• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.491-494
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• 2002

To assess the electrostatic interaction of surfaces at the triple contact line, the electrostatic field is analyzed by using the finite element method. The Helmholtz free energy is used as a functional which should be minimized under an equilibrium condition. The numerical results are compared with the nonlinear analytical solution for a two-dimensional charged interface and linear solution for a wedge shaped geometry, which shows fairly good agreement. The method is applied to the analysis of electrostatic influence on the contact angle on a charged substrate. The excess free energy found to increase drastically as the contact angle approaches to zero. This excess free energy Plays an opposite role to the Primary electrocapillary effect, as the contact angle gets smaller. This enables an alternative explanation for the contact-angle saturation phenomenon occurring in electrical control of surface tension and contact angle.

• 한국전산구조공학회논문집
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• 제25권2호
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• pp.163-173
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• 2012

이 연구에서는 프리스트레싱용 고강도 강연선의 정착장치 중 강연선을 직접 정착하는 앵커헤드(anchor head)에 대해 거동특성을 분석하고, 앵커헤드의 제원을 결정하는 단계에 있어서 해석적 검토에 요구되는 프로세스에 대해 정립하였다. 앵커헤드는 쐐기와의 접촉(contact)을 통해 강연선으로부터의 힘이 전달되고 거동변화에 따라 접촉상태 또한 변하게 된다. 이를 고려한 상세 거동분석을 위해 쐐기와 헤드 사이의 접촉(contact)조건을 설정하였으며, 앵커헤드의 비선형 재료모델을 적용하여 기하 및 재료 비선형성을 고려한 구조해석을 수행하였다. 해석결과로부터 다음의 결과를 얻을 수 있었다. 앵커헤드의 거동은 앵커헤드와 쐐기 간의 상호거동에 크게 영향을 받기 때문에 초기 설계단계부터 상대 영향을 고려해야 한다. 쐐기홀(wedge hole)의 배치는 층배열(layered) 보다는 원형배열(circular)이 보다 응력분배에 효과적이고, 쐐기홀의 간격을 증가시키고 헤드 하면 구멍의 크기를 줄여 구멍사이 강재의 두께를 다소 늘이는 것이 구조거동에 효과적이다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1487-1488
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• 2010

• 대한기계학회논문집A
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• 제28권6호
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• pp.747-754
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• 2004

The nonlinear finite element analysis for deformation characteristics of a power steering hose during the swaging process is performed in order to investigate the stress and the strain levels of the hose components. Power steering hose consists of components such as rubber hose, nylon, nipple and sleeve. Moreover, the numerical analysis requires the consideration of material, geometry and boundary nonlinearities. To evaluate the rubber hose strength, the measured stresses and strains are compared with tension and compression test data. Contact force is also a principal factor to examine whether rubber hose is break away from sleeve and nipple or not.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1576-1580
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• 2007

Typical lip seals are widely used as sealing mechanism of rotary and reciprocating shaft. Double lip seal has comparatively high stiffness and dynamic radial eccentricity. Usually material of these seals is made of elastomer and nonlinear finite element analysis is required to analyze behaviour of this material because Young's modulus is varied with working load. In this paper, MSC MARC/MENTAT is used for nonlinear analysis of double lip seal with pressure variation and interference. The contact normal force of double lip seal between lip and shaft is analyzed to reduce power loss when shaft rotates.

• 한국소음진동공학회논문집
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• 제21권3호
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• pp.271-279
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• 2011

In this study, the dynamic analysis of a beam is analyzed by using the finite element method when the beam has moving mass and axial load. To consider the contact force between the moving mass and beam, coupled nonlinear equations of contact dynamics are derived, and then the weak form for the finite element method is established. The finite element computer programs based on the Lagrange multiplier method are developed to compute the contact force. Furthermore, a variety of simulations are performed for various design parameters such as moving mass velocity, compressive axial load and tension load. Finally, relations between the dynamic response and contact force are also discussed.

• Steel and Composite Structures
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• 제27권3호
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• pp.273-283
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• 2018

Nonlinear low velocity impact response of sandwich beam with laminated composite face sheets and soft core is studied based on Extended High Order Sandwich Panel Theory (EHSAPT). The face sheets follow the Third order shear deformation beam theory (TSDT) that has hitherto not reported in conventional EHSAPT. Besides, the two dimensional elasticity is used for the core. The nonlinear Von Karman type relations for strains of face sheets and the core are adopted. Contact force between the impactor and the beam is obtained using the modified Hertz law. The field equations are derived via the Ritz based applied to the total energy of the system. The solution is obtained in the time domain by implementing the well-known Runge-Kutta method. The effects of boundary conditions, core-to-face sheet thickness ratio, initial velocity of the impactor, the impactor mass and position of the impactor are studied in detail. It is found that each of these parameters have significant effect on the impact characteristics which should be considered. Finally, some low velocity impact tests have been carried out by Drop Hammer Testing Machine. The contact force histories predicted by EHSAPT are in good agreement with that obtained by experimental results.

• 한국자동차공학회논문집
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• 제13권4호
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• pp.1-7
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• 2005

In vehicle door system, weatherstrip seals protect passengers form noise, dust, rain and wind out of the vehicle. The higher efficient a weatherstrip is, the more durable it is in contact between the door and body frame. In this study, nonlinear finite element(FE) analysis is performed to obtain cauchy-stresses, displacements and reaction forces of the weatherstrip. Mechanical properties of the weatherstrip is obtained by uniaxial tension test. The MARC which is a commercial software for the nonlinear analysis of a flexible FE model is used. Twenty-one cases of the FE model are developed by using Ogden-foam formulation. In the results of nonlinear FE analysis, the most valuable deformation of the weatherstrip occurred when displacement control value reaches 7.2mm. Severe deformation is observed as the displacement control value become more increased. When the weatherstrip is designed, it would be considered that the displacement value of the weatherstrip has to be less than 7.2mm.

• Journal of applied mathematics & informatics
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• 제42권2호
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• pp.305-320
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• 2024

We consider a mathematical model which describes the quasistatic contact of electro-viscoelastic rod with an obstacle. We use a modified Kelvin-Voigt viscoelastic constitutive law in which the elasticity operator is nonlinear and locally Lipschitz continuous, taking into account the piezoelectric effect of the material. We model the contact with a general damped response condition. We establish a local existence and uniqueness result of the solution by using arguments of time-dependent nonlinear equations and Schauder's fixed-point theorem and obtain a global existence for small enough data.

• 대한기계학회논문집A
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• 제29권7호
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• pp.955-963
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• 2005

This research investigates dynamic characteristics of a linear motion (LM) guide through a experimental result and theoretical analysis. The stiffness in the LM guide is determined by the preloading due to the minus clearance between the ball bearing and the contact surface and it can be derived by Hertzian contact theory and the nonlinear motion of equation. The vibration analysis is performed using Lagrange equations and its result agrees with the experiment result. Using the sensitivity analysis on design parameters such as the contact angles of ball bearings and the eccentricity of mass center, the variation of the natural frequencies can be predicted.