• Title/Summary/Keyword: Elastic Contact Problem

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On the receding contact between a two-layer inhomogeneous laminate and a half-plane

  • Liu, Zhixin;Yan, Jie;Mi, Changwen
    • Structural Engineering and Mechanics
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    • v.66 no.3
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    • pp.329-341
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    • 2018
  • This paper considers the smooth receding contact problem between a homogeneous half-plane and a composite laminate composed of an inhomogeneously coated elastic layer. The inhomogeneity of the elastic modulus of the coating is approximated by an exponential function along the thickness dimension. The three-component structure is pressed together by either a concentrated force or uniform pressures applied at the top surface of the composite laminate. Both semianalytical and finite element analysis are performed to solve for the extent of contact and the contact pressure. In the semianalytical formulation, Fourier integral transformation of governing equations and boundary conditions leads to a singular integral equation of Cauchy-type, which can be numerically integrated by Gauss-Chebyshev quadrature to a desired degree of accuracy. In the finite element modeling, the functionally graded coating is divided into homogeneous sublayers and the shear modulus of each sublayer is assigned at its lower boundary following the predefined exponential variation. In postprocessing, the stresses of any node belonging to sublayer interfaces are averaged over its surrounding elements. The results obtained from the semianalytical analysis are successfully validated against literature results and those of the finite element modeling. Extensive parametric studies suggest the practicability of optimizing the receding contact peak stress and the extent of contact in multilayered structures by the introduction of functionally graded coatings.

The wheel wear prediction of a Korea High Speed Train using a FE-analysis (유한요소해석을 이용한 한국형 고속철도 차량의 차륜 마모 예측)

  • Choi Jeong Heum;Han Dong-Chul;Kim Ki-Hwan
    • Proceedings of the KSR Conference
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    • 2005.05a
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    • pp.409-414
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    • 2005
  • It is difficult to apply the Hertz theory to the wheel-rail contact problem which has the complicated geometric form and plastic deformation. Therefore, we perform the elastic-plastic FE analysis and compare the results with those of Hertz theory. Kalker's simplified theory of rolling contact is used to discretize the contact patches and calculate local traction and slip. The wear volumes are calculated using Archard wear equation.

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Elastohydrodynamic Lubrication on the Vane Tip of Vane Pump (베인 선단부의 탄성유체윤활)

  • 정석훈;정재연
    • Tribology and Lubricants
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    • v.10 no.3
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    • pp.54-61
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    • 1994
  • The regimes of elastohydrodynamic lubrication at the points where line contacts occur between the vane tip and camring in an oil hydraulic vane pump is studied. A study of the contact conditions in vane pump provided most of the early interest in the possibility of fluid film lubrication in highly loaded contacts. The variation of viscosity with pressure and the elastic deformation associated with the high pressures generated in the contact region are the major causes of the complexity attributed to lubrication behavior. Therefore a numerical solutions to the problem of elastohydrodynamic lubrication of line contact are obtained by using a finite-difference formulation.

A Study on Vibration Characteristics in Water Tank Structures -Change of Aspect Ratio and Pressure Distribution- (접수 탱크 구조물의 진동특성에 관한 연구 - 종횡비 변화와 압력분포 -)

  • 배성용
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.6
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    • pp.80-87
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    • 2003
  • Tank structures in ships are in contact with various fluid. The vibration characteristics of those structures are strongly affected by the added mass due to containing fluid. It is important to predict vibration characteristics of tank structures, but it is difficult to do. That's because the interaction problem concerned with the free surface, the variation of water depth and stiffener is to be considered between the fluid and the structure. Many authors have studied vibration of rectangular tank structures containing water. Kito studied added mass effect of water in contact with thin elastic flat plates. Kim et al. studied flexural vibration of stiffened plates in contact with water. However, few researches on dynamic interaction tank walls with water are reported in the vibration of rectangular tanks recently. in the present report, the coupling effect of added mass of fluid and structural constraint between panels on each vibration mode changing breadth of elastic plate, and dynamic pressure distribution have investigated numerically and discussed.

A parametric study of bolt-nut joints by the method of finite element contact analysis (유한 요소 접촉 해석법에 의한 나사 체결부 설계 개선에 관한 연구)

  • 이병채;김영곤
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.3
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    • pp.353-361
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    • 1989
  • A parametric study of load distribution in bolt-nut joints is performed by the method of finite element contact analysis. The contacting surface is assumed unbonded and frictionless. Multi-body contact analysis is performed in elastic region under the assumption of axi-symmetric stress state. Load acting on the first thread from the fastened plate is much greater than that on the other threads in the standard setting. But the load distribution is shown to be improved by making the center of contact force acting on the nut surface move outwards. Such a modification is possible by enlarging the gap between bolt shank and fastened plate or by inserting suitable washers. Shape modification of the standard nut by the making a groove and a step on the nut surface is also suggested, which results in almost uniform load distribution and considerable decrease in the maximum stress of the joint.

Response of a completely free beam on a tensionless Pasternak foundation subjected to dynamic load

  • Celep, Z.;Guler, K.;Demir, F.
    • Structural Engineering and Mechanics
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    • v.37 no.1
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    • pp.61-77
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    • 2011
  • Static and dynamic responses of a completely free elastic beam resting on a two-parameter tensionless Pasternak foundation are investigated by assuming that the beam is symmetrically subjected to a uniformly distributed load and concentrated load at its middle. Governing equations of the problem are obtained and solved by paying attention on the boundary conditions of the problem including the concentrated edge foundation reaction in the case of complete contact and lift-off condition of the beam ina two-parameter foundation. The nonlinear governing equation of the problem is evaluated numerically by adopting an iterative procedure. Numerical results are presented in figures to demonstrate the non-linear behavior of the beam-foundation system for various values of the parameters of the problem comparatively by considering the static and dynamic loading cases.

Dynamic Contact of a Cantilever Beam with Rigid Wall Condition (강체벽과 충돌하는 한단이 고정된 외팔보의 진동)

  • Park, Nam-Gyu;Jang, Young-Ki;Kim, Jae-Ik;Kim, Kyu-Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.436-439
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    • 2005
  • Dynamic contact of a cantilever beam with Sap at the end is discussed. The gap in a structure induces dynamic contact, and the contact problem is always accompanied by inequality constraints which mean that the solution of the structure with contact condition should satisfy variational inequality. Inequality, but, can be reduced to equality condition considering convex penalty function. In this paper, formulation of a beam with contact is derived using quasi convex penalty function. General coordinate solution which is needed to increase computational efficiency is applied. Nonlinear behavior of a beam with rigid and elastic contact condition was discussed.

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A Measurement of Adhesion Energy between Viscoelastic/Elastic, Viscoelastic/Viscoelastic Materials Using Contact Mechanics Approach (접촉 역학적 접근에 의한 점탄성/탄성, 점탄성/점탄성 재료간의 접합 에너지 측정)

  • Lee, C.;Earmme, Y.Y.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1030-1035
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    • 2003
  • The nanoimprint lithography technology makes higher density of semiconductor device and larger capacity of storage media. In this technology the induced damage while detaching polymer pattern from mold should be minimized. In order to analyze the problem, the basic knowledge of adhesion between the polymer and the mold is required. In this study a contact experiment of polyisobutylene specimen with spherical steel tip and polyisobutylene bead tip was conducted using nano indenter. During the contact experiment with various loading rate under load control the contact behavior of viscoelastic material was measured, i.e., the load and displacement between the tip and the specimen were measured. The data was analyzed by HBK model to obtain the stress intensity factor of contact edge and the contact radius as a function of time. Also the adhesion energies between steel/polyisobutylene and polyisobutylene/polyisobutylene were obtained employing the analysis of the crack of viscoelastic material by Schapery.

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Finite Element Analysis of the Tire Contact Problem (타이어 접지문제의 유한요소 응력해석)

  • Han, Y.H.;Kim, Y.H.;Huh, H.;Kwak, Y.K.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.5
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    • pp.820-830
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    • 1989
  • The tire inflation and contact problem has been solved by a finite element method. The finite element formulation is derived from the equilibrium equations by the principle of virtual work in the form of an updated Lagrangian formulation for incremental analysis. Then, a contact formulation is added to the finite element formulation to calculate stress state of tire in contact with flat rigid road under the load due to the self-weight of a vehicle. In the finite element analysis, equations of effective material properties are introduced to analyze a plane strain model of the shell-like tire by considering the bending effect of reinforced steel cords. The proposed equations of effective material properties produced stress concentration around the edge of belt layers, which does not appear when other well-known equations of material properties are adopted. The result from the above algorithm demonstrates the validity of the formulation and the proposed equations for the effective elastic constants. The result fully interprets the cause of separation between belt layers by showing the stress concentration.

Deformation Characteristics of Gear System with a Profile Shift Coefficient Preserving Center Distance (중심 거리 불변의 전위 계수를 적용한 기어 시스템의 변형 특성 해석)

  • Park, Su-Jin;Yoo, Wan-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.1
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    • pp.194-199
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    • 2003
  • In this paper, elastic deformations of several gear teeth are analyzed. The contact between a gear and pinion is modeled as a contact problem. The deformation overlap, which is defined as the interference due to deformation of gear teeth, is defined to represent the deformation characteristics of profile shifted spur sear system. The calculated deformation overlap shows teeth interference in the deformed state of a Rear system.