• Title/Summary/Keyword: structural topology design

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Yaw Gearbox Design for 4MW Class Wind Turbine (4MW급 풍력발전기용 요 감속기 설계)

  • Lee, Hyoung-Woo;Kim, In-Hwan;Lee, Jae-Shin
    • Journal of Convergence for Information Technology
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    • v.12 no.2
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    • pp.142-148
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    • 2022
  • In this paper, the weight reduction design of the yaw gearbox for wind turbine was performed through the finite element analysis method, and the stability was checked by performing the critical speed analysis. The weight reduction product can improve engine efficiency, save parts materials, and earn economic benefits. The yaw gearbox is lightweighted with the goal of achieving a safety rate of 1.3 or higher for wind turbine as indicated by IEC61400-1. In order to reduce the weight of the carrier, a topology optimization method was performed. The safety factor was verified by performing finite element analysis on the carrier. In addition, the housing and carrier were modeled using the finite element method, and the gear train was modeled using MASTA. For the yaw gearbox, the housing and carrier FE model and the gear train model were connected by the partial structural synthesis method to perform the rotational vibration analysis. Vibration excitation sources are mass unbalance and gear mesh frrequemcy, and as a result of the critical speed analysis, it was found that there was no resonance within the operating speed range.

Fatigue Constrained Topological Structure Design Considering the Stress Correction Factor (응력 수정 계수를 고려한 피로 제약 조건 구조물의 위상최적설계)

  • Kim, Daehoon;Ahn, Kisoo;Jeong, Seunghwan;Park, Soonok;Yoo, Jeonghoon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.2
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    • pp.97-104
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    • 2018
  • In this study, a structure satisfying the fatigue constraint is designed by applying the topology optimization based on the phase field design method. In order to predict life based on the stress value, high cycle fatigue failure theory in which stress acts within the range of elastic limit is discussed and three fatigue theories of modified-Goodman, Smith-Watson-Topper and Gerber theory are applied. To calculate the global maximum stress, a modified P-norm stress correction method is used. As a result, it is possible to obtain topology optimization results that minimize the volume while satisfying the fatigue constraints. By applying the phase field design method, a simple shape with a minimized gray scale was obtained, and the maximum stress value acting on the optimization result became very close to the allowable stress value due to the modified P-norm stress method. While previous studies does not consider the stress correction factor, this study proposes the determination method regarding the stress correction factor considering loading effects related to axial stress components.

Structural Analysis and Design of B-pillar Reinforcement using Composite Materials (복합소재를 활용한 B필러 강화재의 구조해석 및 설계)

  • Kang, Ji Heon;Kim, Kun Woo;Jang, Jin Seok;Kim, Ji Wook;Yang, Min Seok;Gu, Yoon Sik;Ahn, Tae Min;Kwon, Sun Deok;Lee, Jae Wook
    • Composites Research
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    • v.34 no.1
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    • pp.35-46
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    • 2021
  • This paper aims to reduce weight by replacing the reinforcements of the B-pillar used in vehicles with CFRP(Carbon Fiber Reinforced Plastics) and GFRP(Glass Fiber Reinforced Plastics) from the existing steel materials. For this, it is necessary to secure structural stability that can replace the existing B-pillar while reducing the weight. Existing B-pillar are composed of steel reinforcements of various shapes, including a steel outer. Among these steel reinforcements, two steel reinforcements are to be replaced with composite materials. Each steel reinforcement is manufactured separately and bonded to the B-pillar outer by welding. However, the composite reinforcements presented in this paper are manufactured at once through compression and injection processes using patch-type CFRP and rib-structured GFRP. CFRP is attached to the high-strength part of the B-pillar to resist side loads, and the GFRP ribs are designed to resist torsion and side loads through a topology optimization technique. Through structural analysis, the designed composite B-pillar was compared with the existing B-pillar, and the weight reduction ratio was calculated.

A Comparison of the Form-Finding Method of Tensegrity Structures (텐세그리티 구조물의 형상탐색 기법 비교)

  • Lee, Seunghye;Lee, Jaehong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.4
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    • pp.313-320
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    • 2014
  • A tensegrity structure consists of a set of continuous cables in tension and a set of discontinuous struts in compression. The tensegrity structure can be classified into self-stressed and pre-stressed pin-jointed structure. A key step in the design of tensegrity structures is the determination of their equilibrium configuration, known as form-finding. In this paper, three effective methods are presented for form-finding of tensegrity structures. After performing form-finding process, a set of force density and corresponding topology results can be obtained. Then the force density method combined with a genetic algorithm is adopted to uniquely define a single integral feasible set of force densities. Numerical examples are presented that demonstrate the excellent performance of the algorithms.

Analysis of key elements of single-layer dome structures against progressive collapse

  • Zhang, Qian;Huang, Wenxing;Xu, Yixiang;Cai, Jianguo;Wang, Fang;Feng, Jian
    • Steel and Composite Structures
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    • v.42 no.2
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    • pp.257-264
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    • 2022
  • The analysis of the progressive collapse resistance of structures is a well-known issue among structural engineers. Large-span reticulated dome structures are commonly utilized in large public buildings, necessitating research into their progressive collapse resistance to assure user safety. The most significant part of improving the structural resilience of reticulated domes is to evaluate their key elements. Based on a stiffness-based evaluation approach, this work offers a calculating procedure for element importance coefficient. For both original and damaged structures, evaluations are carried out using the global stiffness matrix and the determinant. The Kiewitt, Schwedler, and Sunflower reticulated domes are investigated to explore the distribution characteristic of element importance coefficients in the single-layer dome structures. Moreover, the influences of the load levels, load distributions, geometric parameters and topological features are also discussed. The results can be regarded as the initial concept design reference for single-layer reticulated domes.

Material Topology Optimization of FGMs using Homogenization and Linear Interpolation Methods (균질화 및 선형보간법을 이용한 기능경사 내열복합재의 물성분포 최적설계)

  • 조진래;박형종
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.4
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    • pp.495-503
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    • 2001
  • In a functionally graded materials(FGM), two constituent material particles are mixed up according to a specific volume fraction distribution so that its thermoelastic behavior is definitely characterized by such a material composition distribution. Therefore, the designer should determine the most suitable volume fraction distribution in order to design a FGM that optimally meets the desired performance against the given constraints. In this paper, we address a numerical optimization procedure, with employing interior penalty function method(IPFM) and FDM, for optimizing 2D volume fractions of heat-resisting FGMs composed of metal and ceramic. We discretize a FGM domain into finite number of homogenized rectangular cells of single design variable in order for the optimization efficiency. However, after the optimization process, we interpolate the discontinuous volume fraction with globally continuous bilinear function in order to enforce the continuity of volume fraction distributions.

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Isogeometric Optimal Design of Kelvin Lattice Structures for Extremal Band Gaps (극대화된 밴드갭을 갖는 켈빈 격자 구조의 아이소-지오메트릭 최적 설계)

  • Choi, Myung-Jin;Oh, Myung-Hoon;Cho, Seonho;Koo, Bonyong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.4
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    • pp.241-247
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    • 2019
  • A band gap refers to a certain frequency range where the propagation of mechanical waves is prohibited. This work focuses on engineering three-dimensional Kelvin lattices having external band gaps at low audible frequency ranges using a gradient-based design optimization method. Elastic wave propagation in an infinite periodic lattice is investigated by employing the Bloch theorem. We model the ligaments using a shear-deformable beam model obtained by consistent linearization in a geometrically exact beam theory. For a given lattice topology, we enlarge band gap sizes by controlling the configuration of the beam neutral axis and cross-section thickness that are smoothly parameterized by B-spline basis functions within the isogeometric analysis framework.

The Cognitive Ecological Characteristics in Folded Space and Their Effects (폴드공간의 인지생태론적 특성과 그 효과)

  • Kim Joomi
    • Korean Institute of Interior Design Journal
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    • v.14 no.3 s.50
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    • pp.181-190
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    • 2005
  • In accordance with the rapid growth of digital media in 1990s, the state of indetermination that is found in digital process has been emphasized in the field of natural science and philosophy. Digitalized space design has been dramatically developed and it raised heated debate and comment on 'folded space' The purpose of this thesis is to explore how the cognitive-ecological factors constitute fold structures in space design of the late 20th century. Syntax of space structure and geometric composition were analyzed to define what types of cognitive-ecological factors are contrived in the process of visual information. In particular, I put higher theoretical emphasis on what characteristics are ensued in the process of structuring spaces than any other subjects. Through theses analyses and discussions, I raised questions on what principles are operating to create new space design that counts on non-linear structure and its formational process. And I also observed what influences these structural principles of design could fundamentally bring to human beings. First, I proposed that we could overcome reductionist space design through cognitive-ecological approach. Some key concepts such as affordance, parallel processing, and redundancy were adopted as defining elements of non-linear structures. As a result of analyses, I found that the cognitive-ecological approach could substitute the reductionist space design of the past. What is also found is that the three variables are the ultimate ecological elements. In addition, as a methodological concept of fold structures, the form of 'topology' was highlighted because it could be a supporting idea to the cognitive-ecological factors. Second, I claimed that non-linear design is more experiential than rational linear design, and it is more efficiently correspondent to human being than any other forms. What is intended and implied in non-linear structure is also indicated.

Typology as Form Generating Process in Contemporary Architecture (현대건축 형태생성 과정으로써의 유형학적 특성)

  • Kim, Jong-Myeong;Kim, Dong-Jin
    • Korean Institute of Interior Design Journal
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    • v.23 no.5
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    • pp.3-13
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    • 2014
  • Typology in Contemporary Architecture wants to escape from the classical typology that has the problems about specific program of structuralism, typical repeatation of customary form. As visible and non-visible things are appeared in contemporary architecture through the analysis of the inner system involving development process of changing itself, typology of contemporary is utilized at a tool of form generation in the process of architect. And it notes that the structural properties of the building system. The form of contemporary architecture has the new connecting strucure not reduced to existing ones. It carries out generative access as a device in order to solve the complexity of society. From this perspective, we analyze the process of projects of contemporary architects that can be typological strategy not representation of post geometric form but a tool of form generation in architectural process. As a result, we can find four characteristics of typology as a tool of form generation; 'interference and mix of program', 'continous slabs', 'rearrangement through relationship setting', 'transformation of multi-layers'. These are expanding to the process that reflect history and context or infer from morphology. Therefore, typology as architectural process of form generation overcomes morphological typology of classical typology and suggests that the different architectural approach having potential possibility.

Two Algorithms for Constructing the Voronoi Diagram for 3D Spheres and Applications to Protein Structure Analysis (삼차원 구의 보로노이 다이어그램 계산을 위한 두 가지 알고리듬 및 단백질구조채석에의 응용)

  • Kim D.;Choi Y.;Kim D.S.
    • Korean Journal of Computational Design and Engineering
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    • v.11 no.2
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    • pp.97-106
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    • 2006
  • Voronoi diagrams have been known for numerous important applications in science and engineering including CAD/CAM. Especially, the Voronoi diagram for 3D spheres has been known as very useful tool to analyze spatial structural properties of molecules or materials modeled by a set of spherical atoms. In this paper, we present two algorithms, the edge-tracing algorithm and the region-expansion algorithm, for constructing the Voronoi diagram of 3D spheres and applications to protein structure analysis. The basic scheme of the edge-tracing algorithm is to follow Voronoi edges until the construction is completed in O(mn) time in the worst-case, where m and n are the numbers of edges and spheres, respectively. On the other hand, the region-expansion algorithm constructs the desired Voronoi diagram by expanding Voronoi regions for one sphere after another via a series of topology operations, starting from the ordinary Voronoi diagram for the centers of spheres. It turns out that the region-expansion algorithm also has the worst-case time complexity of O(mn). The Voronoi diagram for 3D spheres can play key roles in various analyses of protein structures such as the pocket recognition, molecular surface construction, and protein-protein interaction interface construction.