기존 지하철정거장 비개착공법 적용시 유한요소 해석과 관리기준에 관한 연구

조병준 한국방재안전학회 2019 한국방재안전학회 논문집 Vol.12 No.4

지하철 정거장의 하부에 비개착공법 적용하여 안정성 영향분석을 위하여 유한요소 변위 해석, 유한요소 응력해석, 강관추진 진행 과정에 따른 변위, 내부 굴착에 따른 변위 및 강관의 응력변화, 지반의 물리적 특성인 탄성 및 탄소성 이론 등을 도입하였다. 구조적으로적당한 미소 요소로 분할해서 각 요소가 유한개의 점으로 연결되는 요소로 가정한 모델로 하여 수치적 해석을 통하여 비개착공법 적용시 구조물 안정성에 미치는 영향을 국토교통부와 외국 자료를 근간으로 한 구조물 관리기준과 비교 검토하였다. 그 결과 최대 변위7.21 mm가 발생되어 허용변위 기준(25.00 mm) 이내, 최대 각 변위는 1/3,950으로 허용 각변위 기준(1/500) 이내, 비개착공법 강관다발구조체의 최대 휨압축응력량도 70.29 MPa로 허용기준(210.00 MPa) 이내로 분석되었고, 최대 전단응력량은 47.38 MPa로 허용기준(120 MPa) 이내로 분석되어 유한요소 해석결과, 설계 및 시공 안정성을 검증하였다. To analyze the influence on the stability, resulting from application of upgrade pipe roof structure (UPRS) method to the structure existed under subway Station, physical properties of a ground, elasticity and elasto-plastic theories, including displacement analysis of finite elements, stress analysis of finite elements, displacement caused by steel pipe propulsion and internal excavation, and stress change in a steel pipe, were introduced. Then, the influence on structural stability when applying the UPRS method was compared and reviewed based on the construction management standard of the Ministry Land, Infrastructure and Transport and foreign sources, using numerical analysis with a model which assumes that each microelement divided into a structurally stable point consists of the connection of finite points. As a result of the finite element analysis, 7.21 mm maximum displacement, 1/3,950 angular displacement, 70.28 MPa bending compressive stress of steel pipe structure constructed with UPRS (non-excavation) method and 477.38 MPa maximum shear strength were within their allowable standards (25.00 mm, 1/500, 210.00 MPa and 120.00 MPa, respectively), and therefore, the results showed that the design and construction are stable.

가동물체형 파력발전장치 Arm 구조물의 구조해석

김현성(Hyun-Sung Kim),김병완(Byoung Wan Kim),하윤진(Yoon-Jin Ha),박지용(Ji Yong Park) 한국해양환경·에너지학회 2021 한국해양환경·에너지학회 학술대회논문집 Vol.2021 No.10

기존 에너지원들의 대체제로서 여러 종류의 친환경 에너지에 대한 연구·개발이 진행되고 있으며, 특히 넓은 공간과 풍부한 에너지원이 활용 가능한 해양환경에서의 에너지 발전이 크게 증가하고 있다. 이 중 파랑의 운동에너지와 위치에너지를 이용하여 발전을 하는 파력발전의 경우 파고가 높고 파주기가 긴 해역에서 적절한 발전으로 여러 형태의 발전 형태를 가진다. 본 연구에서는 가동물체형 파력발전장치의 arm 구조물의 파랑 중 구조적 특성을 평가하였다. 가동물체형 파력발전장치는 부유체, arm 구조물, 지지구조물로 구성되며, 부유체의 운동를 통해 발전하게 된다. 효율적 발전을 위해 PTO 감쇠를 통해 부유체의 운동을 제어하며, 이에 따라 지지구조물과 부유체를 연결하는 Arm 구조물은 부유체에 작용하는 파랑하중과 PTO에 의한 감쇠 하중 조건에서 충분한 구조안전성을 가지도록 설계되어야 한다. 고차경계요소법(Higher-Order Boundary Element Method, HOBEM)을 활용하여 부유체에 작용하는 파랑하중을 산정하였다. Arm 구조물의 구조해석의 경우 유한요소법(Finite Element Method, FEM)을 적용하였으며, 구조물은 쉘 요소로 모델링되었다. 규칙파 조건에서의 해석을 통해 응력 RAO(Response Amplitude Operator) 결과를 구하였으며, 이를 통해 Arm 구조물의 구조적 특성을 확인하고자 하였다. The research and development on various renewable energy generations are being in progress as the substitute for existing energy sources. Especially, energy generations at offshore environment are increasing significantly because vast space and abundant energy source are available in the offshore site. Wave energy generation produces electricity using kinetic and potential energies and has various generation types. In this study, the structural characteristic of arm structure for oscillating body type wave energy converter is evaluated. Oscillating body type wave energy converter consists of a floater, arm structure, and support structure, and generates energy using heave motion of floater. For efficient energy generation, the motion of floater is controlled by PTO damping. Arm structure should have sufficient structural safety in loading conditions in which wave loads on floater and damping force by PTO equipment are applied. Wave loads on the floater are estimated by applying HOBEM(Higher-Order Boundary Element Method). Structural analyses on arm structure are conducted by FEM(Finite Element Method), and the structure is modeled to shell elements. Through the analyses in regular wave conditions, stress RAO(Response Amplitude Operator) results on arm structure are obtained, and thus structural characteristic of arm structure are reviewed.

일반화 전달강성계수법을 이용한 트러스 구조물의 구조해석

최명수(M. S. Choi),문덕홍(D. H. Moon),Y. Bonkobara,T. Kondou,T. Ayabe 한국동력기계공학회 2005 한국동력기계공학회 학술대회 논문집 Vol.- No.-

In structural analysis of machine and structure, the finite element method (FEM) is most widely used and powerful analysis algorithm. But the FEM has much computational cost to solve the structural analysis problem of system with many degrees of freedom. For overcoming the drawback of the FEM, authors suggested the transfer stiffness coefficient method (TSCM) which was based on the transfer of the stiffness coefficient for analytical system. However the TSCM was not suitable to analyzing a variety of truss structures. In this paper, the structural analysis algorithm for truss structures is formulated by the generalized TSCM (GTSCM) which combines the graph theory and the TSCM. The validity of the GTSCM is confirmed through the comparision of computational results by the GTSCM and the FEM.

유한요소법 및 반응표면법 기반 대면적 양면형 태양광 모듈 프레임 최적설계

한동운(Han Dongwoon),김성탁(Kim Seongtak) 한국태양에너지학회 2023 한국태양에너지학회 논문집 Vol.43 No.6

Large-scale bifacial photovoltaic modules have the advantages of high unit yield and production. Because the module weight increases with the module size, the power conversion efficiency can decrease owing to defects such as encapsulant delamination and cell cracking caused by the increased deflection of the module. However, research on the design optimization of large-scale bifacial photovoltaic module frames is lacking. Therefore, in this study, we analyzed the deflection of large-scale bifacial photovoltaic modules using finite element analysis (FEA). Furthermore, we propose an optimal design for a solar module frame that minimizes both module deflection and frame weight using the response surface methodology (RSM). We established 32 experimental setups utilizing the design of experiments with five frame shape factors placed at two levels each. The results of structural analysis showed that the maximum deflection occurred at the center of the module. The results obtained using RSM for minimizing deflection and weight yielded optimal factors as follows: a, b, c, d, e were found to be 1.9 ㎜, 14.0 ㎜, 1.5 ㎜, 1.7 ㎜, and 2.5 ㎜, respectively. A comparison of the deflection and weight between the existing and optimal conditions obtained from structural analysis revealed an increase in weight of approximately 4.5% compared to the existing conditions. Simultaneously, a deflection reduction of approximately 15.8% was observed.

장간조립교의 다양한 구조형태에 대한 안전성 평가

이준혁,정선우,김동윤,허장욱 한국기계가공학회 2023 한국기계가공학회지 Vol.22 No.10

A panel bridge is a military bridge with a modular structure designed to overcome obstacles or provide supportequipment during military operations. They exhibited various structural forms. The NATO standard Military LoadClass (MLC) was applied to assist in the selection of different panel bridge structures and evaluate their stabilityand performance. In this study, structural analyses were performed on six different bridge models, including thebasic single-step double-lane and single-step triple-lane structures by applying the standard load of MLC-trackedvehicles to each bridge model. Additional truss heat is effective for displacement-sensitive structures, whereasadditional stiffeners are suitable for equivalent and shear-sensitive structures. These results affect the structuralselection and design of long-term assembly bridges and can provide useful information for evaluating structuralstability and performance.

실험계획법을 이용한 미니로더의 최적설계

권기범(Ki-Beom Kwon),신대영(Dea-Young Shin) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.6

본 연구에서는 미니로더의 유압시스템을 모델링 하였고, 시뮬레이션 결과와 실제 실험 결과의 비교를 통해 시뮬레이션의 타당성을 검증하였다. 그리고 미니로더의 유압시스템 해석을 통해 구성부품에 가해지는 하중을 구하였으며, 그 하중데이터를 바탕으로 구조해석을 진행하여 구조안전성을 평가하였다. 구조해석결과 강도 향상이 필요하다고 판단되는 main frame에 대해서는 실험계획법을 이용하여 중량은 유지하면서도 강도는 향상시킬 수 있는 최적 설계치수를 제안하였다. In this study, a hydraulic system of a mini-loader is modeled, and the model is validated by comparing the simulation results to the experimental results. A load force acting on the structure of the mini-loader is obtained from the simulation of the hydraulic system, and the structural analysis via finite element method is performed using the obtained load force to evaluate the structural safety of the loader. For the mainframe that requires additional strengthening according to the structural analysis, the optimum design parameters are proposed using the design of experiments to improve strength without additional mass.

자기누설검출법을 이용한 금속 표면결함 검출시스템 설계적정성 검토

박용희,이창우,안현준,김동욱,이재혁,이주섭 대한기계학회 2019 大韓機械學會論文集A Vol.43 No.8

Magnetic Flux Leakage is used to detect corrosion, defects, and mechanical deformation of steel products by detecting the magnetic leakage signal on them due to the change in shape. After the steel product is magnetized by a permanent magnet, a hall sensor is generally used to detect the signals. This technology has been developed to inspect gas pipelines and domestic piping. However, other industries such as steel plants and automobile industries have started to apply it to secure the robustness and structure of steel products. The present study used the finite element method to analyze the defects on the thick plate of a novel machine having rotating kinematics. Two engineering problems were solved by the fact that the distribution of magnetic leakage signal depends on the shape of defect. First, the magnetic leakage signal and force between the machinery and plate were analyzed by changing the design of magnetic sensor. Second, the dynamic characteristics of the rotating kinematics were checked. Especially, coupled electromagnetic-structural analysis was used to solve the multi-physics problem. 자기누설 탐상법은 금속재 내·외부에 존재하는 부식, 결함 또는 기계적 변형을 탐지하기 위한 비파괴검사 중 하나로 투자율이 큰 금속재에 자기장을 형성하고 결함이 있는 부분에 발생하는 누설 자속 신호를 홀센서로 검출하는 방식이 보편화되어 있다. 국내에서는 노후화된 강관 또는 배관의 결함 검출을 위한 장비개발에 중점 투자해왔으나, 최근 금속 구조물의 건전성 확보가 주요해지면서 철강, 에너지 플랜트, 자동차 부품 등 산업 전반에 걸쳐 자기누설 탐상기술 적용이 이루어지고 있는 상태다. 본 논문에서는 철강제품 중 하나인 후판의 표면결함 검출을 위해 개발한 회전식 검출시스템의 설계 타당성 검토를 수행하였다. 결함형상에 따른 자기누설변화 이해를 토대로, 자기센서 케이스 설계에 따른 누설 자기량 및 전자기력 변화와 회전식 전달부 진동특성의 두 가지 공학 문제에 대해 유한요소해석과 전자기-구조 연성 해석법을 이용하여 검출장비 설계 타당성 검토방안을 제안하였다.

SUV용 액슬의 소음원 규명 및 소음 저감을 위한 액슬의 구조변경에 관한 연구

이주영(Lee, Ju-Young),조윤경(Jo, Yoon-Kyeong),김종연(Kim, Jong-Youn),이상권(Lee, Sang-Kwon) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.6

This paper presents experimental and analytic methods to reduce interior noise generated by car axle. The test vehicle has a whine noise problem at passenger seats. In order to identify transfer path of interior axle noise, the vibration path analysis, the modal analysis and running modal analysis are systematically employed. By using these various methods, it has been founded that the interior noise generated by car axle was air borne noise. To reduce and predict axle noise, various structural modifications are performed by using FEM and BEM techniques, respectively. Through the modification of the axle structure, the air borne noise of the axle was reduced 3$\sim$4 dBA level.

강성계수의 전달에 의한 평판 구조물의 구조해석

최명수(Myung-Soo Choi),장덕종(Duck-Jong Jang  ),여동준(Dong-Jun Yeo),문덕홍(Deok-Hong Moon) 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-

The structural analysis algorithm of a rectangular plate structure is formulated by using the finite element-transfer stiffness coefficient method (FE-TSCM). This method is based on the concept of the successive transmission of the transfer stiffness coefficient method and the modeling technique of the finite element analysis. In order to confirm the validity of the FE-TSCM, bending structural analysis for a rectangular plate is carried out on a personal computer by using the FE-TSCM and the finite element method (FEM). The effectiveness of the FE-TSCM from the viewpoint of computational cost is demonstrated by comparing computational results of the FE-TSCM and the FEM.

전달강성계수법에 의한 격자형 구조물의 강제진동 해석

문덕홍,최명수 한국소음진동공학회 1998 소음 진동 Vol.8 No.5

Complex and large lattice type structures are frequently used in design of bridge, tower, crane and aerospace structures. In general, in order to analyze these structures we have used the finite element method(FEM). This method is the most widely used and powerful method for structural analysis lately. However, it is necessary to use a large amount of computer memory and computational time because the FEM requires many degrees of freedom for solving dynamic problems exactly for these complex and large structures. For analyzing these structures on a personal computer, the authors developed the transfer stiffness coefficient method(TSCM). This method is based on the concept of the transfer of the nodal dynamic stiffness coefficient matrix which is related to force and displacement vector at each node. And we suggested TSCM for free vibration analysis of complex and large lattice type structures in the previous report. In this paper, we formulate forced vibration analysis algorithm for complex and large lattice type structures using extened TSCM. And we confirmed the validity of TSCM through computational results by the FEM and TSCM, and experimental results for lattice type structures with harmonic excitation.