• 대한조선학회논문집
• /
• 제44권2호
• /
• pp.130-138
• /
• 2007

A coupled variational equation for fluid-structure interaction (FSI) problems is derived from a steady state Navier-Stokes equation for incompressible Newtonian fluid and an equilibrium equation for geometrically nonlinear structures. For a fully coupled FSI formulation, between fluid and structures, a traction continuity condition is considered at interfaces where a no-slip condition is imposed. Under total Lagrange formulation in the structural domain, finite rotations are well described by using the second Piola-Kirchhoff stress and Green-Lagrange strain tensors. An adjoint shape design sensitivity analysis (DSA) method based on material derivative approach is applied to the FSI problem to develop a shape design optimization method. Demonstrating some numerical examples, the accuracy and efficiency of the developed DSA method is verified in comparison with finite difference sensitivity. Also, for the FSI problems, a shape design optimization is performed to obtain a maximal stiffness structure satisfying an allowable volume constraint.

• 한국공간구조학회:학술대회논문집
• /
• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
• /
• pp.155-158
• /
• 2008

대공간구조물의 스팬이 장스팬이 됨에 따라서 고유진동수가 저진동수 영역으로 감에 따라서 강풍에 대한 동적응답의 증가하고 있다. 그러나 기본계획설계 단계에서 국내 공간구조물에 대한 고유진동수의 스팬에 대한 식이 제안되어 있지 않은 관계로 경제적인 구조시스템을 수립하는데 많은 애로 사항이 있다. 따라서 이 논문은 국내에 이미 시공된 대공간건축물 중 월드컵경기장 위주로 각 건축물의 스팬에 대한 고유진동수에 관한 논문이다. 수집된 고유진동수에 대한 자료는 하나의 계측치와 6개의 고유치해석 결과에 기초하고 있다. 고유진동수의 스팬에 대한 식을 일본의 계측치와 비교하였고, 약산식을 제안하여 기본설계의 기초자료로 제공하고자 한다.

• Wind and Structures
• /
• 제19권1호
• /
• pp.35-58
• /
• 2014

A numerical simultaneous solution involving a linear elastic model was applied to study the fluid-structure interaction (FSI) of membrane structures under wind actions, i.e., formulating the fluid-structure system with a single equation system and solving it simultaneously. The linear elastic model was applied to managing the data transfer at the fluid and structure interface. The monolithic equation of the FSI system was formulated by means of variational forms of equations for the fluid, structure and linear elastic model, and was solved by the Newton-Raphson method. Computation procedures of the proposed simultaneous solution are presented. It was applied to computation of flow around an elastic cylinder and a typical FSI problem to verify the validity and accuracy of the method. Then fluid-structure interaction analyses of a saddle membrane structure under wind actions for three typical cases were performed with the method. Wind pressure, wind-induced responses, displacement power spectra, aerodynamic damping and added mass of the membrane structure were computed and analyzed.

• 한국지반공학회논문집
• /
• 제36권12호
• /
• pp.27-34
• /
• 2020

구조물에 대한 축대칭 쉘요소는 지반과 구조물의 상호작용에 대한 유한요소해석에서 효율성과 정확성을 높이게 된다. 본 논문에서는 Kirchhoff 이론에 근거한 축대칭 쉘요소의 힘평형 방정식과 모멘트 평형 방정식을 유도하였다. 축방향 변형에 대한 지배방정식은 등매개변수 형상함수를 이용한 Galerkin 수식화를 수행하고, 휨에 대한 지배방정식은 고차의 형상함수를 이용하였다. 개발된 축대칭 쉘요소는 지반과의 연계해석을 위하여 지반해석 유한요소 프로그램인 Geo-COUS에 결합하였다. 원형판과 액체 저장 탱크에 대한 예제해석을 통하여 개발된 요소의 정확성을 확인하였다. 그리고 축대칭 쉘요소에 대한 에너지 평형방정식을 제시하였다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
• /
• 제12권5호
• /
• pp.157-164
• /
• 2023

자바의 최신 기능인 함수 인터페이스와 람다식에 대한 의미구조를 명세하는 것은 향후 유사한 기능을 설계할 때 참고할 수 있고 표준화하는 과정이나 최적화된 번역기를 구현하는 과정에서도 필요하다. 본 연구에서는 자바의 함수 인터페이스와 람다식에 대한 의미구조를 표현하기 위해 기존의 작용식을 수정하고 업그레이드해서 함수 인터페이스와 람다식의 정적·동적 의미구조를 표현하는 작용식 3.0을 새롭게 제시한다. 작용식 3.0에 명세된 의미구조를 자바로 구현해 자바 프로그램들에 대한 실행시간을 측정하고 시뮬레이션을 통해 작용식 3.0이 구현가능한 실제적인 의미구조 명세법인 것을 입증한다. 판독성(Readability) 측면, 모듈성(Modularity) 측면, 확장성(Extensibility) 측면, 융통성(Flexibility) 측면에서 대표적인 의미구조 표현법과 작용식 3.0을 비교하여 작용식 3.0의 우월성을 확인하고자 한다.

• Journal of the Korean Data and Information Science Society
• /
• 제15권2호
• /
• pp.395-403
• /
• 2004

The purpose of this study is to investigate the structure relationships between job satisfaction of dental residents and its related factors. The study subject was 458 dental residents who were training at 6 university dental hospitals in Korea. Data for this study were obtained by self-administrated questionnaire during 3 months. Structure equation modeling using LISREL procedure was statistically appropriate and well fitted. By the model, the socio-demographic characteristics, working condition, and status perception directly influenced on subscale satisfactions, and the subscale satisfactions positively influenced on job satisfaction.

• Wind and Structures
• /
• 제3권4호
• /
• pp.291-302
• /
• 2000

A new finite element technique to solve the problem of wind and structure interactions is presented. Conventionally, wind analysis is performed on the Eulerian description in which the finite element mesh would not move in accordance with the wind flow. However, it is not the case in wind-structure interaction problems because nodes attached to the surface of structure should move with the displacement of structure. The arbitrary Lagrangian-Eulerian (ALE) method treats the mesh and flow independently, and allow the mesh to move. In this study, the analysis domain is divided into regions of the structure, air around the structure and the interface of two regions. To satisfy the compatibility and equilibrium conditions between separated regions and to carry out the efficient analysis, the rigid link is used. Also the equation of wind and that of structure are arranged in a single matrix equation.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
• /
• pp.226-233
• /
• 1999

When we numerically model the bridge under seismic condition, the full model combining the super-structure and the sub-structure is considered for the more accurate results than the separate model. In this case, the super-structure is connected with the sub-structure by the elastic pad shoe that is difficult to model, because it has the three translational elastic stiffness and the three rotational elastic stiffness. The two-node General Link element is derived in finite element equation representing such a pad shoe, and it is verified by comparing the one General Link element model with the corresponding three legacy spring element model. It is easy to model the pad shoe, if the General Link finite element is used. And the seismic analysis result of the bridge full model structure, which is modeled with the General Link element, has been compared with the one of the separate model structure. The present study gives. more conservative result than that of the separate model, which does not consider the dynamic behaviour of the sub-structure.

• 한국수학교육학회지시리즈D:수학교육연구
• /
• 제14권1호
• /
• pp.33-50
• /
• 2010

The mathematical thinking which transforms important mathematical content and developed into mathematical structure is a vital process in building up mathematical ability as mathematical knowledge based on structure. Such process based on students' recognition of mathematical concept. Developing mathematical thinking into mathematical structure happens when different cognitive units are connected and compressed to form schema of solution, which could happen through some guided problems. The effort of arithmetic approach in problem solving did not necessarily provide students the structure schema of solution. The using of equation to solve the problem is based on the schema of building equation, and is not necessary recognizing the structure of the solution, as the recognition of structure may be lost in the process of simplification of algebraic expressions, leaving only the final numeric answer of the problem.

• 한국해양공학회지
• /
• 제5권1호
• /
• pp.55-63
• /
• 1991

This study is to predict accurately the wave induced current accuring by the radiation stress which acts as the driving force around Nearshore structure. For the wave induced current, the depth integrated and time averaged governing equation of an unsteady nonlinear form is derived from the continuity and momentum equation of an incompressible fluid. Numerical solutions are obtained by a finite difference method for the governing equation. In the vicinity of a structure, computed flow patterns show good agreement with the hydraulic experimental data. The numerical results obtained by neglecting the convective term show a large change of alongshore and offshore current.