• Structural Engineering and Mechanics
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• v.61 no.4
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• pp.437-440
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• 2017

This study investigates the bending of an isotropic thin rectangular plate in finite deformation. Employing hyperelastic material of John's type, a non-classical model which generalizes the famous Kirchhoff's plate equation is obtained. Exact solution for deflection of the plate under sinusoidal loads is obtained. Finally, it is shown that the non-classical plate under consideration can be used as a replacement for Kirchhoff's plate on an elastic foundation.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.474-481
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• 1998

Metal bonded rubber spring is used in primary suspension component of the high speed train. The aim of this study is to establish a finite element analysis technique for the metal bonded rubber spring. Some theoretical analyses were performed on the hyperelastic behavior in rubber material and test are carried out to acquire the constants in strain energy function for it. Also, finite element analysis were executed to evaluate the design parameter and behavior of deformation and stress distribution using by the commercial finite element code.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.281-284
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• 2009

Flexible forming process for sheet metal using reconfigurable die is introduced based on numerical simulation. Numerical simulation of sheet metal forming process is carried out by using flexible dies model instead of conventional matched die set. Elastic cushion which has high resilience behavior from excessive deformation are inserted between forming punches and blank material for smoothing the forming surface which has discrete due to characteristics of the flexile die. As an elastic cushion, urethane pads are utilized using hyperelastic material model in the simulation. Formability in view of surface defect such as onset of dimple is compared with regard to various punch sizes. Consequently, it is confirmed that the flexible forming process for sheet material has appropriate capability and feasibility for manufacturing of smoothly curved surface instead of conventional die forming process.

• Smart Structures and Systems
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• v.6 no.8
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• pp.889-903
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• 2010

Idea of using piezoelectric materials with flexible structures made of rubber-like materials is quite novel. In this study a non-linear finite element model based on updated Lagrangian (UL) approach has been developed for dynamic response and its control of rubber-elastic material with surface-bonded PVDF patches/layers. A compressible stain energy density function has been used for the modeling of the rubber component. The results obtained are compared with available analytical solutions and other published results in some cases. Some results are reported as new results which will be useful for future references since the number of published results is not sufficient.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.3
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• pp.179-186
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• 2020

In this study, the wall stress and rupture risk for abdominal aortic aneurysms were calculated based on the age and geometry of the examined abdominal aortic aneurysms. The geometry of the abdominal aorta was simulated using computed tomography data from patients with abdominal aortic aneurysms. With regard to material properties, the Gasser-Ogden-Holzapfel model was applied to the analysis to simulate the anisotropic hyperelastic characteristics of the artery. In addition, each material parameter was estimated to consider the properties for age and for normal and aneurysm tissue. Moreover, the correlation between the diameter and angle of the aortic aneurysms was analyzed based on data from patients with abdominal aortic aneurysms, and series simulations were conducted. As a result, the rupture risk for the abdominal aortic aneurysms was evaluated based on the age and geometry of the aneurysm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.6
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• pp.848-859
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• 2004

Mechanical testing methods to determine the material constants for large deformation nonlinear finite element analysis were demonstrated for natural rubber. Uniaxial tension, uniaxial compression, equi-biaxial tension and pure shear tests of rubber specimens are performed to achieve the stress-strain curves. The stress-strain curves are obtained after between 5 and 10 cycles to consider the Mullins effect. Mooney and Ogden strain-energy density functions, which are typical form of the hyperelastic material, are determined and compared with each other. The material constants using only uniaxial tension data are about 20% higher than those obtained by any other test data set. The experimental equations of shear elastic modulus on the hardness and maximum strain are presented using multiple regression method. Large deformation finite element analysis of automotive transmission mount using different material constants is performed and the load-displacement curves are compared with experiments. The selection of material constant in large deformation finite element analysis depend on the strain level of component in service.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.425-430
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• 2003

The material properties of rubber was determined by the experiments of uniaxial tension, uniaxial compression, planer tension, equi-biaxial tension and volumetric compression. In compression test, it is difficult to obtain the pure state of compression stress and strain due to friction force between the specimen and compression platen. In this study, the stress and strain data from the equi-biaxial tension test were converted to compression stress and strain and compared to a perfect state of simple compression data when friction was zero. The compression test device with the tapered platen was proposed to overcome the effect of friction. It was turned out that the relationship of the stress and strain using the tapered platen was in close agreement with the pure compressive state.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.438-445
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• 2000

Tire performance is significantly influenced by the cord tension distribution, and which is governed by the tire shape. To increase the tire performance, it is very important for one to find the shape with the ideal distribution of tension. But it is not easy to find such an optimal tire shape. Therefore, in order for the successful tire-shape optimization, we need to investigate how the change of tire shape influences on the cord tension. In this paper, we intend to numerically analyse the relation between the carcass shape and the cord tension.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.193-202
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• 1998

본 논문에서는 비선형 고체역학 이론에 대하여 특히 시간에 무관한 변형을 하는 초탄성 및 탄소성고체물질의 비선형 변형이론에 대하여 철저한 분석을 수행하였다 특히 비선형 변형의 해석방범론에 대하여 특별한 관심을 가지고 분석하였다. 비선형 변형해석 방법론으로 널리 논의되고 있는 증분뉴튼랩슨 방법에 대하여 수정된 개념을 제시하여 비선형 변형 해석의 정 확성을 향상시켰다.

• Earthquakes and Structures
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• v.13 no.5
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• pp.465-471
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• 2017

This work derives a generalized time fractional differential equation governing wave propagation in a radially vibrating non-classical cylindrical medium. The cylinder is made of a transversely isotropic hyperelastic John's material which obeys frequency-dependent power law attenuation. Employing the definition of the conformable fractional derivative, the solution of the obtained generalized time fractional wave equation is expressed in terms of product of Bessel functions in spatial and temporal variables; and the resulting wave is characterized by the presence of peakons, the appearance of which fade in density as the order of fractional derivative approaches 2. It is obtained that the transversely isotropic structure of the material of the cylinder increases the wave speed and introduces an additional term in the wave equation. Further, it is observed that the law relating the non-zero components of the Cauchy stress tensor in the cylinder under consideration generalizes the hypothesis of plane strain in classical elasticity theory. This study reinforces the view that fractional derivative is suitable for modeling anomalous wave propagation in media.