• 제목, 요약, 키워드: Wear

검색결과 6,894건 처리시간 0.041초

A Study on Statistical Classification of Wear Debris Morphology

  • Cho, Unchung
    • KSTLE International Journal
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    • v.2 no.1
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    • pp.35-39
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    • 2001
  • In this paper, statistical approach is undertaken to investigate the classification of wear debris which is the key function of objective assessment of wear debris morphology. Wear tests are run to produce various kinds of wear debris. The images of wear debris from wear tests are captured with image acquisition equipment. By thresholding, two-dimensional binary images of wear debris are made and, then, morphological parameters are used to quantify the images of debris. Parametric and nonparametric discriminant method are employed to classify wear debris into predefined wear conditions. It is demonstrated that classification accuracy of parametric and nonparametric discriminant method is similar. The selected use of morphological parameters by stepwise discriminant analysis can generally improve the classification accuracy of parametric and nonparametric discriminant method.

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Saffil/SiCp을 이용한 금속 복합재료의 상온 마모 거동 (Wear Behavior of Saffil/SiCp reinforced Metal Matrix Composites at the room temperature)

  • 조종인;한경섭
    • 한국복합재료학회:학술대회논문집
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    • pp.46-49
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    • 2003
  • Aluminum based metal matrix composites(MMCs) are well known for their high specific strength, stiffness and hardness. They are gaining further importance because of their high wear resistance. In this study, Al/Saffil-20%, Al/Saffil-5%/Al2O3(particle type)-15% and Al/Saffil-5%/SiC(particle type)-15% hybird MMCs' wear behavior were characterized by the pin-on-disk test under various normal load The superior wear resistance was exhibited at Al/Saffil-5%/SiC(particle type)-15% MMCs. And this MMCs' predominant wear mechanism is subsurface cracking in the low load wear regime. Others(Al/Saffil-20%, Al/Saffil-5%/Al2O3(particle type)-15%) showed the similar wear resistance with each other at the same test condition. In the low load & room temperature condition, the wear resistance was improved due to the high hardness of the ceramic reinforcements. As the test load increased, the wear properties were governed by the wear properties of matrix.

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인청동의 내마모성향상에 대한 연구 (A Study on the Improvement of the Wear Resistance of P-bronze)

  • 송건;권숙인;차영현
    • Tribology and Lubricants
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    • v.4 no.1
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    • pp.56-68
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    • 1988
  • The wear resistance of P-bronze which is widely used as worm gear material was investigated. In order 1o study the effect of additional elements on the wear resistance of Pbronze, the applied load and sliding time were selected as variables, and SCM4, were used as against metal. The addition of Fe improve wear resistance, for it precipities hard Fe$_3$ P phase and the work hardening coefficients are lowered due to decreasing solubility of P. When Fe is added in conventional P-bronze, the alloy is rather sliding than forming wear debris by frictional force during wear test. Experimental results indicated that the wear mechanisms for P-bronze are mainly consisted of abrasive wear due to Beilby layer forming mechanism and adhesive wear due to thermally activated wear mechanism. Moreover, the weight loss is decreased in accordance with increasing load and time. However the rate of wear loss is decreased as the sliding time is increased.

패턴인식기법을 이용한 공구마멸상태의 분류 (The Classification of Tool Wear States Using Pattern Recognition Technique)

  • 이종항;이상조
    • 대한기계학회논문집
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    • v.17 no.7
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    • pp.1783-1793
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    • 1993
  • Pattern recognition technique using fuzzy c-means algorithm and multilayer perceptron was applied to classify tool wear states in turning. The tool wear states were categorized into the three regions 'Initial', 'Normal', 'Severe' wear. The root mean square(RMS) value of acoustic emission(AE) and current signal was used for the classification of tool wear states. The simulation results showed that a fuzzy c-means algorithm was better than the conventional pattern recognition techniques for classifying ambiguous informations. And normalized RMS signal can provide good results for classifying tool wear. In addition, a fuzzy c-means algorithm(success rate for tool wear classification : 87%) is more efficient than the multilayer perceptron(success rate for tool wear classification : 70%).

퍼팅그린의 마모와 골프공의 구름에 미치는 골프화의 영향 (Effect of Different Golf Shoe treads on Wear and Ball Speed of Putting Green)

  • 심포룡;심규열
    • 아시안잔디학회지
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    • v.11 no.3
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    • pp.205-210
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    • 1997
  • The metal spikes evaluated in this study significantly affected more negative on the turf wear and ball speed of putting green than alternative plastic spikes. 1.The metal spikes caused the most amount of wear compared with plastic spikes, athletic shoes and mountain-climbing shoes. On the other hand, athletic shoes caused the least amount of wear. Plastic spikes caused wear more than athletic shoes, hut apparently wear less than metal spikes. The wear from metal spike repaired later than any other tread types. 2.The wear from all kinds of shoe treads in wetcondition green were higher than in dry-condition green and the wear from metal spikes was more severe compared with plastic spikes in both green condition. 3. Ball speed of heavy compaction area by metal spike was reduced about 9% compared with that of light compaction area, hecause metal spikes made many holes in the putting green surface. On the other hand, plastic spikes did not affect hall speed of heavy and light compaction area in the putting green. Key words: Metal spike, Plastic spike, Wear, Ball speed.

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판스프링을 사용한 마모실험에서 마찰계수와 마찰온도를 고려한 마모식의 개선 (Development of Wear Equation according to Friction Coefficient and Temperature using a Dual Leaf-Spring in the Sliding Test)

  • 김정현
    • 한국기계가공학회지
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    • v.5 no.1
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    • pp.19-26
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    • 2006
  • The wear behavior as the hardness of the sliding elements on the dry wear has been investigated using a dual leaf-spring. The materials of the specimens are used as ten kinds along their hardness. In this study, both upper and lower specimens have been used the same materials. Using experimental data, we figured the relationship between wear coefficient and friction coefficient, and the relationship between wear coefficient and friction temperature. Also we combined friction temperature and friction coefficient instead of wear coefficient. We substituted this into wear equation of Archard. The result had been derived a newly wear equation in using dual leaf-spring wear system.

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Development of Wear Model concerning the Depth Behaviour

  • 김형규;이영호
    • KSTLE International Journal
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    • v.6 no.1
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    • pp.1-7
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    • 2005
  • Wear model for predicting the vehaviour of a depth is considered in this paper. It is deduced from the energy and volume based wear models such as the Archard equation and the workrate model. A new parameter of the equivalent depth ($D_e$= wear volume /worn area) is considered for the wear model of a depth prediction. A concenpt of a dissipated shear energy density is accommodated for in the suggested models. It is found that $D_e$ can distinguish the worn area shape. A cubic of $D_e$($D_e^3$) gives a better linear regression with the volume than that of the maximmum depth $D_{max}e$($D_{max}^3$) does. Both $D_{max}$ and $D_e$ are used for the presently suggested depth-based wear model. As a result, a wear depth profile can be simulated by a model using $D_{max}$. Wear resistance from the concern of an overall depth can be identified by the wear coefficient of the model using $D_e$.

Relationship between Spring Shapes and the Ratio of wear Volume to the Worn Area in Nuclear Fuel Fretting

  • Lee, Young-Ho;Kim, Hyung-Kyu;Jung, Youn-Ho
    • KSTLE International Journal
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    • v.4 no.1
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    • pp.31-36
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    • 2003
  • Sliding and impact/sliding wear test in room temperature air and water were performed to evaluate the effect of spring shapes on the wear mechanism of a fuel rod. The main focus was to quantitatively compare the wear behavior of a fuel rod with different support springs (i.e. two concaves, a convex and a flat shape) using a ratio of wear volume to worn area (De)-The results indicated that the wear volumes at each spring condition were varied with the change of test environment and loading type. However, the relationship between the wear volume and worn area was determined by only spring shape even though the wear tests were carried out at different test conditions. From the above results, the optimized spring shape which has more wear-resistant could be determined using the analysis results of the relation between the variation of De and worn surface observations in each test condition.

A Study on the Variation of the Fretting Wear Mechanisms under Elastically Deformable Contacts

  • Lee, Young-Ho;Kim, Hyung-Kyu
    • KSTLE International Journal
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    • v.10 no.1_2
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    • pp.27-32
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    • 2009
  • In this study, fretting wear tests of nuclear fuel rods have been performed by using two kinds of spacer grid springs with a concave and a convex shape in room temperature dry and distilled water conditions. The objectives were to examine the variation of the wear mechanism with increasing fretting cycles and to evaluate the difference of the wear debris detachment behavior at each test environment. From the test results, the wear volume of each spring condition increased with increasing fretting cycles regardless of the test environments. However, the wear rate did not show a regular tendency and apparently changed with increasing fretting cycles. This is because the formation of the wear particle layer and/or the variation of the contact condition between the fuel rod and spring surfaces could affect a critical plastic deformation for detaching the wear debris. Based on the test results, the relationship between the wear behavior of each spring shape and test environment condition, and the variation of the surface characteristics are discussed in detail.

예측감시 시스템에 의한 드릴의 마멸검출에 관한 연구 (A Study on the Wear Detection of Drill State for Prediction Monitoring System)

  • 신형곤;김태영
    • 한국공작기계학회논문집
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    • v.11 no.2
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    • pp.103-111
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    • 2002
  • Out of all metal-cutting process, the hole-making process is the most widely used. It is estimated to be more than 30% of the total metal-cutting process. It is therefore desirable to monitor and detect drill wear during the hole-drilling process. One important aspect in controlling the drilling process is monitoring drill wear status. There are two systems, Basic system and Online system, to detect the drill wear. Basic system comprised of spindle rotational speed, feed rates, thrust torque and flank wear measured by tool microscope. Outline system comprised of spindle rotational speed feed rates, AE signal, flank wear area measured by computer vision, On-line monitoring system does not need to stop the process to inspect drill wear. Backpropagation neural networks (BPNs) were used for on-line detection of drill wear. The output was the drill wear state which was either usable or failure. This paper deals with an on-line drill wear monitoring system to fit the detection of the abnormal tool state.