• Title/Summary/Keyword: Dry Friction

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Seismic Rocking Response Analysis of 1/8 Scale Model for a Spent Fuel Storage Cask (사용후 연료 건식저장용기 1/8규모 축소모형 지진회전응답해석)

  • Lee J.H.;Seo K.S.;Koo G.H.;Cho C.H.;Choi B.I.;Lee H.Y.;Yeom S.H.
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.383-389
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    • 2005
  • This research is to develop a seismic response analysis method for a spent fuel storage cask. FEM model is built for the test model of 1/8 scale spent fuel dry storage cask using available 3D contact conditions in ABAQUS/Explicit. Input load for this analysis os a seismic wave of El-centro earthquake, and the friction and damping coefficients in the analysis condition we obtained from the test result. Penalty and kinematic contact methods of ABAQUS are used for mechanical contact formulation. The analysis method was verified for rocking angle obtained by seismic response tests. The kinematic contact method with an adequate normal contact stiffness showed a good agreement with tests.

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Effects of Counterpart Materials on Dry Sliding Wear and Friction Behavior of Co-Fe, Co-Ni Bond Materials for Diamond Tools (다이아몬드 공구용 Co-Fe, Co-Ni 본드 소재의 마멸상대재에 따른 건식 미끄럼 마찰 및 마멸거동)

  • 권용진;김용석
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.03a
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    • pp.28-28
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    • 2003
  • 고온가압소결(Hot Pressing) 된 다이아몬드 공구용 Co-Fe, Co-Ni계 금속본드의 상온 건식 미끄럼 마멸시험을 행하고, 조성에 따른 각 본드의 마멸 특성을 비교하고 마멸 기구를 규명하였다. 미끄럼 마멸시험은 pin-on-disk 형태의 마멸시험기를 사용하여 각 조성의 성분, 적용하중 그리고 마멸상대재를 변수로 상온, 대기 중에서 실시되었다. 마멸속도는 마멸시험 전후의 시편의 무게 감량을 이론밀도와 거리로 나누어 계산되었다. 마멸기구의 규명을 위하여 시험된 시편의 마멸면과 마멸단면을 SEM과 EDS를 이용하여 분석하였다. 시험 결과 Co-Fe system의 경우 그 마멸속도는 마멸상대재의 영향보다는 Fe 첨가에 따른 시편의 미세조직과 기계적 성질의 차이에 따라 크게 변화하였다. 그러나 Co-Ni system의 마멸속도는 마멸 상대재에 따라 크게 변화하는 것이 관찰되었다. $Al_2$O$_3$를 상대재로 마멸된 경우에는 마멸속도가 시편/상대재 접촉면에서 형성되는 산화층의 영향을 크게 받았고, glass bead(83% SiO$_2$)를 상대재로 한 경우에는 시편의 경도와 마멸속도는 서로 반비례하였다.

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Effect of the Liquid Circulation Velocity on the Biofilm Development in an IFBBR (역 유동층 생물막 반응기에서 액체순환속도가 생물막에 미치는 영향)

  • 김동석;윤준영
    • Journal of Environmental Science International
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    • v.3 no.1
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    • pp.49-56
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    • 1994
  • Effect of the liquid circulation velocity on the biofilm development was investigated in an inverse fluidized bed biofilm reactor(IFBBR). To observe the effect of the influent COD concentration on biofilm simultaneously, the influent COD value was adjusted to 1000mg/1 f for 1st reactor, and 2500mg/l for 2nd reactor. The liquid circulation velocity was adjusted by controlling the initial liquid height. As the liquid circulation velocity was decreased, the settling amount of biomass was increased and the amount of effluent biomass was decreased. Since the friction of liquid was decreased by the decrease of liquid circulation velocity, the biofilm thickness was increased and the biofilm dry density was decreased. In the 1st reactor the SCOD removal efficiency was constant regardless of the variation of the liquid circulation velocity, but it was increased by the decrease of the liquid circulation velocity because of more biomass population in 2nd reactor.

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A Study on the Formation and the Tribological Role of Mass Transfers Layers at Rubbing Silver-coated Surface (은 박막이 코팅된 표면에서 물질전이층의 형성 및 그 트라이볼로지적 역할에 관한 연구)

  • 공호성;양승호;윤의성;김대은
    • Tribology and Lubricants
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    • v.18 no.6
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    • pp.377-383
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    • 2002
  • The tribological role of mass transfer layer was studied with silver coatings under various ranges of load and sliding speed. Silver coating was performed with a functionally gradient coating method. Tests were per-formed in dry sliding conditions, using a ball-on-disk contact configuration, at the load of 0.0196-17.64 N and the sliding speed of 20-1,000 mm/s in ambient air. Optical microscope and EPMA analyses showed that contact surfaces were covered with the mass transfer layers of agglomerated wear particles depending upon the contact conditions, and they greatly influenced the tribological characteristics of the surfaces. However, the formation of mass transfer layer was suppressed as the sliding speed increased, and above a critical sliding speed, no mass transfer layer was able to form. For building up a general framework of triboiogical behavior of the coated silver films, all test data were summarized on a map whose axes are contact pressure and sliding speed.

Wear Characterisitics of TiN-coated Boron Cast Iron by Arc Evaporation Process (CAE 증착기술에 의해 TiN이 증착된 보론주철의 마모거동)

  • Song, Kun;Yoon, Eui-Sung;Ahn, Hyo-Sok
    • Tribology and Lubricants
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    • v.8 no.1
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    • pp.63-69
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    • 1992
  • In order to gain better understanding of wear behaviors of TiN-coated boron cast iron, tests and analyses were conducted with block-on disc type tribometer. TiN layer of thickness $2 \mu m$ and $4 \mu m$, coated by cathodic arc evaporation process, were experimentally investigated with the variation of applied load and sliding speed under dry sliding condition. Wear characteristics were expressed in terms of the three-dimentional wear map as well as the wear rate vs sliding speed and load. Comparisons of wear and friction characteristics between coated cast irons and uncoated cast irns were also made. Wear mechanism of TiN layer was explained in view of surface interaction between the mating surfaces. The thicker coating exhibited higher hardness and adhesion strength. the significance of stresses at the surface and in the subsurface was briefly discussed in relation to the wear behavior.

Effects of thickness and applied load on wear mechanisms of PMMA (Poly Methyl Methacrylate) coating layers (PMMA(Poly Methyl Methacrylate) 코팅층 두께 및 적용하중에 따른 마멸기구 분석)

  • Kang S. H.;Kim Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.152-155
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    • 2004
  • Effects of sliding speed, applied load, counterpart radius and thickness of PMMA (Poly Methyl Methacrylate) coating layers on their dry sliding frictional and wear behavior were investigated. Sliding wear tests were carried out using a pin-on-disk wear tester. The PMMA layer was coated on Si wafer by a sol-gel technique with two different thicknesses, $1.5{\mu}m\;and\;0.8{\mu}m$. AISI 52100 bearing steel balls were used as a counterpart of the PMMA coating during the wear. Normal applied load and sliding speed were varied. Wear mechanisms were investigated by examining worn surfaces by an SEM. Under most of sliding test conditions, the thicker layer with the thickness of $1.5{\mu}m$ showed lower fiction coefficient than the thinner layer. Effects of sliding speed and counterpart's radius on the frictional behavior were varied depending on the thickness of the coating layer.

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The Effects of the Annealing Temperature and Environments on Room Temperature Wear Behavior of Plasma-Sprayed Partially Stabilized Zirconia Coatings (플라즈마 용사된 부분안정화 지르코니아 코팅의 상온 마모거동에 미치는 열처리온도 및 분위기의 영향)

  • 김장엽;임대순
    • Journal of the Korean Ceramic Society
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    • v.31 no.10
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    • pp.1176-1180
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    • 1994
  • The sliding wear behavior of the plasma-sprayed zirconia containing 3 mol% yttria was investigated after the annealing at room temperature to 80$0^{\circ}C$ in various concentrations of humid atmosphere as laboratory, humid, dry argon atmosphere. Both of the friction coefficient and the wear loss increased with increasing temperature up to 80$0^{\circ}C$. Surface morphology of the worn samples changed with annealing temperature. The change of monoclinic/tetragonal (m/t) x-ray peak intensity ratio effected the wear behavior. The m/t ratio had maximum value at 20$0^{\circ}C$ and decreased with increased temperature in laboratory and humid atmosphere. In argon atmosphere the m/t ratio had no maximum value and decreased with increasing temperature. At all the annealing temperature humid atmosphere had more the m/t ratio value than any other atmosphere. The change of toughness was showed the inversed result of m/t ratio change. The results indicated that the resudial stress which was induced by the different amount of phase transformation takes a detrimental role in wear behavior.

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Dry Etching Characteristic of TiN Thin Films using Inductively Coupled Plasma (TiN 박막의 건식 식각 특성)

  • Park, Jung-Soo;Kim, Chang-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.383-383
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    • 2010
  • TiN is one of the mostly used barrier materials in copper metallization because of low friction coefficient and superior electrical properties. We need to investigate for the etching characteristic of TiN. In this study, we investigated about etching characteristic of TiN using $BCl_3$/Ar inductively coupled plasma system. The etch rate was measured by a depth pro filer. The chemical etching reactions of the TiN surface was investigated X-ray photoelectron spectroscopy.

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Wear Behaviors of Ceramics TIN, TIC and TICN with Arc Ion Plating

  • Oh, Seong-Mo;Rhee, Bong-Goo;Jeong, Bong-Soo
    • Journal of Mechanical Science and Technology
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    • v.17 no.12
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    • pp.1904-1911
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    • 2003
  • In order to determine the wear properties of AIP (Arc Ion Plating) deposition, wear process was evaluated by using a Falex test machine. Also, in order to determine the effects of coating material on the wear process, TiC, TiN, and TiCN coatings of thickness about 5 $\mu\textrm{m}$∼6 $\mu\textrm{m}$ coated by Arc ion plating deposition method were tested. The wear property was determined under a dry sliding condition as a function of the applied load, sliding distance, sliding velocity and temperature. The results show that when wear of the coating-layer occurred, specific wear amount increased with the wear rate. At initial state, the wear rate rapidly increased, but it gradually reduced as the velocity increased. Also, when raising the temperature, the wear rate increased in the order of TiCN, TiN and TiC due to the frictional heat.

Analysis of influence factors on the seismic earth pressure acting on gravity walls (중력식 옹벽에 작용하는 배면 동적 토력의 영향 인자 분석)

  • 윤석재;김성렬;김명모
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.09a
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    • pp.75-82
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    • 2002
  • The Mononobe-Okabe method is generally used to evaluate the dynamic earth force for the seismic design of retaining walls. However, the Mononobe-Okabe method does not consider the effects of the dynamic interactions between the backfill soil and the wall. In fact, a phase difference exists between the inertia force and the seismic earth pressure. In this study, shaking table tests were peformed on gravity walls retaining dry backfill sand to analyze the influence of several parameters (the unit weight of the wall, the input acceleration and base friction) on the development of the seismic earth pressure. The experiments revealed that the magnitude of the inertia force mobilized during seismic loading affected the seismic earth pressure. The difference in the phase angles between the inertia force and the seismic earth pressure was retained at 180 degrees before the wall failed but its magnitude changed significantly as the wall began to fail.

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