• Title/Summary/Keyword: 유한요소해석

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유한요소해석에 의한 나노인덴테이션의 탄소성 변형에 관한 연구

  • 양현윤;조상봉;김지수;윤존도;김봉섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.10a
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    • pp.273-273
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    • 2003
  • 나노인덴테이션은 압자를 수 $\mu\textrm{N}$의 힘으로 시편에 압입을 시켜 재료의 경도나 탄성계수와 같은 기계적 특성을 평가하는 압입경도 시험법이다. 압입 변위를 나노미터범위로 조절할 수 있어 기존에 접근할 수 없었던 박막의 기계적 특성을 평가하는데 응용이 넓어지고 있다. 본 연구에서는 나노인덴테이션에서 제공되는 하중-변위곡선과 유한요소해석의 결과를 비교하여 유한요소해석의 신뢰성을 검증하고, 유한요소해석에서 여러 가지 재료의 특성에 따른 파일업과 싱크인 현상을 규명 하고자 한다.

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Evaluation on Flexural Performance of Precast Decks with Ribbed Joint by FEM (유한요소해석에 의한 요철형 이음단면을 갖는 프리캐스트 바닥판의 휨성능 평가)

  • Oh, Hyun-Chul;Chung, Chul-Hun;Kang, Myoung-Gu;Park, Se-Jin;Shin, Dong-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.1
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    • pp.85-94
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    • 2016
  • In this study, a non-linear FEM model is presented to predict the static flexural performance of precast bridge decks with ribbed joint and is verified with previous experiment results through comparison. The several theory of material properties were applied to each mechanical properties in FEM model and FEM model's input variables were determined through experiment result and parametric study. The FEM results showed good accuracy in predicting the structural performance of the specimens and FEM model's average error rate was 5%. Also, each specimen's cracking aspect and failure mode can be predicted through FEM's plastic strain distribution. Thus, this FEM model can be used effectively for predicting the ultimate behavior and parametric study to development of design formula for joint.

Inverse Estimation of Fatigue Life Parameters for Spring Design Optimization (스프링 최적설계를 위한 피로수명 파라미터의 역 추정)

  • Kim, Wan-Beom;An, Da-Wn;Choi, Joo-Ho
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.345-348
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    • 2011
  • 구조요소의 설계에서 유한요소해석은 매우 효과적인 방법이다. 이 방법은 시험 수행에 드는 시간과 비용을 줄여준다. 그러나 공정 과정과 환경에 의하여 생기는 입력 물성치들의 변화 때문에 우리는 유한요소해석의 결과를 전적으로 믿어서는 안 된다. 따라서 유한요소해석의 신뢰성을 증명하는 것은 매우 중요하다. 본 연구에서는 현장에 축적된 피로 수명 시험 데이터를 바탕으로 유한요소해석을 이용하여 피로수명 파라미터를 역 추정 하는 연구를 수행하였다. 베이지안 접근법을 이용하여 불확실성 피로 수명 파라미터의 사후분포를 구하였고, 마코프체인몬테카를로(Markov Chain Monte Carlo) 기법을 이용하여 역 추정된 파라미터의 샘플 데이터를 생성하였다. 얻어진 샘플 데이터를 기반으로 새로운 형상의 스프링에 대한 피로 수명을 예측한다. 신뢰성 기반 형상 최적화(RBDO)는 서스펜션 코일 스프링의 요구수명을 만족시키기 위하여 수행된다. 또한 크리깅 근사 모델은 유한요소해석의 연산 량 감소를 위해 이용한다.

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Analytical Study on Punching Shear of Reinforced Concrete Flat Plates (철근콘크리트 플랫 플레이트의 뚫림전단 거동에 관한 해석적 연구)

  • Kim, Min-Sook;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.409-415
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    • 2010
  • A finite element model for punching shear of flat plate structures is presented. A parametric study also has been conducted to verification of influence of several parameters in terms of the flexural reinforcement ratio, slab thickness. Reisnner-Mindlin assumptions are adopted to consider of shear deformation. Layered shell element is considered for the material non-linearities. The finite element model of this study was verified comparing with existing experimental results. The model is able to predict the capacity of the flat plate structures. The punching shear of flat plate structures varied depending on the flexural reinforcement ratio, slab thickness.

Determination of Mechanical Properties of Galvanized Steel Sheets Using Instrumented Indentation Technique and Finite Element Analysis (계장화 압입시험 및 유한요소해석을 이용한 아연도금강판의 기계적 물성 추정)

  • Jin, Ji-Won;Kwak, Sung-Jong;Kim, Tae-Seong;Noh, Ki-Han;Kang, Ki-Weon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.5
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    • pp.529-535
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    • 2012
  • This paper deals with the determination of mechanical properties of various galvanized steel sheets that are used for fabricating automobile bodies; the instrumented indentation technique and finite element analysis were used for the determination. First, tensile tests were conducted to obtain the true stress-true strain curves of galvanized steel sheets with various thicknesses. Load-deformation curves were then obtained by using the instrumented indentation testing machine, and they were compared with load-deformation curves obtained by finite element analysis. Further, true stress-true strain curves were obtained at the optimal observation point by finite element analysis.

Adaptive Mesh Refinement and Multigrid FEM by Error Estimation (오차추정에 의한 순응형요소분할과 다단계 유한요소해석)

  • Yang, P.D.C.;Hwang, M.Y.
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.1
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    • pp.90-97
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    • 1996
  • The optimal mesh refinement has a meaning that error of the every element is within an allowable level and in uniformly distributed. The adaptive mesh generation may be required to achieve the optimal mesh generation. For the purpose of optimal mesh generation, an error estimation and an adaptive mesh refinement are required. Using the adaptive mesh generation the second finite element analysis is performed with the result of the first analysis. In the process the error estimation is required. In this study the adaptive mesh generation program for triangular element is developed, and for a posteriori error estimation the stress projection approach is considered. It has been found the multigrid technique, where the error estimation and the mesh generation are combined in multi-step of analysis, may be used efficiently in the finite element analysis.

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Lumped Parameter Modelling and Analysis of Flat Coil Actuator with Shorted Turn (평판형 전자기 엑츄에이터의 집중매개변수 모델링 및 해석)

  • Hwang, Ki-Il;Kim, Jin-Ho;Lee, Jung-Hun
    • Journal of the Korean Magnetics Society
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    • v.20 no.4
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    • pp.149-152
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    • 2010
  • The flat coil actuator is widely used to make high precision products because it has no friction between the moving coil and the guide. Finite Element Method, a favored actuator design tool due to its high accuracy, was utilized to analyze the electromagnetic actuator, but it consumes a lot of time especially in computation iterations for optimization. Accordingly, the magnetic equivalent circuit analysis can be an alternative tool to FEM because of its computation iteration capability with fair accuracy. In this paper, lumped parameter model and the simulation results are presented. In addition, the result of lumped parameter analysis is compared with those obtained from finite element analysis for verification.

Study on Dowel-Bar Optimum Position of Jointed Concrete Pavement Using 3-D FEM Analysis (3차원 유한요소해석을 이용한 줄눈콘크리트 포장의 다웰바 최적배치에 대한 연구)

  • Chon, Beom Jun;Hong, Seong Jae;Lee, Seung Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.2D
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    • pp.135-141
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    • 2010
  • Dowel bar in the jointed concrete pavement has been designed and constructed by Foreign standard and experience in Korea. The behavior of dowel bar is explored based in analyze of 3-Dimension Finite Element Method. To evaluate behavior of dowel bar compared Timoshenko theory and 3-Dimensional Finite Element Method. Based on the 3-Dimension Finite Element Method analyze the dowel-bar optimum position that can reduce deflections of slabs by considering wheel path distributions was suggest in this study.

Non-linear Analysis of Full Scaled CFT Column to H-Beam Connections with T-Stiffeners (T 스티프너를 이용한 CFT기둥-H 형강보 실대형 접합부의 비선형 해석)

  • Lee, Seung Woo;Kim, Young Joo;Shin, Kyung Jae;Oh, Young Suk;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.14 no.6
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    • pp.835-843
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    • 2002
  • The goal of this paper is to understand the stress-transfer mechanism of concrete-filled tubular column to H-beam connection with external T stiffener through the elasto-plastic finite element method and to offer basic data for the design of T stiffener. For the accuracy, analysis results are compared with experimental results. It makes use of several stress and strain indices to understand the stress-transfer mechanism of connection. An alternative plan that decreases the stress concentration of beam flange to horizontal stiffener connection is proposed through the elasto-plastic finite element method.

Finite Element Analysis and Fatigue Life Evaluation of Automotive Rubber Insulator (자동차 방진 고무 부품의 유한요소해석 및 피로수명평가)

  • Kim, W.D.;Woo, C.S.;Han, S.W.
    • Elastomers and Composites
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    • v.33 no.3
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    • pp.168-176
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    • 1998
  • A strut rubber insulator is used in a suspension component of passenger cars. The uni-axial tension, compression, and the shear test were performed to acquire the constants of the strain energy functions which were Mooney-Rivlin model and Ogden model. The finite element analysis was executed to evaluate the behavior of deformation and stress distribution by using the commercial finite element code MARC ver K6.2. Also, the fatigue tests were carried out to obtain the fatigue life-load curve. The fatigue failure was initiated at the folded position of rubber, which was the same result predicted by the finite element analysis.

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