• 한국해안해양공학회지
• /
• 제1권1호
• /
• pp.93-101
• /
• 1989

본 논문에서는 가이드 타워, 텐션 레그 프랫폼, 무어링 부이, 해저 케이블, 사장교, 현수교, 케이블 루프 등과 같은 해상 및 육상 구조물의 유한요소 모델에 사용하기 위한 기하학적 비선형 케이블 요소를 연구 제시하였으며, 케이블 요소는 평면내에서 임의의 하중과 기하형상을 갖는 케이블에 대한 탄성현수 케이블 이론으로부터의 적합방정식과 연성행렬을 직접 이용하여 유도하였다. 또한, 유도된 케이블 유한요소에 근거하여, 케이블 부재를 사용하는 구조물들의 유한요소 해석을 위해 전산 프로그램을 개발하였으며, 시간영역 동적 해석을 위해 뉴마크-베타의 직접적분법을 사용하였고, 각 시간간격에서의 비선형 평형방정식 및 적합방정식을 풀기 위한 방법으로서 뉴톤-랩슨의 반복법을 사용하였다. 이상과 같이 개발된 전산 프로그램을 이용하여 케이블 부재에 대한 정적 및 동적 해석을 수행한 후 그 결과를 분석ㆍ고찰하여 보았다.

• 한국압력기기공학회 논문집
• /
• 제17권1호
• /
• pp.36-48
• /
• 2021

As the material aging of nuclear power plants has been progressing in domestic and overseas, crack growth becomes one of the most important issues. In this respect, the crack growth assessment has been considered an essential part of structural integrity. The crack growth assessment for nuclear power plants has been generally performed based on ASME B&PV Code, Sec. XI but the idealization of crack shape and the conservative solutions of stress intensity factor (SIF) are used. Although finite element analysis (FEA) based on iterative crack growth analysis is considered as an alternative method to simulate crack growth, there are yet no guidelines to model the crack-tip spider-web mesh for such analysis. In this study, effects of various meshing factors on FE SIF calculation are systematically examined. Based on FEA results, proper criteria for spider-web mesh in crack-tip are suggested. The validation of SIF calculation method through mapping initial stress field is investigated to consider initial residual stress on crack growth. The iterative crack-tip modeling program to simulate crack growth is developed using the proposed criteria for spider-web mesh design. The SIF results from the developed program are validated by comparing with those from technical reports of other institutes.

• 한국구조물진단유지관리공학회 논문집
• /
• 제12권4호
• /
• pp.133-140
• /
• 2008

콘크리트 구조물에 대한 설계법이 현재의 한계상태 설계법에서 성능기반 설계법으로 전환되고 있는 추세이며, 이에 대한 연구가 미국, 유럽 및 일본 등에서 이루어지고 있다. 성능기반 설계법은 현행의 설계규준에서의 많은 불확실성(uncertainty)을 합리적으로 고려함으로서, 구조물이 일정한 신뢰성과 안전성을 확보하도록 하기 위한 연구로서, 신뢰도 높은 비선형 해석기술의 확보와 함께 이를 직접 설계에 적용하기 위한 방안에 대한 연구가 필요하다. 이 연구에서는 저자 등에 의하여 개발된 비선형 유한요소 해석 프로그램(RCAHEST)을 신뢰성 있는 철근콘크리트 기둥 실험체 적용하여 그 적용성과 타당성을 검증하였고, 신뢰성 이론을 바탕으로 파괴에 대한 목표 신뢰지수를 확보할 수 있도록 하는, 비선형 유한요소해석으로부터의 해석결과에 적용할 안전계수를 산정하여 현행의 설계 기준등과의 비교 분석을 수행하였다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
• /
• pp.855-860
• /
• 2002

This paper is about seismic performance of the StLRB(S.T.U＋PETE＋LRB) system, that is among various base isolator. A rational modeling of StLRB system has been presented that used Nllink element. We get theoretical solutions of equation of motion of the system and compared with numerical solutions using a finite element program, Thus, a verified modeling can be applied bridge structure of multi-degree-of-fredoom systems.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1993년도 가을 학술발표회논문집
• /
• pp.106-112
• /
• 1993

This paper presents the optimum design of reinforced concrete conical shell which is fixed at the base and free at the top. The calculation of stresses is done using the SMAP(Segmented Matrix Analysis Package)program which uses the simple finite element method of analysis. The objective function contains the ratios of the unit cost of reinforcements and formwork to that of concrete. To Simplify the optimization procedure, the final optimum design of conical shell is obtained by combining the result of each element. The results are presented and discussed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1963-1967
• /
• 1996

This paper describes the analysis, design, and silicon-fabrication of a fluidic proportional amplifier, which is the most important element of fluidic logic circuits. First, FEM(finite element method) analyses were performed, using the Fluent computational fluid dynamics program, and design geometries were optimized. Then, a $40\;{\mu}m$-deep amplifier was fabricated in silicon using anisotropic dry etching.

• 한국해양공학회지
• /
• 제18권6호
• /
• pp.29-36
• /
• 2004

Floating breakwaters have been recently studied to reduce the transmission ratio of wave energy. The numerical study shows how wave pressure and stress act on the rectangular floating breakwater under various regular wave conditions. In order to evaluate hydrodynamic pressure on the floating breakwater, the infinite element is applied to the linear wave diffraction and radiation problems. SAP2000, a structural analysis program, is used to evaluate stress on the floating breakwater.

• 한국소음진동공학회논문집
• /
• 제15권3호
• /
• pp.251-258
• /
• 2005

The free vibration of a spinning flexible disk-spindle system supported by hydro dynamic bearings (HDB) in an HDD is analyzed by FEM. The spinning flexible disk is described using Kirchhoff plate theory and von Karman non-linear strain, and its rigid body motion is also considered. It is discretized by annular sector element. The rotating spindle which includes the clamp, hub, permanent magnet and yoke, is modeled by Timoshenko beam including the gyroscopic effect. The flexible supporting structure with a complex shape which includes stator core, housing, base plate, sleeve and thrust pad is modeled by using a 4-node tetrahedron element with rotational degrees of freedom to satisfy the geometric compatibility. The dynamic coefficients of HDB are calculated from the HDB analysis program, which solves the perturbed Reynolds equation using FEM. Introducing the virtual nodes and the rigid link constraints defined in the center of HDB, beam elements of the shaft are connected to the solid elements of the sleeve and thrust pad through the spring and damper element. The global matrix equation obtained by assembling the finite element equations of each substructure is transformed to the state-space matrix-vector equation, and the associated eigen value problem is solved by using the restarted Arnoldi iteration method. The validity of this research is verified by comparing the numerical results of the natural frequencies with the experimental ones. Also the effect of supporting structures to the natural modes of the total HDD system is rigorously analyzed.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 추계학술대회논문집
• /
• pp.572-578
• /
• 2003

The free vibration of a spinning flexible disk-spindle system supported by hydro dynamic bearings in a HDD is analyzed by FEM. The spinning flexible disk is described using Kirchhoff plate theory and von Karman non-linear strain, and its rigid body motion is also considered. It is discretized by annular sector element. The rotating spindle which includes the clamp, hub, permanent magnet and yoke, is modeled by Timoshenko beam including the gyroscopic effect. The flexible supporting structure with a complex shape which includes stator core, housing, base plate, sleeve and thrust pad is modeled by using a 4-node tetrahedron element with rotational degrees of freedom to satisfy the geometric compatibility. The dynamic coefficients of HDB are calculated from the HDB analysis program, which solves the perturbed Raynolds equation using FEM. Introducing the virtual nodes and the rigid link constraints defined in the center of HDB, beam elements of the shaft are connected to the solid elements of the sleeve and thrust pad through the spring and damper element. The global matrix equation obtained by assembling the finite element equations of each substructure is transformed to the state-space matrix-vector equation, and the associated eigenvalue problem is solved by using the restarted Arnoldi iteration method. The validity of this research is verified by comparing the numerical results of the natural frequencies with the experimental ones. Also the effect of supporting structures to the natural modes of the total HDD system is rigorously analyzed.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
• /
• pp.399-402
• /
• 1999

This study is about seismic performance of the EDF(Electricite De France) system, that is among various base isolator. We get solutions of equation of motion of this system for displacement, velocity, acceleration and compared with solutions using finite element program. And, through shaking table tests we will prove seismic performance