• Title/Summary/Keyword: Hyper-elastic

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

  • Lee, Hyung-Yil;Kim, Dong-Wook;Lee, Jin-Haeng;Nahm, Seung-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.6
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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%.

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

  • Lee, Kangsu;Ki, Minsuk;Park, Byoungjae
    • Journal of Ocean Engineering and Technology
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    • v.32 no.4
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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.

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

  • Lee, Dong Woo;Jun, Min-Seung;Song, Jung Il
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.2
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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.

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

  • Lee, Hyung-Yil;Lee, Jin-Haeng;Kim, Dong-Wook
    • Elastomers and Composites
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    • v.39 no.1
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    • pp.23-35
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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 first examined via finite element (FE) analyses. An optimal data acquisition spot 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/compression tests. The indentation approach successfully measures the rubber material properties and the corresponding nominal stress-strain curve.

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

  • Cho, Sung Gook;Park, Woong Ki;Yun, Sung Min
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.36 no.3
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    • pp.361-374
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    • 2016
  • The material property of the rubber has been studied in order to improve the reliability of the finite element model of a lead rubber bearing (LRB) which is a typical base isolator. Rubber exhibits elastic behaviour even within the large strain range, unlike the general structural material, and has a hyper-elastic characteristics that shows non-linear relationship between load and deformation. This study represents the mechanical characteristics of the rubber by strain energy function in order to develop a finite element (FE) model of LRB. For the study, several strain energy functions were selected and mechanical properties of the rubber were estimated with the energy functions. A finite element model of LRB has been developed by using material properties of rubber and lead which were identified by stress tests. This study estimated the horizontal and vertical force-displacement relationship with the FE model. The adequacy of the FE model was validated by comparing the analytical results with the experimental data.

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

  • Shin, S.J;Lee, T.S;Oh, S.I
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.1
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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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    • v.27 no.3_4
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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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Finite Element Analysis of Nanoindentation Process and its Experimental Verification (나노 인덴테이션 공정의 유한요소해석 및 실험적 검증)

  • 이정우;윤성원;강충길
    • Transactions of Materials Processing
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    • v.12 no.4
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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.

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

  • Nho, In-Sik;Kim, Jong-Man;Kwak, Jeong-Seok
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.2
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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.