• 제목/요약/키워드: Structural Shape

검색결과 2,832건 처리시간 0.036초

확장 B-spline 기저 함수를 이용한 레벨셋 기반의 형상 최적 설계 (Level Set based Shape Optimization using Extended B-spline Bases)

  • 김민근;조선호
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 2008년도 정기 학술대회
    • /
    • pp.391-396
    • /
    • 2008
  • A level set based topological shape optimization using extended B-spline basis functions is developed for steady state heat conduction problems. The only inside of complicated domain is identified by the level set functions and taken into account in computation. The solution of Hamilton-Jacobi equation leads to an optimal shape according to the normal velocity field determined from the sensitivity analysis, minimizing a thermal compliance while satisfying a volume constraint. To obtain exact shape sensitivity, the precise normal and curvature of geometry need to be determined using the level set and B-spline basis functions. The nucleation of holes is possible whenever and wherever necessary during the optimization using a topological derivative concept.

  • PDF

선택적 요소방법을 이용한 형상 최적 설계 기법 개발 (Development of Shape Optimization Scheme Using Selective Element Method (Application to 2-D Problems))

  • 심진욱;신정규;박경진
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 춘계학술대회논문집C
    • /
    • pp.531-536
    • /
    • 2001
  • The structural shape optimization is a useful tool for engineers to determine the shape of a structure. During the optimization process, relocations of nodes happen successively. However, excessive movement of nodes often results in the mesh distortion and eventually deteriorates the accuracy of the optimum solution. To overcome this problem, an efficient method for the shape optimization has been developed. The method starts from the design domain which is large enough to hold the possible shape of the structure. The design domain has pre-defined uniform fine meshes. At every cycle, the method judges whether all the elements are inside of the structure or not. Elements inside of the structure are assigned with real material properties, however elements outside of the structure are assigned with nearly zero values. The performance of the method is evaluated through various examples.

  • PDF

박판구조물의 방사소음에 대한 형상 설계민감도 해석 (Shape Design Sensitivity Analysis For The Radiated Noise From Thin body)

  • 이제원;왕세명
    • 한국소음진동공학회:학술대회논문집
    • /
    • 한국소음진동공학회 2001년도 춘계학술대회논문집
    • /
    • pp.90-95
    • /
    • 2001
  • A continuum-based shape design sensitivity analysis (DSA) method is presented for the acoustic radiation from thin body. The normal derivative integral formulation is employed as an analysis formulation and differentiated directly by using material derivative to get the acoustic shape design sensitivity. In the acoustic sensitivity formulation, derivative coefficients of the structural normal velocities on the surface are required as the input. Thus, the shape design sensitivities of structural velocities on the surface with respect to the shape change are also calculated with continuum approach. A simple disk is considered as a numerical example to validate the accuracy and efficiency of the analytical shape design sensitivity equations derived in this research. This research should be very helpful to design an application involving thin body and to change its acoustic characteristics.

  • PDF

막 구조물의 측지선을 이용한 재단도 생성에 관한 연구 (A Study on Cutting Pattern Generation of Membrane Structures by Using Geometric Line)

  • 안상길;손수덕;김승덕
    • 한국공간구조학회:학술대회논문집
    • /
    • 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
    • /
    • pp.125-132
    • /
    • 2005
  • Membrane structures, a kind of lightweight soft structural system, are used for spatial structures. The material property of the membrane has strong axial stiffness, but little bending stiffness. The design procedure of membrane structures are needed to do shape finding, stress-deformation analysis and cutting pattern generation. In shape finding, membrane structures are unstable structures initially. These soft structures need to be introduced initial stresses because of its initial unstable state, and it happens large deformation phenomenon. And also there are highly varied in their size, curvature and material stiffness. So, the approximation inherent in cutting pattern generation methods is quite different. Therefore, in this study, to find the structural shape after large deformation caused by Initial stress, we need the shape analysis considering geometric nonlinear ten And the geodesic line on surface of initial equilibrium shape and the cutting pattern generation using the geodesic line is introduced.

  • PDF

막 구조물의 재단 패턴 결정에 관한 연구 (A Study on the Cutting Pattern Determination for Fabric Structures)

  • 최호;이장복;김재열;서삼열;권택진
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 1998년도 가을 학술발표회 논문집
    • /
    • pp.266-273
    • /
    • 1998
  • The object of this study is shape finding and cutting pattern generation of membrane structures under the following assumptions: (1) material is linearly elastic (2) stress state is plane stress. Cable and membrane structures should introduce the nonlinear analysis considering geometric nonlinearity because these structures deform largely under the external loads. The analysis procedure is consisted of three steps considering geometric nonlinearity unlike any other structures. First step is the shape finding analysis to determine the initial equilibrium shape. Second step is the stress-deformation analysis to investigate the behaviors of structures under various external loads. Once a satisfactory shape has been found, a cutting pattern based on the shape finding analysis may be generated from the view point of construction. In this paper, after shape finding analysis, cutting pattern determination procedure using weighted least-square minimization flattening method and some results are presented.

  • PDF

변위제약모드를 갖는 트러스구조물의 형태해석에 관한 연구 (A Study on the Shape Analysis of the Truss Structures under the Prescribed Displacement Mode)

  • 문창훈;김진기;최옥훈;한상을
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 1997년도 가을 학술발표회 논문집
    • /
    • pp.262-269
    • /
    • 1997
  • The purpose of this study is to survey the shape finding of the plane truss structures under the prescribed displacement mode by the shape analysis. The shape analysis is peformed by the existence condition of a solution and Moore-Penrose generalized inverse matrix, and the prescribed displacement mode is the homologous deformation of structures. The shape analysis of structures is a kind of inverse problem and become the problem of a nonlinear equation. Newton-Raphson method is used to improve the accuracy of approximated solution. To prove the accuracy and the effectiveness of this method, four different shape examples are analyzed.

  • PDF

Geodesic shape finding of membrane structure with geodesic string by the dynamic relaxation method

  • Lee, K.S.;Han, S.E.
    • Structural Engineering and Mechanics
    • /
    • 제39권1호
    • /
    • pp.93-113
    • /
    • 2011
  • The explicit nonlinear dynamic relaxation method (DRM) is applied to the nonlinear geodesic shape finding analysis by introducing fictional tensioned 'strings' along the desired seams with a three or four-node membrane element. A number of results from the numerical example for the nonlinear geodesic shape finding and patterning analysis are obtained by the proposed method to demonstrate the accuracy and efficiency of the developed method. Therefore, the proposed geodesic shape finding algorithm may improve the applicability of a four-node membrane element to membrane structural engineering and design analysis simultaneously for the shape finding, stress, and patterning analysis.

복합형상 부품 가공용 라인센터의 경량화를 위한 형상 최적화에 관한 연구 (Shape Optimization for Lightweight of the Line Center for Processing Complex Shape Parts)

  • 박도현;정호인;김상원;이춘만
    • 한국기계가공학회지
    • /
    • 제20권8호
    • /
    • pp.86-92
    • /
    • 2021
  • As interest and demand for high value-added industries, including the global automobile and aerospace industries, have increased recently, demand for line centers with excellent performance that can respond to the production system for producing high value-added products is also rapidly increasing. A line center improves productivity based on the installed area using a multi-spindle compared to a conventional machining center. However, as the number of spindles increases, the weight increases and results in structural problems owing to the heat and vibration generated by each spindle. Therefore, it is necessary to improve machining precision through the structural improvement of the line center. This study presents research on the stabilization design of the line center through structural stability analysis through structural analysis to develop a compact multi-axis line center. An optimization model of the line center has been proposed to improve the processing precision and increase the rigidity by performing weight reduction based on the structural analysis results.

메타모델을 이용한 크레인 부품 조의 구조설계 (Structural Design of a Container Crane Part-Jaw, Using Metamodels)

  • 송병철;방일권;한동섭;한근조;이권희
    • 한국기계가공학회지
    • /
    • 제7권3호
    • /
    • pp.17-24
    • /
    • 2008
  • Rail clamps are mechanical components installed to fix the container crane to its lower members against wind blast or slip. According to rail clamps should be designed to survive harsh wind loading conditions. In this study, a jaw structure, which is a part of a wedge-typed rail clamp, is optimized with respect to its strength under a severe wind loading condition. According to the classification of structural optimization, the structural optimization of a jaw is included in the category of shape optimization. Conventional structural optimization methods have difficulties in defining complex shape design variables and preventing mesh distortions. To overcome the difficulties, the metamodel using Kriging interpolation method is introduced to replace the true response by an approximate one. This research presents the shape optimization of a jaw using iterative Kriging interpolation models and a simulated annealing algorithm. The new Kriging models are iteratively constructed by refining the former Kriging models. This process is continued until the convergence criteria are satisfied. The optimum results obtained by the suggested method are compared with those obtained by the DOE (design of experiments) and VT (variation technology) methods built in ANSYS WORKBENCH.

  • PDF

Mode shape expansion with consideration of analytical modelling errors and modal measurement uncertainty

  • Chen, Hua-Peng;Tee, Kong Fah;Ni, Yi-Qing
    • Smart Structures and Systems
    • /
    • 제10권4_5호
    • /
    • pp.485-499
    • /
    • 2012
  • Mode shape expansion is useful in structural dynamic studies such as vibration based structural health monitoring; however most existing expansion methods can not consider the modelling errors in the finite element model and the measurement uncertainty in the modal properties identified from vibration data. This paper presents a reliable approach for expanding mode shapes with consideration of both the errors in analytical model and noise in measured modal data. The proposed approach takes the perturbed force as an unknown vector that contains the discrepancies in structural parameters between the analytical model and tested structure. A regularisation algorithm based on the Tikhonov solution incorporating the L-curve criterion is adopted to reduce the influence of measurement uncertainties and to produce smooth and optimised expansion estimates in the least squares sense. The Canton Tower benchmark problem established by the Hong Kong Polytechnic University is then utilised to demonstrate the applicability of the proposed expansion approach to the actual structure. The results from the benchmark problem studies show that the proposed approach can provide reliable predictions of mode shape expansion using only limited information on the operational modal data identified from the recorded ambient vibration measurements.