• Title/Summary/Keyword: contact behavior

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Effects of Combination of the Load and the Apparent Area of Contact on Sliding Wear behavior of Mild Steel in a Pin-on-disc Type Apparatus (Pin-on-Disc식 미끄럼마모시험 시 마모 거동에 미치는 접촉면적 및 하중 조합의 영향)

  • Lee, Han-Young
    • Tribology and Lubricants
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    • v.29 no.2
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    • pp.85-90
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    • 2013
  • The effects of contact pressure on the sliding wear behavior of mild steel in a pin-on-disc type apparatus were investigated. Sliding wear tests were conducted with various combinations of the load and apparent area of contact. The wear behavior of mild steel as a function of sliding speed was independent of contact pressure. However, the wear rate at different sliding speeds was influenced by the load regardless of the apparent area of contact. This was attributed to the fact that there may be no difference in the real area of contact for any combination of the load and apparent area of contact.

Difference of Purchase Behavior of Appearance Orientation, Appearance Evaluation, and Fashion Product Purchase Behavior on Media Contact Responses -Focused on Chinese Students in Korea- (미디어 접촉반응에 따른 외모지향과 외모평가, 외모 관련 상품 구매행동 차이 연구 -국내 중국인 유학생을 중심으로-)

  • Jun, Ji-Hyun;Lee, Mi-Sook
    • Journal of the Korean Society of Clothing and Textiles
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    • v.39 no.4
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    • pp.576-585
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    • 2015
  • This study examined difference of purchase behavior of appearance orientation, appearance evaluation, and fashion product purchase behavior on media contact responses. Data were collected from 315 female Chinese university students in Daejeon and Chungnam from May to June 2013. Data were analyzed by descriptive statistics, t-test, correlation, crosstabs analysis with the SPSS-WIN 20.0 program. The results of this study were as follows. First, media contact responses correlated appearance orientation and appearance evaluation. The active group of media contact responses indicated a more active appearance orientation and appearance evaluation. Second, the active group of media contact responses were fashion product purchase behavior. This study verified the relationship of media contact responses and appearance variables-appearance orientation, appearance evaluation, and fashion product purchase behavior.

Contact Pressure Effect on Frictional Behavior of Sheet Steel for Automotive Stamping (자동차용 강판의 표면 마찰 특성에 대한 접촉 압력의 영향)

  • Han, S.S.
    • Transactions of Materials Processing
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    • v.20 no.2
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    • pp.99-103
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    • 2011
  • Many parameters influence the frictional behavior of steel sheet during stamping. The contact pressure between a die and a sheet during stamping is one of them. Thus, this parameter is investigated for high strength steel (HSS) sheets, which are widely used for auto body panels due to their potential for weight reduction. Since HSS extend the limits of contact pressure for mild steel, the effect of this parameter on friction cannot be ignored. To investigate the influence of contact pressure on the frictional behavior of steel sheets, a flat type of friction test was conducted on three different steel sheets under various contact pressures. For bare steel sheets, the curve representing the relationship between contact pressure and friction coefficient exhibits a U shape. Coated steel sheets show a similar tendency except at low contact pressure. For these materials, when the contact pressure is very low, the friction coefficient slightly increases with pressure before it starts to decrease. The test results show that the effect of contact pressure on frictional behavior of steel sheet is not negligible even for contact pressures that are lower than the strength of HSS sheet.

Determination of Contact Area of Cylindrical Nanowire using MD Simulation (MD 시뮬레이션을 이용한 실린더 형태 나노와이어의 접촉면적에 관한 연구)

  • Kim, Hyun-Joon
    • Tribology and Lubricants
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    • v.32 no.1
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    • pp.9-17
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    • 2016
  • Contact between solid surfaces is one of the most important factors that influence dynamic behavior in micro/nanoscale. Although numerous theories and experimental results on contact behavior have been proposed, a thorough investigation for nanomaterials is still not available owing to technical difficulties. Therefore, molecular dynamics simulation was performed to investigate the contact behavior of nanomaterials, and the application of conventional contact theories to nanoscale was assessed in this work. Particularly, the contact characteristics of cylindrical nanowires were examined via simulation and contact theories. For theoretical analysis, various contact models were utilized and work of adhesion, Hamaker constant and elastic modulus those are required for calculation of the models were obtained from both indentation simulation and tensile simulation. The contact area of the cylindrical nanowire was assessed directly through molecular dynamics simulation and compared with the results obtained from the theories. Determination of the contact area of the nanowires was carried out via simulation by counting each atom, which is within the equilibrium length. The results of the simulation and theoretical calculations were compared, and it was estimated that the discrepancy in the results calculated between the simulation and the theories was less than 10 except in the case of the smallest nanowires. As the result, it was revealed that contact models can be effectively utilized to assess the contact area of nanomaterials.

Finite Element Analysis of Contact Pressure Behavior in Compression Ring-Oil Film (압축링-유막간의 접촉압력 거동에 관한 유한요소해석)

  • 김청균;김한구;한동철
    • Tribology and Lubricants
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    • v.11 no.4
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    • pp.53-57
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    • 1995
  • The contact pressure behavior is examined by means of a finite element analysis. The oil film between the piston ring and cylinder liner is analyzed on the basis that it behaves like a polymer material. The calculated results indicate that a shape of sloping edge with a straight line, which is designated as a Model III, shows a good performance on the contact pressure behavior for the increased speed. Obviously, the ring face profiles play an important role on the contact pressure between compression ring and oil film.

Finite Element Analysis of Adhesive Contact of Torus-Shaped Bumps (토러스형 돌기의 흡착접촉 유한요소해석)

  • 조성산;양승민
    • Tribology and Lubricants
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    • v.18 no.4
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    • pp.249-254
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    • 2002
  • Adhesive contact characteristics of torus-shaped bumps were analyzed using the finite element technique considering the adhesive force. Analyses focused on the effect of rim and bump radii on the adhesive contact behavior such as the jump-to-contact behavior, adhesion hysteresis, pull-off forces, contact region and pressure, and surface and subsurface stresses. Analysis results in the absence of adhesive force were also included to examine the effect of adhesive force. The applicability of torus-shaped bumps to the MEMS structure for reduction of friction is discussed.

Effect of Multiple Contact Spots Simulated by Array of Balls on Contact Resistance (볼군의 다수 접촉점이 접촉저항에 미치는 영향)

  • ;Myshkin,N.K.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.11
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    • pp.2967-2972
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    • 1994
  • The multiple character of the contact interaction and the collective behavior of elementary microcontacts play a significant role in all the processes occurring in the surface layers, including the failure due to friction and wear. The array of metal spheres compressed between flat plates has been used for simulation of the contact behavior of multiple contact of solids under normal loading. An experimental design has been made providing regular array of the spheres at the same size with different spatial order. Measurement of electrial contact resistance has been made using the equipment providing the adequate accuracy in the range of micro Ohms. The data on electrical contact resistance have been compared with theoretical predictions using the multiple contact model of constriction resistance. The effect of single spots number and array on conductivity of contact has been evaluated.

Vibration Behavior of a Rotating Brush Roll in Contact with a Solid Roll (강체롤과 접촉 회전하는 브러시롤의 진동 현상)

  • 허주호
    • Journal of KSNVE
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    • v.7 no.3
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    • pp.499-509
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    • 1997
  • During the process of oxide removal from work rolls in sheet metal manufacture, filamentary brushes frequently exhibit a bouncing or chatter behavior. The dynamics of this phenomenon is investigated through the development of expressions for the non-linear contact stiffness between the brush and the roll. With formulation of simple structural models, the time responses in the presence and absence of friction under random excitation are investigated. Possible solutions for the minimization or avoidance of this bouncing or chatter problem are also suggested.

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An Analytic Study on the Contact Stress and Thermal Stress of Rails (레일의 라체팅에 미치는 접촉응력 및 열응력에 대한 해석적 연구)

  • Goo, Byeong-Choon;You, Won-Hee
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.767-774
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    • 2007
  • Even though a constant repeated load is applied, plastic deformation may cumulate. This kind of behavior is called ratcheting. Ratcheting may lead to cracks and finally to failure of the rail. Usually ratcheting occurs on high rails in curves. Ratcheting is influenced by residual stresses, wheel-rail contact stresses, thermal stresses due to wheel/rail rolling contact, shear strength of the rail, strain hardening behavior, etc. In this study, contact stresses and thermal stresses are examined. It is found their value is considerable compared to the maximum contact pressure.

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Study of Frictional Behavior of AZ31B Mg Alloy at Elevated Temperature (AZ31B 마그네슘 합금의 온간 마찰 특성 연구)

  • Han, S.S.
    • Transactions of Materials Processing
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    • v.27 no.3
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    • pp.160-164
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    • 2018
  • The success of warm forming of Mg alloy sheets is very dependent on its frictional behavior at elevated temperatures. The effects of contact pressure and sliding length on the frictional characteristics of AZ31B Mg alloy sheet were investigated at elevated temperature and at room temperature. The contact pressure range for the friction test was determined through FE analysis of the roof panel which is a candidate for Mg alloy application. According to the experimental results, the frictional behavior of the Mg alloy sheet is equally highly influenced by both sliding length and contact pressure at room temperature. At elevated temperatures, however, the sliding length has a more dominant influence on the frictional characteristics of the Mg alloy sheet than the contact pressure, if the contact pressure is lower than a certain level.