• Title/Summary/Keyword: contact law

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Constitutive law for wedge-tendon gripping interface in anchorage device - numerical modeling and parameters identification

  • Marceau, D.;Fafard, M.;Bastien, J.
    • Structural Engineering and Mechanics
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    • v.15 no.6
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    • pp.609-628
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    • 2003
  • Mechanical anchorage devices are generally tested in the laboratory and may be analyzed using the finite element method. These devices are composed of many components interacting through diverse contact interfaces. Generally, a Coulomb friction law is sufficient to take into account friction between smooth surfaces. However, in the case of mechanical anchorages, a gripping system, named herein the wedge-tendon system, is used to anchor the prestressing tendon. The wedge inner surface is made of a series of triangular notches designed to grip the tendon. In this particular case, the Coulomb law is not adapted to simulate the contact interface. The present paper deals with a new constitutive contact/gripping law to simulate the gripping effect. A parameter identification procedure, based on experimental results as well as on a finite element/neural network approach, is presented. It is demonstrated that all parameters have been selected in a satisfactory way and that the proposed constitutive law is well adapted to simulate the wedge gripping effect taking place in a mechanical anchorage device.

Low-Velocity Impact Analysis and Contact Law on Composite Laminates (복합적층판에 대한 저속충격해석과 접촉법칙)

  • 최익현
    • Composites Research
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    • v.16 no.1
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    • pp.50-57
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    • 2003
  • Usually many researchers have used the modified Hertzian contact law or experimental static indentation law to analyze impact response of composite laminates subjected to the low-velocity impact. In this study, physical meaning of the method using the laws was investigated and the difference between the analytical results obtained using the laws was also investigated. Furthermore parametric study on contact constant and exponent in the contact law was performed. Finally it was shown that a linearized contact law can be well applied to low-velocity impact response analysis of composite laminates. If this concept is used, commercial finite element software can be used to solve impact problem without making any auxiliary code.

Analysis of Incipient Sliding Contact with Orthotropic Friction Condition Subjected to Tangential Load and Twisting Moment (접선하중과 비틀림모멘트를 받는 직교이방성 마찰조건의 정지미끄럼접촉 해석)

  • 이성철;곽병만;권오관
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.8
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    • pp.2026-2038
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    • 1994
  • A numerical scheme is developed for the analysis of incipient sliding contact with orthotropic friction condition subjected to tangential load and twisting moment. The inherent nonlinearity in the orthotropic friction law has been treated by a polyhedral friction law. Then, a three-dimensional linear complementarity problem(LCP) formulation in an incremental form is obtained, and the existence of a solution is investigated. A Lemke's complementary pivoting algorithm is used for solving the LCP. The scheme is illustrated by spherical contact problems, and the effects of eccentricity of elliptical friction domain on the traction and stick region are discussed.

VARIATIONAL ANALYSIS OF AN ELECTRO-VISCOELASTIC CONTACT PROBLEM WITH FRICTION AND ADHESION

  • CHOUGUI, NADHIR;DRABLA, SALAH;HEMICI, NACERDINNE
    • Journal of the Korean Mathematical Society
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    • v.53 no.1
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    • pp.161-185
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    • 2016
  • We consider a mathematical model which describes the quasistatic frictional contact between a piezoelectric body and an electrically conductive obstacle, the so-called foundation. A nonlinear electro-viscoelastic constitutive law is used to model the piezoelectric material. Contact is described with Signorini's conditions and a version of Coulomb's law of dry friction in which the adhesion of contact surfaces is taken into account. The evolution of the bonding field is described by a first order differential equation. We derive a variational formulation for the model, in the form of a system for the displacements, the electric potential and the adhesion. Under a smallness assumption which involves only the electrical data of the problem, we prove the existence of a unique weak solution of the model. The proof is based on arguments of time-dependent quasi-variational inequalities, differential equations and Banach's fixed point theorem.

A Modeling of Impact Dynamics and its Application to Impact Force Prediction

  • Ahn Kil-Young;Ryu Bong-Jo
    • Journal of Mechanical Science and Technology
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    • v.19 no.spc1
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    • pp.422-428
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    • 2005
  • In this paper, the contact force between two colliding bodies is modeled by using Hertz's force-displacement law and nonlinear damping function. In order to verify the appropriateness of the proposed contact force model, the drop type impact test is carried out for different impact velocities and different materials of the impacting body, such as rubber, plastic and steel. In the drop type impact experiment, six photo interrupters in series close to the collision location are installed to measure the velocity before impact more accurately. The characteristics of contact force model are investigated through experiments. The parameters of the contact force model are estimated using the optimization technique. Finally the estimated parameters are used to predict the impact force between two colliding bodies in opening action of the magnetic contactor, a kind of switch mechanism for switching electric circuits.

Analysis of low-velocity impact on composite sandwich panels using an assumed strain solid element (가정변형률 솔리드 요소를 이용한 복합재 샌드위치 평판의 저속충격 해석)

  • Park, Jung;Park, Hoon-Cheol;Yoon, Kwang-Joon;Goo, Nam-Seo;Lee, Jae-Hwa
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.7
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    • pp.44-50
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    • 2002
  • Low-velocity impact on composite sandwich panel has been investigated. Contact force is computed from a proposed modified Hertzian contact law. The Hertzian contact law is constructed by adjusting numerical value of the exponent and reducing the through-the- thickness elastic constant of honeycomb core. The equivalent transverse elastic constant is calculated from the rule of mixture. Nonlinear equation to calculate the contact force is solved by the Newton-Raphson method and time integration is done by the Newmark-beta method. A finite element program for the low-velocity impact analysis is coded by implementing these techniques and an 18-node assumed strain solid element. Behaviors of composite sandwich panels subjected to low-velocity impact are analyzed for various cases with different geometry and lay-ups. It has been found that the present code with the proposed contact law can predict measured contact forces and contact times for most cases within reasonable error bounds.

항공기 복합재 구조물의 저속충격 해석방법 분석

  • Choi, Ik-Hyeon
    • Aerospace Engineering and Technology
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    • v.2 no.1
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    • pp.213-222
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    • 2003
  • Some analytical methods to analyze low-velocity impact force history of composite laminated structures used in aerospace vehicles are reviewed. A classical method used at initial research of low-velocity impact problem in 1980s was reviewed on its physical meaning, and the approximate method assuming the shape of impact force history as a sinusoidal wave was reviewed. A parametric study on contact constant and exponent in contact law was performed in order to analyze an effect on impact force history, and finally its was understood that impact force history could be analyzed accurately even though the linearized contact law was used. Also, in this paper it was shown that impact problem could be analyzed simply and easily using a commercial finite element code.

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Frictional Contact Analysis of the compression-Induced Crack Surfaces using the Finite element Method (유한요소법을 이용한 압축력으로 인한 균열 표면의 마찰접촉 해석)

  • 김방원;이기수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.517-522
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    • 2000
  • When a body including a crack inside is subjected to the compressive forces, the crack is closed and sliding occurs on the crack surfaces. In this work, a subsurface crack subjected to a static or moving compressive load is analyzed with the finite element method considering friction on the crack surface. The friction on the crack surface is assumed to follow the Coulomb friction law. A numerical method based on the finite element method and iterative method is applied in this work. And the result is compared with the frictional contact of crack by ANSYS using contact 12 element. The numerical results of two methods are compared with the wellknown analytical solutions, and the accuracy of iterative method is checked..

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Analysis on load-bearing contact characteristics of face gear tooth surface wear with installation errors

  • Fan Zhang;Xian-long Peng
    • Computers and Concrete
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    • v.31 no.2
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    • pp.163-171
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    • 2023
  • Face gear transmission is widely used in aerospace shunt-confluence transmission system. Tooth wear is one of the main factors affecting its bearing transmission performance. Furthermore, the installation errors of face gear are inevitable. In order to study the wear mechanism of face gear tooth surface with installation errors, based on tooth contact analysis numerical method and Archard wear theory, the UMESHMOTION subroutine in ABAQUS is developed.Combining with Arbitrary Lagrangian-Eulerian adaptive mesh technology, the finite element mesh wear model of abraded face gear pair is established.The preprocessing conditions are set to generate the inp files.Then,the inp files for each corner are imported and batch processed in ABAQUS.The loading tooth contact problem at each rotation angle is solved and the load distribution coefficient among gear tooth, tooth root bending stress, tooth surface contact stress and loaded transmission error are obtained. Results show that the tooth root wear is the most serious and the wear at the pitch cone is close to 0.The wear law of tooth surface along tooth width direction is convex parabola and the wear law along tooth height direction is concave parabola.

A Study on the Legal Bases for the Gross Disparity under PICC (국제상사계약에 관한 일반원칙(PICC)하에서 현저한 불균형에 관한 법적 기준)

  • YOON, Sang-Yoon;SHIM, Chong-Seok
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.69
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    • pp.127-151
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    • 2016
  • UNIDROIT Principles of International Commercial Contracts(PICC) was published in 1994. PICC has been functioned as a guideline of international commercial contracts, an applicable law to govern a contract by the agreement of the parties to a contract, general principles of law and lex mercatoria. In addition, PICC has a role of interpreting or supplementing international uniform law instruments as well as domestic laws, and also has served as a model for national and international legislations. PICC has been accepted as a authoritative source of knowledge of international trade usages of international commercial contracts to the arbitral tribunal rather than domestic court because it excluded the characteristics of hard law at the drafting stage. This article dealt with the rule on gross disparity of validity which fall outside the scope of UN Convention on Contract for the International Sale of Goods(CISG), which has obtained a leading legal position of uniform law in international sales of good. In other words, PICC suggests a series of meaningful solutions to the issue of gross disparity of contract which is the most complicated among legal disputes occurring during the process of conclusion of contact and also extremely different and diverse between legal systems. This article covered the issue of gross disparity of contract at the conclusion of contact and suggested the legal basis of several rules related to the gross disparity by analysing gross disparity rule of PICC. Furthermore, this article suggested legal check points or implication as well as interpretation and evaluation on doctrine of laesio enormis and undue influence or unconscionability. This article also dealt with a comparative analysis with Principles of European Contract Law(PECL) and Common European Sales Law(CESL) which have important legal positions in the area of international commercial contract as well as in terms of close relationship to PICC by linking with recent court or arbitral tribunal rulings.

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