• Title/Summary/Keyword: structural topology design

검색결과 243건 처리시간 0.022초

인력선 프레임의 병렬화 위상 최적설계 (Parallelized Topology Design Optimization of the Frame of Human Powered Vessel)

  • 김현석;이기명;김민근;조선호
    • 대한조선학회논문집
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    • 제47권1호
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    • pp.58-66
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    • 2010
  • Topology design optimization is a method to determine the optimal distribution of material that yields the minimal compliance of structures, satisfying the constraint of allowable material volume. The method is easy to implement and widely used so that it becomes a powerful design tool in various disciplines. In this paper, a large-scale topology design optimization method is developed using the efficient adjoint sensitivity and optimality criteria methods. Parallel computing technique is required for the efficient topology optimization as well as the precise analysis of large-scale problems. Parallelized finite element analysis consists of the domain decomposition and the boundary communication. The preconditioned conjugate gradient method is employed for the analysis of decomposed sub-domains. The developed parallel computing method in topology optimization is utilized to determine the optimal structural layout of human powered vessel.

Optimum topology design of geometrically nonlinear suspended domes using ECBO

  • Kaveh, A.;Rezaei, M.
    • Structural Engineering and Mechanics
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    • 제56권4호
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    • pp.667-694
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    • 2015
  • The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.

요소 연결 매개법을 이용한 선형 구조물의 동적 컴플라이언스 최적화 (Element Connectivity Based Topology Optimization for Linear Dynamic Compliance)

  • 윤길호
    • 한국전산구조공학회논문집
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    • 제22권3호
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    • pp.259-265
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    • 2009
  • 본 연구 논문에서는 요소 연결 매개법(Element Connectivity Parameterization Method)을 이용하여 선형 구조물의 동적 컴플라이언스(Dynamic compliance)를 최소화하는 위상을 설계하는 기법을 연구한다. 기존의 밀도를 기반으로 한 위상최적화기법은 각 유한 요소의 탄성계수를 각 요소에 정의되어 있는 설계변수(Design Variable)를 이용하여 위상최적화를 수행한다. 이 방법은 현재까지 많은 선형구조문제에 적용되었지만 비선형 문제와 멀티피직스 시스템에서 수치적인 문제점이 보고되었다. 이런 문제점을 근본적으로 해결하기 위하여 최근에 요소 연결 매개법(Element Connectivity Parameterization Method)이란 새로운 최적화 기법이 개발되었다. 이 새로운 설계 방법은 요소의 강성을 설계하는 것이 아니라 요소의 연결성을 설계하는 기법으로 이를 이용하여 비선형 구조물이나 멀티피직스 시스템의 위상최적화를 효과적으로 수행할 수 있다. 하지만, 아직까지 질량 행렬의 정의에 대한 모호함으로 인하여 동적인 구조물의 최적화에 대한 연구가 많이 이루어지지 않았다. 이런 문제점을 해결하기 위하여 요소 연결 매개법에서 질량행렬을 정의하는 방법을 연구하며, 이를 이용하여 선형 구조물의 동적 컴플라이언스(Dynamic Compliance)를 고려한 위상최적화 문제에 적용하여 제안된 방법을 검증하였다.

신뢰성 해석을 이용한 차량 후드 보강재의 위상최적화 (Topology Optimization of the Inner Reinforcement of a Vehicle's Hood using Reliability Analysis)

  • 박재용;임민규;오영규;박재용;한석영
    • 한국생산제조학회지
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    • 제19권5호
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    • pp.691-697
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    • 2010
  • Reliability-based topology optimization (RBTO) is to get an optimal topology satisfying uncertainties of design variables. In this study, reliability-based topology optimization method is applied to the inner reinforcement of vehicle's hood based on BESO. A multi-objective topology optimization technique was implemented to obtain optimal topology of the inner reinforcement of the hood. considering the static stiffness of bending and torsion as well as natural frequency. Performance measure approach (PMA), which has probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints. To evaluate the obtained optimal topology by RBTO, it is compared with that of DTO of the inner reinforcement of the hood. It is found that the more suitable topology is obtained through RBTO than DTO even though the final volume of RBTO is a little bit larger than that of DTO. From the result, multiobjective optimization technique based on the BESO can be applied very effectively in topology optimization for vehicle's hood reinforcement considering the static stiffness of bending and torsion as well as natural frequency.

위상최적설계를 이용한 H형강 부재의 스티프너 형상탐색 (Shape Extraction of Stiffeners of H-beam using Topologically Structural Optimization)

  • 정원식;반 티엔 탄;이동규
    • 한국공간구조학회논문집
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    • 제23권1호
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    • pp.15-23
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    • 2023
  • In this work, we deal with the feasibility of structural topology optimization for beam designs using retrofits that optimally allocates the reinforcement to the web under the condition that designers set bolt regions for H-beams of different dimensions. Mean compliance or minimal strain energy is considered for the optimization. Volume fraction is given to the design space to assign appropriate steel material quantities. The purpose of this study is to evaluate optimal shapes of stiffeners with the maximum rigidity that improves the axial and shear performance of the H-beam and to satisfy a given safety design standard of H-beam and stiffeners in case arbitrary load effect and resistances. Finally, the effectiveness of stiffness-based topology optimization on stiffeners is verified with several practical applicable examples.

The smooth topology optimization for bi-dimensional functionally graded structures using level set-based radial basis functions

  • Wonsik Jung;Thanh T. Banh;Nam G. Luu;Dongkyu Lee
    • Steel and Composite Structures
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    • 제47권5호
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    • pp.569-585
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    • 2023
  • This paper proposes an efficient approach for the structural topology optimization of bi-directional functionally graded structures by incorporating popular radial basis functions (RBFs) into an implicit level set (ILS) method. Compared to traditional element density-based methods, a level set (LS) description of material boundaries produces a smoother boundary description of the design. The paper develops RBF implicit modeling with multiquadric (MQ) splines, thin-plate spline (TPS), exponential spline (ES), and Gaussians (GS) to define the ILS function with high accuracy and smoothness. The optimization problem is formulated by considering RBF-based nodal densities as design variables and minimizing the compliance objective function. A LS-RBF optimization method is proposed to transform a Hamilton-Jacobi partial differential equation (PDE) into a system of coupled non-linear ordinary differential equations (ODEs) over the entire design domain using a collocation formulation of the method of lines design variables. The paper presents detailed mathematical expressions for BiDFG beams topology optimization with two different material models: continuum functionally graded (CFG) and mechanical functionally graded (MFG). Several numerical examples are presented to verify the method's efficiency, reliability, and success in accuracy, convergence speed, and insensitivity to initial designs in the topology optimization of two-dimensional (2D) structures. Overall, the paper presents a novel and efficient approach to topology optimization that can handle bi-directional functionally graded structures with complex geometries.

양방향 진화적 구조최적화를 이용한 신뢰성기반 위상최적화 (Reliability-Based Topology Optimization Based on Bidirectional Evolutionary Structural Optimization)

  • 유진식;김상락;박재용;한석영
    • 한국생산제조학회지
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    • 제19권4호
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    • pp.529-538
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    • 2010
  • This paper presents a reliability-based topology optimization (RBTO) based on bidirectional evolutionary structural optimization (BESO). In design of a structure, uncertain conditions such as material property, operational load and dimensional variation should be considered. Deterministic topology optimization (DTO) is performed without considering the uncertainties related to the design variables. However, the RBTO can consider the uncertainty variables because it can deal with the probabilistic constraints. The reliability index approach (RIA) and the performance measure approach (PMA) are adopted to evaluate the probabilistic constraints in this study. In order to apply the BESO to the RBTO, sensitivity number for each element is defined as the change in the reliability index of the structure due to removal of each element. Smoothing scheme is also used to eliminate checkerboard patterns in topology optimization. The limit state indicates the margin of safety between the resistance (constraints) and the load of structures. The limit State function expresses to evaluate reliability index from finite element analysis. Numerical examples are presented to compare each optimal topology obtained from RBTO and DTO each other. It is verified that the RBTO based on BESO can be effectively performed from the results.

밀도법 기반 위상 최적설계의 실험적 검증 (Experimental Validation of Topology Design Optimization)

  • 차송현;이승욱;조선호
    • 한국전산구조공학회논문집
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    • 제26권4호
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    • pp.241-246
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    • 2013
  • 본 논문에서는 밀도법 기반 위상 최적설계를 통해 얻어진 수치 결과를 바탕으로 CAD 모델을 구성하고 이를 3차원 프린터로 제작하여 실험적으로 최적설계를 검증하였다. 위상 최적설계 과정에서는 체커보드(Checkerboard) 현상이나 잔가지가 종종 나타나는데, 이는 최적설계 구조물을 실제로 제작함에 있어서 어려움을 준다. 이러한 문제점을 해결하기 위하여 민감도 필터링과 모폴로지 기법을 사용하였다. 엄밀한 검증을 위하여 수치 모델과 실험 모델의 부피율을 일치시켰다. 위상 최적설계를 포함한 다양한 설계에 대하여 실험을 통해 비교하여 최적설계 구조물이 가장 높은 강성을 가지고 있음을 확인하였으며 컴플라이언스에 대한 실험결과는 수치해석 값과 잘 일치함을 확인하였다.

Multi-objective BESO topology optimization for stiffness and frequency of continuum structures

  • Teimouri, Mohsen;Asgari, Masoud
    • Structural Engineering and Mechanics
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    • 제72권2호
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    • pp.181-190
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    • 2019
  • Topology optimization of structures seeking the best distribution of mass in a design space to improve the structural performance and reduce the weight of a structure is one of the most comprehensive issues in the field of structural optimization. In addition to structures stiffness as the most common objective function, frequency optimization is of great importance in variety of applications too. In this paper, an efficient multi-objective Bi-directional Evolutionary Structural Optimization (BESO) method is developed for topology optimization of frequency and stiffness in continuum structures simultaneously. A software package including a Matlab code and Abaqus FE solver has been created for the numerical implementation of multi-objective BESO utilizing the weighted function method. At the same time, by considering the weaknesses of the optimized structure in single-objective optimizations for stiffness or frequency problems, slight modifications have been done on the numerical algorithm of developed multi-objective BESO in order to overcome challenges due to artificial localized modes, checker boarding and geometrical symmetry constraint during the progressive iterations of optimization. Numerical results show that the proposed Multiobjective BESO method is efficient and optimal solutions can be obtained for continuum structures based on an existent finite element model of the structures.

DVD 픽업보빈의 동특성 개선을 위한 병렬위상 최적설계법 응용 (Application of the Parallelized Topology Optimization for the Dynamic Characteristics Improvement of a DVD Pickup Bobbin)

  • 김태수;김재은;김윤영
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.365-367
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    • 2002
  • A parallelized topology optimization is applied to the design of a DVD-pickup bobbin, for which the design objective is to maximize the fundamental frequency within a given mass limit. Unlike the existing serial topology optimization, the present method can deal with a large number of design variables, and thus can yield practical and realistic results. The structural member-sizing filter is also employed to control the topological complexity of the optimized bobbin structure.

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