• Title, Summary, Keyword: Wear

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Measurement of Wear and Friction Coefficients for the Prediction of Fretting Wear (프레팅 마멸계수 및 마찰계수 측정에 관한 연구)

  • Cho, Yong Joo;Kim, Tae Wan
    • Tribology and Lubricants
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    • v.28 no.3
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    • pp.124-129
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    • 2012
  • The prediction of fretting wear is a significant issue for the design of contacting mechanical components such as flexible couplings and splines, jointed structures and so on. In our earlier study, we developed a numerical model to predict the fretting wear using boundary element method. The developed algorithm needs experimental fretting wear coefficients and friction coefficients between two moving materials to get more reliable results. In this study, therefore, we demonstrated the measurement method of the fretting wear coefficients and friction coefficients using disk on plate tribometer with piazo actuator and gap sensor. For four different material combinations, the fretting wear coefficients and friction coefficients are acquired through the fretting wear experiment and the analysis of the measured values. Thess results are useful to predict the quantative fretting wear rate in the developed algorithm.

Development of Wear Model concerning the Depth Behaviour

  • Kim, Hyung-Kyu;Lee, Young-Ho
    • 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 $D_e$.

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

  • Kim, Jung-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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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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The Relationship between a Wear Depth :and a Decrease of the Contacting Force in the Nuclear Fuel Fretting (핵연료봉 프레팅마멸에서 마멸깊이와 접촉하중 감소사이의 관계)

  • Lee Young-Ho;Kim Hyung-Kyu
    • Tribology and Lubricants
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    • v.22 no.1
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    • pp.8-13
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    • 2006
  • Sliding wear tests have been performed to evaluate the effect of normal load decrease on the wear depth of nuclear fuel rods in room temperature air. The objectives of this study are to quantitatively evaluate the supporting ability of spacer grid springs, to estimate the wear depth by using the contacting force decrease and to compare the wear behavior with increasing test cycles (up to $10^7$) at each spring condition. The result showed that the contacting load decrease depends on the spring shape and the applied slip amplitude. The estimated wear depth is smaller when compared with measured wear depth. Based on the test results, the wear mechanism, the role of wear debris layer and the spring shape effect were discussed.

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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Wear Mechanism of Tube Fretting Affected by Support Shapes

  • Kim, Hyung-Kyu;Lee, Young-Ho;Yoon, Kyung-Ho;Kang, Heung-Seok;Song, Kee-Nam;Ha, Jae-Wook
    • KSTLE International Journal
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    • v.3 no.1
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    • pp.68-73
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    • 2002
  • A fretting wear experiment in roam temperature air was performed to evaluate the wear mechanism of fuel rod using a fretting wear tester, which has been developed for experimental study, The main focus was to compare the wear behaviors of fuel rod against support springs with different contact contours (i.e. concave and convex). Wear volume, degree or surface hardening and adhesion tendency of wear particle were examined by the surface roughness tester. The result indicated that with a change of contact condition from contact force of 5 N to 0.1 mm gap, the wear volume of tube increased in the condition of concave spring, but slowly decreased in convex spring. From the results of SEM observation, wear mechanism of each test condition was also dependent on the spring shapes. The wear mechanism of each test condition in room temperature air is discussed.

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

  • 신형곤;김태영
    • Transactions of the Korean Society of Machine Tool Engineers
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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.

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

  • 조종인;한경섭
    • Proceedings of the Korean Society For Composite Materials Conference
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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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Effect of Different Golf Shoe treads on Wear and Ball Speed of Putting Green (퍼팅그린의 마모와 골프공의 구름에 미치는 골프화의 영향)

  • 심포룡;심규열
    • Asian Journal of Turfgrass Science
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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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Wear Behaviours of Dental Composite Resins Containing Prepolymerized Particle Fillers (1st Report) (有機複合필러를 包含하는 齒科用 콤포짓트 레진의 磨耗擧動(제1보))

  • 임정일;김교한;김석삼
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.124-130
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    • 1998
  • The wear characteristics and wear mechanisms of dental composite resins were investigated. Composite resins such as Metalii, Silux Plus, Heliomolar and Palfique Estelite were selected as specimens and contents of filler in specimens in order to analyze the effect of Prepolymerized Particle Fillers in friction and wear characteristics. Ball on flat wear tester was used for a wear test. Friction and wear tests are carried out at room temperature. The friction coefficient of Metafil was quite high relatively, and the wear resistance of Silux Plus and Palfique Estelite was better than that of Metafil and Hellomolar at the same experimental condition. The main wear mechanism is plastic flow and abrasive wear by crack propagation.

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