• Title, Summary, Keyword: Wear

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Friction and Wear Characteristics of Silica/Epoxy Composites for various Particle Size (입자지름의 변화에 따른 실리카 복합재료의 마찰 및 마모 특성)

  • Koh, Sung-Wi;Kim, Hyung-Jin;Kim, Kae-Dong;Kim, Chang-Soo
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.141-144
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    • 2006
  • In this study, the friction and wear characteristics of pure epoxy and silica-filled epoxy resin composites with average silica particle diameter of $6-33{\mu}m$ were investigated at ambient temperature by pin-on-disc friction test. The cumulative wear volume, friction coefficient and wear rate of these materials against SiC abrasive paper were determined experimentally. The cumulative wear volume tended to increase nonlinearly with increase of sliding distance and depended on diameter of the silica particle for all these composites. The sliding wear tests of the materials demonstrated that the friction coefficient and the wear rate of silica filled epoxy composites were lower than those of the pure epoxy. silica filled epoxy.

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Time-Aware Wear Leveling by Combining Garbage Collector and Static Wear Leveler for NAND Flash Memory System

  • Hwang, Sang-Ho;Kwak, Jong Wook
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.3
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    • pp.1-8
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    • 2017
  • In this paper, we propose a new hybrid wear leveling technique for NAND Flash memory, called Time-Aware Wear Leveling (TAWL). Our proposal prolongs the lifetime of NAND Flash memory by using dynamic wear leveling technique which considers the wear level of hot blocks as well as static wear leveling technique which considers the wear level of the whole blocks. TAWL also reduces the overhead of garbage collection by separating hot data and cold data using update frequency rate. We showed that TAWL enhanced the lifetime of NAND flash memory up to 220% compared with previous wear leveling techniques and our technique also reduced the number of copy operations of garbage collections by separating hot and cold data up to 45%.

Wear Behaviours of Dental Composite Resins Containing Prepolymerized Particle Fillers (1st Report) (유기복합필러를 포함하는 치과용 콤포짓트 레진의 마모거동(제1보))

  • 임정일;김교한;김석삼
    • Tribology and Lubricants
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    • v.15 no.2
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    • pp.212-217
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    • 1999
  • The wear characteristics and wear mechanisms of dental composite resins were investigated. Composite resins such as Metafil, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to evaluate the effect of Prepolymerized Particle Fillers in friction and wear characteristics. Ball on flat wear tester was used for the wear test at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistances of Silux Plus and Palfique Estelite were better than that of Metafil and Heliomolar at the same experimental condition. It was found that The main wear mechanism is plastic flow and abrasive wear by failure of filler's bond to the matrix.

Evaluation and Analysis of Wheel alignment Effecting on Tire Uneven Wear (휠 얼라이먼트 값과 타이어 편마모 영향도 평가 및 분석)

  • Chung, Soo-Sik;Jung, Won-Wook;Lee, Sang-Ju;Koh, Bum-Jin;Choi, Young-Sam
    • Proceedings of the KSME Conference
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    • pp.1658-1662
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    • 2007
  • The tire uneven wear has been an ongoing concern for a long time, and one of customer's complaints too. This paper deals with uneven wear improvement of passenger car tires, to have tested the tire wear levels by each wheel alignment set (according to changing toe and camber) using taxis. The pre-set wheel alignments on test vehicle were gained by energy friction simulation of tire. The result of this experiment was as follows : First, verified the effects of initial wheel alignment (adjusted at Curb Vehicle Weight) to minimize tire uneven wear. Second, tire uneven wear makes tire life much shorter than even wear does.

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Analysis of Sliding Wear Mode on Hardened Steel by X-ray Diffraction Technique (X선회절에 의한 철강재료의 미Rm럼 마모형태 해석에 관한 연구(고경도강에의 적용))

  • 이한영
    • Tribology and Lubricants
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    • v.20 no.1
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    • pp.7-13
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    • 2004
  • High strength steels are widely used as tribo-materials in the field. Previous study revealed that for mild steel, the states of strain on the worn surface measured by X-ray diffraction has a good relationship with the state of wear. The objective of this study is to identify the relationship between the state of strain on the worn surface and the state of wear in high strength steels. Sliding wear tests were carried out using several hardened steels. X-ray diffraction tests were conducted to analyze the state of strain on the worn surface during wear. The experimental results indicated that the state of strain on worn surface in the hardened steel shows the same tendency as in the mild steel. It is clear that change of half value width on the worn surface as a function of sliding speeds is broadly similar in shape to wear characteristics curve and its magnitude has a good relationship with the wear rate at two different wear modes in the hardened steel.

Effects of Gap between Tube and Support Plate on the Steam Generator Tube Wear (증기발생기 세관과 지지대 간극이 세관 마모에 미치는 영향)

  • Park, Chi-Yong;Lee, Yong-Son;Boo, Myung-Hwan;Kim, Tae-Ryong;Kim, Tae-Soon
    • Proceedings of the KSME Conference
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    • pp.302-307
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    • 2004
  • The major flow-induced vibration mechanisms such as fluid-elastic and turbulence excitation can cause the various types of wear of the steam generator tubes in unclear power plant. It is generally accepted that the tube wear due to vibration is affected by the presence of gap clearance between tube and support plate. Connors showed that the tube wear depth could be estimated by using the relationship between wear volume and sliding distance for contact time. Au-Yang predicted the wear depth by using the nonlinear characteristics of normal work rate to contact time. In this study the effect of gap size on the steam generator tubes wear is analyzed by deriving the wear depth versus normal work rate relationship from these previous results.

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Nano Wear Behavior of a-C Films with Variation of Surface Roughness (표면거칠기의 변화에 따른 a-C 박막의 나노마멸 거동)

  • 채영훈;장영준;나종주;김석삼
    • Tribology and Lubricants
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    • v.20 no.3
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    • pp.125-131
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    • 2004
  • Nano-wear behavior of amorphous carbon films was studied by Atomic Force Microscopy. The a-C films are deposited on Si(100) substrate by DC magnetron sputtering method. The influences of different surface roughness on the nano-wear are investigated. Nano-wear tests were carried out using a very sharp diamond coated tip. Its spring constant was 1.6 N/m and radius of curvature was 110 nm. Normal force used in the wear tests ranged 0 to 400 nN. It was found that surface depression occurred during scratching because of plastic deformation and abrasive wear (cutting St ploughing). Wear depth increased linearly with normal force. Changing the surface roughness variables according to the bias pulse control, the less surface roughness decreased the wear depth. The thickness did not affect the wear resistance.

Friction and Wear Characteristics of Carbon Fiber Reinforced Composites against Lay-up Orientation (CFRP 복합재의 적층방향에 대한 마찰 및 마모 특성)

  • Koh, S.W.;Choi, Y.K.
    • Journal of Power System Engineering
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    • v.9 no.2
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    • pp.57-64
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    • 2005
  • This paper is the study on dry sliding wear behavior of carbon fiber reinforced epoxy matrix composites against lay-up orientation. Tests were investigated on the effect of the lay-up orientation, fiber sliding direction, load and sliding velocity when circumstance keep continuously at $21^{\circ}C$, 60%RH. Pin-on-disk dry sliding wear tests for each experimental condition were carried out with a carbon fiber reinforced plastic pin on stainless steel disk in order to search the friction and wear characteristics. The wear rates and friction coefficients against the stainless steel counterpart were experimentally determined and the wear mechanisms were microscopically observed. The effect on friction and wear behavior are observed differently, according to various conditions. When sliding took place against counterpart, the highest wear resistance and the lowest friction coefficient were observed in the $[0]_{24s}$ lay-up orientation at anti-parallel direction.

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Wear-characteristics variation of Fe-C-N alloy with changing content of carbon and nitrogen (탄소와 질소 함량에 따른 탄질소 복합첨가강의 내마멸 특성 변화)

  • Park, J.K.;Yi, S.K.;Kim, S.J.;Kim, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.385-388
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    • 2009
  • Dry-sliding-wear behavior of Fe-18Cr-l0Mn steel with various carbon and nitrogen contents was characterized, and the effect of carbon and nitrogen contents on the wear was investigated. Dry sliding wear tests of the steel were carried out at room temperature against an AISI 52100 bearing steel ball using a pin-on-disk wear tester. Applied wear loads were varied from 10 N to 100 N, and the sliding distance was fixed as 720 m. Worn surfaces and the wear debris of the steel were examined using an SEM to find out the wear mechanism. It was found that the Fe-18Cr-10Mn with both carbon and nitrogen exhibited superior wear resistance to the steel with only nitrogen. The wear resistance of the Fe-18Cr-10Mn-xC-yN alloy increased with the increase of the carbon content. The excellent wear resistance of the Fe-18Cr-10Mn-xC-yN alloy was explained by the increased strain-hardening capability with the interstitial atoms.

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Real Time Analysis of Friction/Wear Characteristics of Metal Coatings with a Tribo-tester Installed in an SEM (SEM 내부에 설치된 트라이보 시험기를 통한 금속 코팅의 실시간 마찰/마모 특성 분석)

  • Kim, Hae-Jin;Kim, Dae-Eun;Kim, Chang-Lae
    • Tribology and Lubricants
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    • v.34 no.6
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    • pp.318-324
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    • 2018
  • This study aims to visualize the friction and wear behaviors of metal coatings in real time. The main mechanism of wear is identified by observing all the processes in which wear occurs. The friction coefficients of the moments are monitored to confirm the relationship between the friction and wear characteristics of the coating. Thin Ag coatings, which are several hundred nanometers in thickness, are prepared by depositing Ag atoms on silicon substrates through a sputtering method. A pin-on-disk-type tribo-tester is installed inside a scanning electron microscope (SEM) to evaluate the friction and wear characteristics of the Ag coating. A fine diamond pin is brought into contact with the Ag coating surface, and a load of 20 mN is applied. The contact pressure is calculated to be approximately 15 GPa. The moments of wear caused by the sliding motion are visualized, and the changes in the friction characteristics according to each step of wear generation are monitored. The Ag coating can be confirmed to exhibit a wear phenomenon by gradually peeling off the surface of the coating on observing the friction and wear characteristics of the coating in real time inside the SEM. This can be explained by a typical plowing-type wear mechanism.