• Title/Summary/Keyword: Substructuring method

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Finite Element Stress Analysis of Coil Springs using a Multi-level Substructuring Method II : Validation and Analysis (다단계 부분구조법을 이용한 코일스프링의 유한요소 응력해석 II : 검증 및 해석)

  • Kim, Jin-Young;Huh, Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.3
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    • pp.151-162
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    • 2000
  • This study is concerned with computerized multi-level substructuring methods and stress analysis of coil springs. The purpose of substructuring methods is to reduce computing time and capacity of computer memory by multiple level reduction of the degrees of freedom in large size problems that are modeled by three dimensional continuum finite elements. In this paper, the spring super element developed is investigated with tension, torsion, and bending of a cylindrical bar in order to verify its accuracy and efficiency for the multi-level substructuring method. And then the algorithm is applied to finite element analysis of coil springs. The result demonstrates the validity of the multi-level substructuring method and the efficiency in computing time and memory by providing good computational results in coil spring analysis.

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SUBSTRUCTURING ALGORITHM FOR STRUCTURAL OPTIMIZATION USING THE FORCE METHOD

  • JANG, HO-JONG
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.2 no.2
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    • pp.41-47
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    • 1998
  • We consider some numerical solution methods for equality-constrained quadratic problems in the context of structural analysis. Sparse orthogonal schemes for linear least squares problem are adapted to handle the solution step of the force method. We also examine these schemes with substructuring concepts.

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Dynamic Characteristics Identification of Cylindrical Structure Using Dynamic Substructuring Method (Dynamic Substructuring 기법을 이용한 원통형 구조물의 동특성 확인)

  • Choi, Youngin;Park, No-Cheol;Lee, Sang-Jeong;Park, Young-Pil;Kim, Jinsung;Park, Chanil;Roh, Woo-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.106-109
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    • 2014
  • In order to obtain dynamic behaviors of complex structures, it demands large amounts computational cost and time to perform the numerical analysis. The model reduction method helps these problems by dividing the full model into primary and unnecessary parts. In this research, we perform the modal analysis using the dynamic substructuring method, which is one of the model reduction methods, in order to obtain the dynamic characteristics of the cylindrical structures efficiently. To select the master degrees of freedom (dofs), we consider the mode shapes of the cylindrical structures. And then, we identify the validity of the dynamic substructuring method by applying the method to the simple cylinder and core support barrel (CSB) which is one of the reactor internals with the cylindrical shape. The results demonstrate that the dynamic characteristics from the dynamic substructuring method are well matched with the original method.

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Domain Decomposition using Substructuring Method and Parallel Comptation of the Rigid-Plastic Finite Element Analysis (부구조법에 의한 영역 분할 및 강소성 유한요소해석의 병렬 계산)

  • Park, Keun;Yang, Dong-Yol
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.03a
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    • pp.246-249
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    • 1998
  • In the present study, domain decomposition using the substructuring method is developed for the computational efficiency of the finite element analysis of metal forming processes. In order to avoid calculation of an inverse matrix during the substructuring procedure, the modified Cholesky decomposition method is implemented. As obtaining the data independence by the substructuring method, the program is easily parallelized using the Parallel Virtual Machine(PVM) library on a workstation cluster connected on networks. A numerical example for a simple upsetting is calculated and the speed-up ratio with respect to various domain decompositions and number of processors. Comparing the results, it is concluded that the improvement of performance is obtained through the proposed method.

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Domain Decomposition using Substructuring Method and Parallel Computation of the Rigid-Plastic Finite Element Analysis (부구조법에 의한 영역 분할 및 강소성 유한요소해석의 병렬 계산)

  • Park, Keun;Yang, Dong-Yol
    • Transactions of Materials Processing
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    • v.7 no.5
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    • pp.474-480
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    • 1998
  • In the present study a domain decomposition scheme using the substructuring method is developed for the computational efficiency of the finite element analysis of metal forming processes. in order to avoid calculation of an inverse matrix during the substructuring procedure, the modified Cholesky decomposition method is implemented. As obtaining the data independence by the substructuring method the program is easily paralleized using the Parallel Virtual machine(PVM) library on a work-station cluster connected on networks. A numerical example for a simple upsetting is calculated and the speed-up ratio with respect to various number of subdomains and number of processors. The efficiency of the parallel computation is discussed by comparing the results.

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Dynamic Stress Analysis of Structural Connection using FRF-based Substructuring Method (구조물의 연결부에서 전달함수합성법을 이용한 동응력 해석)

  • 공태식;김찬묵;이두호;서세영
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1195-1201
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    • 2002
  • Researches on the FRF-based substructuring method have been mainly focused on vibratory response analysis. Present study Is concerned about the application of the method to the dynamic stress analysis of a air-conditioner compressor mounting bracket in a passenger car. This is performed by using reaction forces that can be obtained by the FRF-based substructuring method. The air-conditioner system, composed of a compressor and bracket, Is analyzed by using the FRF-based substructuring method. The experimental and numerical FRFs are combined to calculate the system responses and reaction forces at the connection point. The dynamic reaction forces plugged into the bracket FE model to compute the stresses of the bracket Dynamic strains by the present method are compared with those from strain-gage test for bracket system on shaker. The comparison shows possibility of practical usage of the method for the real problem

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NUMERICAL SOLUTION OF EQUILIBRIUM EQUATIONS

  • Jang, Ho-Jong
    • Communications of the Korean Mathematical Society
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    • v.15 no.1
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    • pp.133-142
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    • 2000
  • We consider some numerical solution methods for equilibrium equations Af + E$^{T}$ λ = r, Ef = s. Algebraic problems of this form evolve from many applications such as structural optimization, fluid flow, and circuits. An important approach, called the force method, to the solution to such problems involves dimension reduction nullspace computation for E. The purpose of this paper is to investigate the substructuring method for the solution step of the force method in the context of the incompressible fluid flow. We also suggests some iterative methods based upon substructuring scheme..

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Optimization of an Engine Mount System of passenger Car using the Multi-domain FRF-based Substructuring Method (다중 전달함수합성법을 이용한 승용차 엔진마운트 시스템의 최적설계)

  • 이두호;황우석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.399-404
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    • 2002
  • Analyzing acoustic-structural systems such as automobiles and aircraft the FRF-based substructuring method is one of the most powerful tools. In this paper, an optimization procedure far the engine mount system of passenger car has been presented using the design sensitivity analysis based on the multi-domain FRF-based substructuring formulation. The proposed method is applied to an optimization problem of the engine mount system, of which objective is to minimize the interior sound over the concerned rpm range. The design variables selected are the stiffnesses of the engine mounts and bushes. Plugging the gradient information calculated by the proposed method into nonlinear optimization software, we can obtain the optimal stiffnesses of the engine mounts and bushings through design iterations. The optimized interior noise in the passenger car shows that the proposed method is very useful in the realistic situation.

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Efficient Dynamic Response Analysis Using Substructuring Reduction Method for Discrete Linear System with Proportional and Nonproportional Damping

  • Choi, Dong-Soo;Cho, Maeng-Hyo;Kim, Hyun-Gi
    • International Journal of Aeronautical and Space Sciences
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    • v.9 no.1
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    • pp.85-99
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    • 2008
  • The dynamic response analysis for large structures using finite element method requires a large amount of computational resources. This paper presents an efficient vibration analysis procedure by combining node-based substructuring reduction method with a response analysis scheme for structures with undamped, proportional or nonproportional damping. The iterative form of substructuring reduction scheme is derived to reduce the full eigenproblem and to calculate the dynamic responses. In calculating the time response, direct integration scheme is used because it can be applied directly to the reduced model. Especially for the non proportional damping matrix, the transformation matrices defined in the displacement space are used to reduce the system. The efficiency and the effectiveness of the present method are demonstrated through the numerical examples.

A Study on the Bending Analysis of Rectangular Plates by Substructuring Technique (분할구조기법을 이용한 장방형판의 휨해석에 관한 연구)

  • 오숙경;김성용;김일중;이용수
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.10a
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    • pp.65-72
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    • 1997
  • This study is the bending analysis of rectangular plates with 4-sides simply supported by Finite Element Method using substructuring technique. In finite element method, as the more number of finite element, the more dimension of matrix, it is difficult to obtain accuracy solution. In this paper substructuring technique is applied to finite element method in order to reduce the dimension of matrix according to the number of finite element mesh. To validate finite element method using substructuring technique, deflections and moments of rectangular plates by that method is compared with those of references. Considering the symmetry of the plate and load, one fourth of plate is analyzed. Operating time and the error of solutions according to the number of finite element mesh and substructure are compared with each other.

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