• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.75-77
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• 2004

본 논문에서는 레그 익스텐션 기구의 안정성을 평가하기 위하여 3차원 유한요소 해석 코드인 ANSYS를 활용하여 구조해석을 실시하였다. 레그 익스텐션 기구를 제작함에 있어서 기존의 기구를 보완하고 운동효과의 향상, 안정성을 고려하여 설계하였다. 또한 레그 익스텐션 기구의 회전봉의 각도를 $0^{\circ}\~360^{\circ}$까지 회전가능하게 설계하여 운동하는 사람의 운동 강도를 조절할 수 있는 새로운 기구를 설계하였다.

• Journal of the Korea Society for Simulation
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• v.27 no.1
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• pp.101-109
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• 2018

Field experiments as well as numerical analyses with finite element analysis codes are two valuable and complemental ways to understand the structural response under explosive blast load. However, there seems to be only limited information available about finite element analysis and experimental validation on the response of structural components under internal explosions. For complementary use of the two ways, the numerical analyses should be validated with field experiments by comparing their results. In this paper, a small-scaled reinforced concrete building with a room is employed for experimental investigations. An amount of TNT is detonated at the center of the room. Pressure at three different sites in the room, displacement of centers of two walls, and damage patterns of four walls are measured and compared to results from numerical analyses. The experimental results are much similar to the numerical analyses results. The finite element analysis code ANSYS AUTODYN is employed to numerically analyze both pressure distribution inside the room and response of walls subjected to blast pressure. The feasibility and validity of the numerical analysis on the reponses of structural components under internal explosions are discussed in terms of structural damage assessment, and evaluated as the same damage in the analysis and the experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.67-74
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• 2002

The paper deals with a fully assumed strain soild element that can be used for modeling of thin sensors and actuators. To solve fully coupled field problems, the eledtric potential is regarded as a nodal degree of freedom in addition to three translations in an eighteen node assumed strain soild element. Therefore, the induced electric potential can be calculated for a prescribed load and the actuation displacement can be computed for an input voltage. Since the assumed strain solid element can alleviate locking. A finite element code is developed based on the formulation and typical numerical examples are solved for code validation. Using the code, we have conducted parametric study for THUNDER actuator. It is found that a particular combination of materials for layer curvature of THUNDER improves the actuation displacement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.29-30
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• 2002

본 연구에서는 Boeing사에서 개발한 EASY5 프로그램을 이용하여 터보팬 엔진을 모델링하고 성능해석을 수행하였다. 연구대상 엔진인 BR715-56 엔진은 추력이 20,000lbf급인 2 스풀 터보팬 엔진으로 분리흐름(Separate Flow) 형이다. 엔진은 팬, 압축기, 연소기, 저압터어빈, 압축기터어빈, 팬 노즐 및 Core 노즐로 구성되어 있으며 Station No.는 Fig 1과 같다. 연구에 사용된 EASY5 프로그램은 동역학 시스템을 모델링하고 해석하는 프로그램으로, 제공되는 라이브러리 구성품을 이용하여 보다 쉽게 동적 시스템을 모델링할 수 있다. 또한 Steady-State Solver를 이용하여 정적 평형상태를 빠른 시간에 찾을 수 있어 보다 빠른 해석을 수행할 수 있다. 또한 해석된 동역학 모델을 FORTRAN이나 C 코드로 생성하여 제공함으로써 프로그램의 수정이나 보완이 용이하고, 제공되지 않은 시스템의 라이브러리 구성품의 경우에는 사용자 정의 코드를 만들어 사용함으로써 프로그램의 기능을 확장할 수 있다. EASy5는 대표적인 제어기 설계 소프트웨어인 MATLAB, MATRIX-x와의 호환도 가능하며 NASTRAN등과 같은 유한요소 해석 프로그램과의 데이터 공유도 가능하여 보다 폭 넓은 시스템 모델링과 제어기 설계도 쉽게 할 수 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.823-830
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• 1998

본 연구에서는 미국, 프랑스, 일본의 고온구조 설계지침서의 크립-피로 손상평가 방법을 살펴보고 고온하중을 받는 불연속 구조물에 대하여 범용 유한요소 해석코드인 ANSYS와 ABAQUS를 이용한 열전달 및 응력해석을 수행하여 각국의 코드 절차에 따른 크립-피로 손상 평가를 하였다. 이들 결과를 점소성 비탄성 구성식을 적용한 비탄성해석 결과와 비교평가하였다. 본 연구에서 분석한 불연속 구조물의 경우에 대한 평가 결과 미국의 ASME Subsection NH에 의한 방법이 비탄성 해석결과에 가장 가까운 결과를 주며, 일본의 BDS에 따른 평가방법은 적용성이 가장 편리함을 알 수 있었다.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.898-910
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• 1995

기존경수로 핵연료의 연소도를 크게 증가시키는 고연소도 핵연료 및 미래형 핵연료에서는 연료봉의 축방향 조사성장이 증가하게 되고 이와 같이 증가된 축방향 연료봉 성장을 수용하기 위해서는 상.하단 고정체 사이의 간격이 더 필요하게 된다. 이 요구되는 상.하단고정체 사이의 축방향 공간을 얻기 위하여 기존 국산핵연료 하단고정체 유로판 및 이물질여과 하단고정체에 대하여 응력강도를 기준으로 두께최적화 계산을 수행하였다. 계산은 범용 유한요소 코드인 ANSYS 코드를 이용하였다. 이 두께 최적화에 의해 기존의 국산 17$\times$17 경수로 핵연료의 하단고정체에서는 지지 Leg의 폭과 길이를 증가시킴으로써 유로판의 두께 감소를 약 5.1mm 줄일 수 있음을 알 수 있고, DRBEP용 하단고정체에서는 약 4.6mm의 두께 감소가 가능한 것으로 해석되었다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.3
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• pp.825-831
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• 1996

Using the two-dimensional hydrocode HI-DYNA2D, a calculation on the explosive selding of dissimilar plates(Steel Titanium) was made for the pressure, temperature, velocity and impact ingles adjacent to the collision point during the welding process. The FEM result indicates that optimal stand-off distance of initially parallel set-up is 3-5mm for various values of the explosive thickness. The calculation shows that when the explosive thickness is around 30mm, the temperature of welding point which is strongly related to the metallic jet formation is 2, 000-3, 500K for the given stand-off distance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.3
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• pp.295-304
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• 2000

To evaluate the structural integrity for the strainer under seismic loading the seismic analysis and design were performed for T-type strainer in accordance with ASME, Section Ⅲ, Class 3(ND). Since there are no specified design requirements for the strainer in ASME Code, the strainer body was analysed according to ND-3500, valve design. Flanged joints connected with PCS piping were designed according to ND-3658.3. And the criteria for the cover flange was governed by the Appendix XI. Both a frequency analysis and an equivalent static seismic analysis of the strainer were carried out using the finite element computer program, ANSYS. The frequency analysis results show the fundamental natural frequency is greater than 33Hz, thus justifying the use of the equivalent static analysis through which membrane and bending stresses are obtained in the critical points near the branch connection area. The results of the seismic evaluation fully satisfied with the structural acceptance criteria of the ASME Code. Accordingly the structural integrity on the strainer body and flanges were proved.

• Journal of the Society of Disaster Information
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• v.12 no.1
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• pp.1-9
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• 2016

Local wall thinning elbow due to the water flow is one of the main degradation phenomenon in carbon steel pipe of plant system. The API579 code of FFS (fitness for service) used in the chemical plant gives a guideline to protect local wall thin problem in a straight pipe, but it does not include an elbow. In this study, the locally wall thinned elbow, which is considered an extrados or intrados wall thinned elbow, was carried out considering in-plane or out-plane bending using FEM (finite element method) analysis, and some of results were also compared with the experimental data. The results could give the structure integrity assessment to protect the local wall thinned elbow.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.3
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• pp.299-307
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• 2007

In this study, a new concept for simulating a physical damage of tunnel shotcrete lining due to a long-term chemical deterioration has been proposed. It is known that the damage takes place mainly by internal cracks, reduction of stiffness and strength, which results mainly from volume expansion of the lining and corrosion of cement materials, respectively. This damage mechanism of shotcrete lining appears similar in most kinds of chemical reactions in tunnels. Therefore, the mechanical deterioration mechanism induced by a series of chemical reactions was generalized in this study and mathematically formulated in the framework of thermodynamics. The numerical model was implemented to a 3D finite element code, which can be used to simulate behaviour of tunnel structures undergoing external loads as well as chemical deterioration in time. A number of illustrative examples were given to show a feasibility of the model in tunnel designs.