• Title, Summary, Keyword: Wear

Search Result 6,910, Processing Time 0.052 seconds

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
    • /
    • v.4 no.1
    • /
    • pp.31-36
    • /
    • 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
    • /
    • v.10 no.1_2
    • /
    • pp.27-32
    • /
    • 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.

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
    • /
    • v.11 no.2
    • /
    • pp.103-111
    • /
    • 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.

A Fundamental Study for the Sliding Wear Characteristics of the Crane Sheave Against a Rope Wire (크레인시브와 로프소선간의 미끄럼 마멸특성에 관한 기초연구)

  • Ryu, Jung-Buk;Chae, Young-Hun;Kim, Seock-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.27 no.11
    • /
    • pp.1873-1880
    • /
    • 2003
  • The sliding wear characteristics of the crane sheave were investigated using a pin on disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

A study on automatic wear debris recognition by using particle feature extraction (입자 유형별 형상추출에 의한 마모입자 자동인식에 관한 연구)

  • ;;;Grigoriev, A.Y.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.314-320
    • /
    • 1998
  • Wear debris morphology is closely related to the wear mode and mechanism occured. Image recognition of wear debris is, therefore, a powerful tool in wear monitoring. But it has usually required expert's experience and the results could be too subjective. Development of automatic tools for wear debris recognition is needed to solve this problem. In this work, an algorithm for automatic wear debris recognition was suggested and implemented by PC base software. The presented method defined a characteristic 3-dimensional feature space where typical types of wear debris were separately located by the knowledge-based system and compared the similarity of object wear debris concerned. The 3-dimensional feature space was obtained from multiple feature vectors by using a multi-dimensional scaling technique. The results showed that the presented automatic wear debris recognition was satisfactory in many cases application.

  • PDF

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
    • /
    • /
    • pp.124-130
    • /
    • 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.

  • PDF

Rolling Wear Mechanism of Ceramics by SEM Observation (SEM 관찰에 의한 세라믹의 구름마모기구)

  • Kim, Seock-Sam;Kato, Kohji;Hokkirigawa, Kazuo
    • Tribology and Lubricants
    • /
    • v.5 no.1
    • /
    • pp.36-43
    • /
    • 1989
  • Scanning electron microscopic observations were carried out on the worn surface and the wear debris of ceramic materials to investigate the wear mechanism of those in dry rolling contact. It was found from the scanning electron microscopic observations that the wear in ceramic materials is related to brittle fracture and has two types of wear mechanisms, small scale wear and larvae scare wear. Plate-like wear debris were created from the initial surface cracks and defects. The small scale wear was related to real contact area and large scale wear was related to HertzJan contact area. A wear model was proposed on the basis of scanning electron microscopic observations.

A Study on Statistical Classification of Wear Debris Morphology

  • Cho, Unchung
    • KSTLE International Journal
    • /
    • v.2 no.1
    • /
    • pp.35-39
    • /
    • 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.

  • PDF

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
    • /
    • /
    • pp.46-49
    • /
    • 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.

  • PDF

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

  • Song, Kun;Kwun, Sook-In;Cha, Young-Hyun
    • Tribology and Lubricants
    • /
    • v.4 no.1
    • /
    • pp.56-68
    • /
    • 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.