• 제목/요약/키워드: Hyper-elastic

검색결과 62건 처리시간 0.033초

초탄성고무 물성평가용 미소압입시험기의 소프트웨어 및 하드웨어 개발 (Software and Hardware Development of Micro-indenter for Material Property Evaluation of Hyper-Elastic Rubber)

  • 이형일;김동욱;이진행;남승훈
    • 대한기계학회논문집A
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    • 제28권6호
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    • pp.816-825
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    • 2004
  • In this work, effects of hyper-elastic rubber material properties on the indentation load-deflection curve and subindenter deformation are examined via finite element (FE) analyses. An optimal location for data analysis is selected, which features maximum strain energy density and negligible frictional effect. We then contrive two normalized functions, which map an indentation load vs. deflection curve into a strain energy density vs. first invariant curve. From the strain energy density vs. first invariant curve, we can extract the rubber material properties. This new spherical indentation approach produces the rubber material properties in a manner more effective than the common uniaxial tensile/com-pression tests. The indentation approach successfully measures the rubber material properties and the corresponding nominal stress-strain curve with an average error less than 3%.

신장률 변화에 따른 초탄성 재료의 비선형 재료모델 비교 연구 (Comparative Study on the Nonlinear Material Model of HyperElastic Material Due to Variations in the Stretch Ratio)

  • 이강수;기민석;박병재
    • 한국해양공학회지
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    • 제32권4호
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    • pp.253-260
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    • 2018
  • Recently, the application of non-steel materials in ships and offshore plants is increasing because of the development of various nonlinear materials and the improvement of performance. Especially, hyper-elastic materials, which have a nonlinear stress-strain relationship, are used mainly in marine plant structures or ships where impact relaxation, vibration suppression, and elasticity are required, while elasticity must be maintained, even under high strain conditions. In order to simulate and evaluate the behavior of the hyperelastic material, it is very important to select an appropriate material model according to the strain of the material. This study focused on the selection of material models for hyperelastic materials, such as rubber used in the marine and offshore fields. Tension and compression tests and finite element simulations were conducted to compare the accuracy of the nonlinear material models due to variations in the stretch ratio of hyper-elastic material. Material coefficients of nonlinear material models are determined based on the curve fitting of experimental data. The results of this study can be used to improve the reliability of nonlinear material models according to stretch ratio variation.

공기식 브레이크 밸브의 요소설계 (Simulation Study on the Design of Air Brake Valve for Automobile Applications)

  • 이동우;전민승;송정일
    • 한국정밀공학회지
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    • 제34권2호
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    • pp.145-150
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    • 2017
  • Air brake valves are widely used in automotive braking systems and the Korean automobile industry depends on importing them. Therefore, we should develop the technical expertise for their domestic production. In this study, air brake valves were analyzed that can be used in a variety of automobiles. Computational fluid dynamics analysis, static structural analysis, and hyper-elastic analysis were carried out. Before production of an air brake valve system, the performance of different parts has to be evaluated, for instance by using finite element analysis. The structural stability of the product can be determined using static dynamics. The compression behavior of the O-ring is predictable by nonlinear hyper elastic analysis, although errors are possible due to one-way loading. This simulation study can both save time and reduce costs compared to the development of experimental prototypes.

초탄성 고무 물성평가를 위한 구형 압입시험의 수치접근법 (Numerical Approach Technique of Spherical Indentation for Material Property Evaluation of Hyper-elastic Rubber)

  • 이형일;이진행;김동욱
    • Elastomers and Composites
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    • 제39권1호
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    • pp.23-35
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    • 2004
  • 본 연구에서는 먼저 유한요소해석을 통해 주요 물성계수들이 압입시 하중-변위 곡선형상에 미치는 영향을 분석하였다. 또한 유한요소 압입해석을 통해 마찰계수의 영향으로 하중-변위 곡선, 시편하부의 단위부피당 변형에너지 및 변형률 주불변량이 바뀌지 않는 최적 압입깊이와 시편하부지점을 선정하였다. 이러한 관찰을 통해 하나의 요소에서 얻어지는 단위부피당 변형 에너지와 변형률 주불변량을 하중-변위 데이터와 모사 시킬 수 있는 무차원 함수를 얻을 수 있었으며, 이 과정에서 예측된 물성계수를 바탕으로 공칭응력-공칭변형률 곡선을 얻을 수 있었다.

초탄성 재료의 변형률에너지함수를 이용한 LRB받침의 유한요소해석 (Finite Element Analysis of Lead Rubber Bearing by Using Strain Energy Function of Hyper-Elastic Material)

  • 조성국;박웅기;윤성민
    • 대한토목학회논문집
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    • 제36권3호
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    • pp.361-374
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    • 2016
  • 이 연구는 대표적인 면진장치인 납고무베어링(LRB)의 유한요소모델의 신뢰성을 향상시키기 위하여 주재료인 고무의 재료특성에 대하여 연구하였다. 고무는 일반적인 탄성재료와는 달리 대변형, 비선형특성을 가지는 초탄성 재료이다. 본 연구에서는 고무를 초탄성 재료로 가정하고 그의 재료특성을 변형률에너지함수로 표현하여 LRB의 유한요소모델을 개발하였다. 연구를 위하여 여러 변형률에너지함수 중 몇 가지를 선별하고 이를 이용하여 고무의 재료특성을 예측하였다. 변형률에너지함수를 이용하여 결정된 고무의 재료특성과 표준적인 납의 재료특성을 이용하여 LRB의 유한요소모델을 개발하고, 수평방향과 수직방향의 힘-변위 관계를 해석하였다. LRB의 유한요소모델을 통하여 해석으로 예측한 수평과 수직방향 강성을 실험결과와 비교함으로써 개발된 유한요소모델의 적합성을 검증하였다.

고무패드 변형의 3차원 유한요소해석 (Three-dimensional Finite Element Analysis of Rubber Pad Deformation)

  • 신수정;이태수;오수익
    • 대한기계학회논문집A
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    • 제22권1호
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    • pp.111-120
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    • 1998
  • This paper is the first one of two-parted research efforts focusing on the modeling of rubber pad forming process. The rubber pad, driven by the pressurized fluid during the forming process, pushes the sheet metal to solid tool half and forms a part to final shape. In this part of the paper, a numerical procedure for the FE analysis of the rubber pad deformation is presented. The developed three-dimensional FE model is based on the total Lagrangian description of rubber maerial characterized by nearly incompressible hyper-elastic behavior under a large deformation assumption. Validity of the model as well as effects of different algorithms corresponding to incompresibility constraints and time integration methods on numerical solution responses are also demonstrated.

SINGULAR PERIODIC SOLUTIONS OF A CLASS OF ELASTODYNAMICS EQUATIONS

  • Yuan, Xuegang;Zhang, Yabo
    • Journal of applied mathematics & informatics
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    • 제27권3_4호
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    • pp.501-515
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    • 2009
  • A second order nonlinear ordinary differential equation is obtained by solving the initial-boundary value problem of a class of elas-todynamics equations, which models the radially symmetric motion of a incompressible hyper-elastic solid sphere under a suddenly applied surface tensile load. Some new conclusions are presented. All existence conditions of nonzero solutions of the ordinary differential equation, which describes cavity formation and motion in the interior of the sphere, are presented. It is proved that the differential equation has singular periodic solutions only when the surface tensile load exceeds a critical value, in this case, a cavity would form in the interior of the sphere and the motion of the cavity with time would present a class of singular periodic oscillations, otherwise, the sphere remains a solid one. To better understand the results obtained in this paper, the modified Varga material is considered simultaneously as an example, and numerical simulations are given.

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나노 인덴테이션 공정의 유한요소해석 및 실험적 검증 (Finite Element Analysis of Nanoindentation Process and its Experimental Verification)

  • 이정우;윤성원;강충길
    • 소성∙가공
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    • 제12권4호
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    • pp.382-387
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    • 2003
  • In this study, to achieve the optimal conditions for mechanical hyper-fine pattern fabrication process, deformation behaviors of the materials during indentation were studied with numerical method by ABAQUS S/W. Brittle materials (Si, Pyrex glass 7740) were used as specimens, and forming conditions to reduce the elastic recovery and pile-up were proposed. The indenter was modeled a rigid surface. Minimum mesh sizes of specimens are 1-10nm. Comparisons between the experimental data and numerical result demonstrated that the finite element approach is capable of reproducing the loading-unloading behavior of a nanoindentation test.

고무 재질 탄성 마운트의 비선형 대변형 거동 해석 (Non-linear Large Deformation Analysis of Elastic Rubber Mount)

  • 노인식;김종만;곽정석
    • 대한조선학회논문집
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    • 제45권2호
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    • pp.186-191
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    • 2008
  • A lot of equipments installed in ships must be isolated for relaxing the shock, vibration and noise using the elastic mounts. Most of the elastic mounts are made of the rubber, however it is not easy to design the effective rubber mount. Because, in general, the rubber has a non-linear constitutive characteristics especially for a large deformation. So, there are many difficulties to estimate the accurate structural response of rubber which is the basis of the shape design of the mounts. In this study, the detailed non-linear viscoelastic large deformation finite element analysis method was dealt with. And to verify validity of the present analysis scheme, the results were compared with experiments.