• Title, Summary, Keyword: Wear

Search Result 6,978, Processing Time 0.063 seconds

Friction and Wear Behavior of Carbon/Carbon Composites for Aircraft Brake Material (항공기 브레이크 재료용 탄소/탄소 복합재료의 마찰 및 마모 거동)

  • 우성택;윤재륜
    • Tribology and Lubricants
    • /
    • v.9 no.1
    • /
    • pp.62-69
    • /
    • 1993
  • Friction and wear behavior of a carbon/carbon composite material for aircraft brake material was experimentally investigated. Friction and wear test setup was designed and built for the experiment. Friction and wear tests were conducted under various sliding conditions. Friction coefficients were measured and processed by a data acquisition system and amount of wear measured by a balance. Stainless steel disk was used as the counterface material. Temperature was also measured by inserting thermocouple 2.5 mm beneath the sliding surface of the carbon/carbon composite specimen. Wear surfaces were observed by SEM, and analyzed by EDAX. The experimental results showed that sliding speed and normal force did not have significant effects on friction coefficient and wear factor of the composite. Temperature increase just below the surface was not large enough to cause any thermal degradation or oxidation which occurred at higher temperature when tested by TGA. Wear film was generated both on the specimen and on the counterface at relatively low sliding speed but cracks, grooves, and wear debris were observed at high sliding speed. Friction coefficient remained almost constant when the sliding speed or normal load was varied. It is believed that the adhesive and abrasive components contributed mainly to the friction coefficient. Wear behavior at low sliding speed was governed by wear film formation and adhesive wear mechanism. At high speed, fiber orientation, ploughing by counterface asperities, and fiber breakage dominated wear of the carbon/carbon composite.

The Dry Sliding Wear Properties of $SiC_w$ and $SiC_p$ Reinforced Bronze Matrix Composites (무윤활 미끄럼 마찰하에서 SiC 휘스커 및 입자강화 청동기지 복합재의 마모특성)

  • 이상로;허무영
    • Tribology and Lubricants
    • /
    • v.9 no.2
    • /
    • pp.49-55
    • /
    • 1993
  • The dry sliding wear properties of the sintered Cu-10 wt%Sn bronze alloys reinforced with $SiC_w$ and $SiC_p$ were investigated by a pin-on-disc wear testing machine. The worn surfaces and the cross sections of the wear specimens and the wear debris were observed by SEM to study the effect of the variation of the ceramic phase contents in the composite and the wear condition on the wear behaviors. The wear of bronze matrix was dominated by the adhesive wear. The transition from mild to severe wear was found in the bronze matrix specimens at the applied load higher than 20N where the surface delamination caused the severe wear. The addition of $SiC_w$ and $SiC_p$ reinforcements in the romposites was proved to reduce the wear rate by the matrix strengthening at the applied load higher than 20N. SiC whiskers having a large length to diameter ratio which hold the deformed matrix were effective to hinder the crack propagation near the worn surface. Thus the maximum wear resistance was obtained in the composite reinforced by $SiC_w$ at the higher applied load.

A Comparative Study on the Evaluation of the Wear Resistance in Zr-xNb-xSn Alloys

  • Lee, Young-Ho;Kim, Hyung-Kyu;Jung, Youn-Ho
    • KSTLE International Journal
    • /
    • v.4 no.2
    • /
    • pp.47-51
    • /
    • 2003
  • Sliding wear tests have been carried out in room temperature air and water in order to compare the wear resistance of Zr-xNb-xSn alloys of various alloying elements (Nb and Sn). The main focus was to quantitatively compare the wear properties of the recently developed Zr-xNb-xSn alloys with the commercial ones using the evaluation parameters of the wear resistance with the consideration of the worn area. As a result, the recently developed alloys had a similar wear resistance compared with the commercial ones. The dominant factor governing the wear resistance was the protruded volume of the wear debris that was formed on the worn area in the air condition, but the accommodation of the plastic deformation on the contact area in water. In addition, the worn area size appeared to be very different depending on the tested alloys. To evaluate the wear resistance of each test specimen, the ratio of the wear volume or the protruded volume to the worn area ($D_e$ or $D_p$) is investigated and proposed as the evaluation parameters of the wear resistance.

Effects of Test Temperature on the Reciprocating Wear of Steam Generator Tubes

  • Hong, J.K.;Kim, I.S.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.379-380
    • /
    • 2002
  • Steam generators (S/G) of pressurized water reactors are large heat exchangers that use the heat from the primary reactor coolant to make steam in the secondary side for driving turbine generators. Reciprocating sliding wear experiments have been performed to examine the wear properties of Incoloy 800 and Inconel 690 steam generator tubes in high temperature water. In present study, the test rig was designed to examine the reciprocating and rolling wear properties in high temperature (room temperature - $300^{\circ}C$) water. The test was performed at constant applied load and sliding distance to investigate the effect of test temperature on wear properties of steam generator tube materials. To investigate the wear mechanism of material, the worn surfaces were observed using scanning electron microscopy. At $290^{\circ}C$, wear rate of Inconel 690 was higher than that of Incoloy 800. It was assumed to be resulted from the oxide layer property difference due to the a\loy composition difference. Between 25 and $150^{\circ}C$ the wear loss increased with increasing temperature. Beyond $150^{\circ}C$, the wear loss decreased with increasing temperature. The wear loss change with temperature were due to the formation of wear protective oxide layer. From the worn surface observation, texture patterns and wear particle layers were found. As test temperature increased, the proportion of particle layer increased.

  • PDF

AN IN-VITRO WEAR STUDY OF INDIRECT COMPOSITE RESINS AGAINST HUMAN ENAMEL (법랑질에 의한 수종의 간접복합레진의 마모에 관한 연구)

  • Yi, Hyun-Jeong;Jeon, Young-Chan;Jeong, Chang-Mo;Jeong, Hee-Chan
    • The Journal of Korean Academy of Prosthodontics
    • /
    • v.45 no.5
    • /
    • pp.611-620
    • /
    • 2007
  • Statement of problem: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. Purpose: This study was to evaluate the wear of indirect composite resins (SR Adore, Sinfony, Tescera ATL) and gold alloy against the human enamel. Material and method: Extracted human incisors and premolars were sectioned to $2{\times}2{\times}2mm$ cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pin-on-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. Results: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P<.05). Gold alloy was shallower than Sinfony, but there was no statistically significant difference between Sinfony and gold alloy (P>.05). 3. The width of wear tract of SR Adore was larger than the other groups (P<.05), and there were no statistically significant differences among the other groups (P>.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adore showed the most. Conclusion: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

The Effects of Mountain Climbing Motivation and Mountain Climbing Wear Benefits Sought on Clothing Usage Behavior (등산동기가 등산복 추구혜택 및 등산복 착용행동에 미치는 영향)

  • Ahn, Suh Young;Yoon, Seung Won;Lee, Mi Ah;Koh, Ae-Ran
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.37 no.4
    • /
    • pp.565-576
    • /
    • 2013
  • This study investigated 1) the effects of mountain climbing motivation on the desired mountain climbing wear benefits, and 2) the desired effects of mountain climbing wear benefits on clothing usage behavior. Data were collected via a questionnaire administered to 498 consumers who make at least one mountain climbing wear purchase for personal use. All items were evaluated on a 5-point Likert scale, and SPSS 20.0 and Amos 7.0 were used for data analysis. Confirmatory factor analysis for the research variables were performed and three factors of mountain climbing motivation (social interaction, health improvement, and mental rejuvenation), four factors of mountain climbing wear benefits sought (ostentation, ideal healthy figure, conformity, and functions), and two factors regarding clothing usage behavior (sportswear usage and daily wear usage) were identified. The results from the model test were as follows: 1) Mountain climbing motivation was found to vary depending on the mountain climbing wear benefits sought. Social interaction had a positive effect on all 4 factors of mountain climbing wear benefits sought. Health improvement was the only motivating factor for consumers who sought the benefit of functions; however, the functions benefit was not found to be a consideration for consumers who climbed for mental rejuvenation. 2) Mountain climbing wear usage was affected by mountain climbing wear benefits sought. The benefits for conformity and functions had a positive effect on sportswear usage and daily wear usage; however, the ideal healthy figure only affected daily wear usage. The twofold usage of mountain climbing wear reflects a cultural trend toward the usage of mountain climbing wear as daily wear; however, consumers show this twofold usage to conform successfully to mainstream society and not to pursue the ideal healthy figure.

Wear Characteristics of Cylinder-Liner Materials for Diesel Engine at Elevated Temperature (디젤엔진용 실린더 라이너 소재의 고온 마모특성)

  • Kim, Jin-Yeol;Kim, Jae-Hoon;Oh, Kwang-Keun;Lee, Seung-Hak;Chang, Joon-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.39 no.11
    • /
    • pp.1131-1136
    • /
    • 2015
  • In a diesel engine, the wear of the cylinder liner occurs because of the continuous reciprocating motion of the piston ring. This wear reduces the performance of the diesel engine and shortens its service life. This study evaluated the wear characteristics of GT metal and a conventional metal used for cylinder liners using a ship's diesel engine. Wear tests were performed at temperatures of $25^{\circ}C$, $175^{\circ}C$, and $325^{\circ}C$, and under loads of 10 N, 30 N, and 50 N. The amount of wear, specific wear rate, and friction coefficient were evaluated for each condition. To analyze the wear mechanism, observations were made on an SEM. In the case of both metals, abrasive and adhesion wear occurred on the wear surfaces at room temperature, and corrosion wear was observed at high temperatures. The amount of wear and the specific wear rate of the GT metal were lower than those of the conventional metal at all temperatures, and hence it can be concluded that the wear characteristics of the GT metal are much better.

A Study for the Improvement of the Nursery Active-wear Uniform -By Characters based on Children's Folklore Plays- (어린이집 활동복 개발 연구 -아동 민속놀이 캐릭터를 활용하여-)

  • Moon, Myeng Ok;Lee, Jin Suk;Um, Jung Ok
    • Fashion & Textile Research Journal
    • /
    • v.15 no.3
    • /
    • pp.347-357
    • /
    • 2013
  • The nursery active-wear uniform designs of Internet shopping malls are simple and similar; however, the latest children's wear trends (mostly composed of training jumpers and pants) do not reflect these qualities. Children's folklore plays (widely used in child education) have an instructive value for the emotional and intellectual development of a child. Nursery active-wear uniform designs applied to children's folklore's plays could be positive for the emotional development and specialized cultural education of children. We designed three nursery active-wear uniforms with three different design concepts (casual, semi-formal and sporty) regardless of sex. The main color of the three nursery active-wear uniforms was yellow. We used three different chroma and values of yellow through three design concepts: Design I of a nursery active-wear uniform (a training suit style with a good activity), Design II of a nursery active-wear uniform (a semi suit style), and Design III of a nursery active-wear uniform (a sportswear style that reflected a sport wear trend). We expressed children's folklore plays in the pattern of a nursery active-wear uniform. The pattern was characterized as a pair of bears flying kites. This pattern was utilized in three nursery active-wear uniforms with the logo and name of the nursery. We modified the designs of active-wear nursery uniforms based on an evaluation of 33 special panels. We made three nursery active-wear uniforms for five-year olds.

The Design Development of Easy Casual Wear for Career Women (직장여성을 위한 이지 캐주얼 웨어 디자인 개발)

  • Byun, Mi-Yeon;Lee, In-Seong
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.30 no.8
    • /
    • pp.1301-1311
    • /
    • 2006
  • This study rearranged a concept of Friday wear considered as casual wear by searching social background through analysis of literature study and photo materials and classifying by characteristics of casual wear. It investigated growing changes of casual wear and the progress of changes casual brands through a market survey based on departments in Seoul. And then, it examined characteristics of a design and the critical point of easy casual selecting GIORDANO, TBJ and NII of three easy casual brands. Conclusions of the study are as follows: Firstly, present casual wear showed subdivision of casual wear as abundant grouping vocabularies appeared contrary to the past. Secondly, easy casual wear has continuously increased by results of investigating departments in Seoul on the progress of changing easy casual wear brand including the concept of Friday wear. Thirdly, if a main target sets the early 20s, women workers in their 20's and 30's are likely to be reluctant to wear it according to results of investigating designs and characteristics based on GIORDANO, TBJ and NII of existing three easy casual brands through the market survey. Also, it was verified that most of these brands have no a luxurious image because they adhere to middle-low price. Fourthly, it improved problems of easy casual through developing designs of easy casual wear. Easy casual wear supplementing weak these points of easy casual wear was evaluated as suitable clothes for workers to wear in on and off their own time in Friday.

On the Abnormal Wear of Cylinder Liners and Piston Rings of the Marine Diesel Engine (박용(舶用) 디이젤기관(機關)의 실린더 라이너 및 피스턴 링의 이상마모(異常摩耗)에 관(關)하여)

  • Tae-Choon,Chung
    • Bulletin of the Society of Naval Architects of Korea
    • /
    • v.8 no.1
    • /
    • pp.95-102
    • /
    • 1971
  • Since the fuel oil of the bunker C grade, which is commonly burnt in the large marine diesel engine, causes the corrosive wear of cylinder liners and piston rings, a cylinder oil of high alkality is frequently used to prevent the wear. This practice, however, brings us an another problem to cause the abnormal wear. In this study the author made an investigation of the mechanism of the abnormal wear by the experiments surveying the influences of the alkality of a cylinder oil and the temperature of cylinder wall on the wear. The major results obtained from this study are as follows; A cylinder oil of low alkality is clearly effective for the preventation of the abnormal wear. Therefore, it is recommended that, prio to using a cylinder oil of high alkality, a cylinder oil of low alkality should be used until bringing an end to the initial wear. It is also observed that the abnormal wear depends largely on the temperature of the cylinder wall, that is, the higher the temperature goes up the severer the wear grows.

  • PDF