서의 다양한 거동감쇠특성을 해석할 수 있는 p-버전 무한요소의 개발 = Development of p-version infinite elements for analyzing various decay characteristics in unbounded soils / 고광훈.
저자명 고광훈 ; Koh, Kwang-Hoon
발행사항 [대전 : 한국과학기술원, 1998].
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8009261

소장위치/청구기호

학술문화관(문화관) 보존서고

DCE 98012

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초록정보

Engineering problems involving unbounded domains are encountered in many areas, such as soil-structure interaction, consolidation of soils, and underground structures. The unbounded problems can be effectively and accurately analyzed by using appropriate infinite elements. Because the concept of infinite elements is the same as that of finite elements except for the infinity of the element domain, the infinite elements can be readily implemented in an usual finite element method. Thus, in the infinite element method, the near-field region is modeled by conventional finite elements, while the far-field region is represented by infinite elements. There exist many geotechnical problems where the unknown variables decay with respect to $1/r^n$(n=0.5,1,2,…). Each type of decay characteristics was previously modeled by using each infinite element in which only one type of decay characteristics could be represented. Such an infinite element could be formulated only if analytical solutions or the decay characteristics of variables were known. And accurate results could be obtained only if the selected infinite elements for the analysis were appropriate for the decay characteristics of the problem. Therefore, it has been necessary to develop an infinite element to represent various types of decay characteristics in unbounded media. This dissertation presents p-version infinite elements for analyzing $1/r^n$ type of decay problems in an unbounded soil. In order to model exterior unbounded regions, two kinds of infinite elements were developed. They are horizontal and radial infinite elements. Orthogonal polynomial series of Laguerre polynomials multiplied by an exponential decay function were proposed for representing $1/r^n$ type decay functions. The proposed polynomials were validated by checking the orthogonality of the polynomials, the regular condition and the accuracy of approximation. The shape functions of the p-version infinite elements were derived by using the orthogonal polynomial series. To verify the proposed p-version infinite elements, some numerical example analyses were carried out : a rigid strip footing and a flexible disk footing on a homogeneous half-space soil or on an unbounded layered soil which is horizontally infinite ; a circular tunnel and a square tunnel excavated in a homogeneous infinite soil or in an unbounded layered soil with initial earth stress fields. Compared with the analytical solutions and the numerical solutions obtained by a finite element method, it has been found that the proposed p-version infinite element method offers accurate solutions. Infinite element analysis by increasing the polynomial order of a p-version infinite element, gives very similar results to those obtained from the finite element analysis by increasing the domain size. And the results of the infinite element analysis converged to exact solutions. Therefore it seems that the proposed infinite element could efficiently represent the decay characteristics of the displacement in unbounded soils. Making use of the proposed p-version infinite elements, the total number of elements and the degrees of freedom for analysis could be significantly reduced. Unsteady state seepage analyses were also carried out for a semi-infinite soil with various boundary conditions. Comparison of the results with those of analytical solutions and other methods showed that the present method also offers good solutions in this type of problems. Using the proposed infinite elements, the unbounded domain problems with various decay characteristics can be efficiently analyzed.

서지기타정보

서지기타정보
청구기호 {DCE 98012
형태사항 viii, 117 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 : A, Error 함수 및 관련함수들. - B, Laguerre 다항식. - C, 비정상 침투류의 유한요소 수식화
저자명의 영문표기 : Kwang-Hoon Koh
지도교수의 한글표기 : 이승래
지도교수의 영문표기 : Seung-Rae Lee
수록잡지명 : "p-Version Static Infinite Element for Representing $1/r^{n}$ Type Decay Problems in Unbounded Media". Computers and Geotechnics. Elsevier Science Ltd., vol.22, no.1, pp. 73-89 (1998)
학위논문 학위논문(박사) - 한국과학기술원 : 토목공학과,
서지주기 참고문헌 : p. 106-112
주제 무한지반
p-버전 기법
무한요소해석
Unbounded soils
p-version method
Infinite element analysis
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