Tribology Online
Online ISSN : 1881-2198
ISSN-L : 1881-218X
Volume 7, Issue 4
Displaying 1-11 of 11 articles from this issue
Editorial
  • Masabumi Masuko
    2012 Volume 7 Issue 4 Pages ii
    Published: October 15, 2012
    Released on J-STAGE: October 15, 2012
    JOURNAL FREE ACCESS
    The Japanese Society of Tribologists is pleased to announce that the 2011 Paper Award of Tribology Online was awarded to:

    “Analyses of the Adsorption Structures of Friction Modifiers by Means of Quantitative Structure-Property Relationship Method and Sum Frequency Generation Spectroscopy,” by Hiroaki Koshima, Hideki Kamano, Yoshio Hisaeda, Huijin Liu, Shen Ye, Vol. 5, No. 3 (2010) 165-172.

    and

    “The Effects of Hydrogen on Microstructural Change and Surface Originated Flaking in Rolling Contact Fatigue," by Hideyuki Uyama, Hiroki Yamada, Hideyuki Hidaka, Nobuaki Mitamura, Vol. 6, No. 2 (2011) 123-132.

    The Award Medals were presented to the authors by Dr. Yoshio Kumada, the former President of the Japanese Society of Tribologists, at the JAST Annual Meeting on 15th May, 2012.

    The Paper Award of Tribology Online is given annually to the author(s), either the JAST members or non-members, of the paper(s) judged as the best paper(s) published in Tribology Online (TROL) for the previous three years. All papers that appeared in TROL for the three years are reviewed by the JAST Awards Committee.
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Article
  • Masahito Ban, Naoya Hasegawa, Yuta Ueno, Hiroyuki Shinozaki, Takahumi ...
    2012 Volume 7 Issue 4 Pages 207-212
    Published: October 15, 2012
    Released on J-STAGE: October 15, 2012
    JOURNAL FREE ACCESS
    High-chromium white iron based weld overlay materials containing metal carbides were deposited, and the wear performances were evaluated using a dry sand/rubber wheel test according to American Society for Testing and Materials G65-04 standard. The test results demonstrated that the weld overlay materials showed relatively smaller mass losses, and had superior property of wear-resistance compared to conventional high-chromium white cast irons. The results of X-ray diffraction analysis, and optical and scanning electron microscopy observations revealed that the microstructures of the weld overlays were featured by the finer and harder carbides densely dispersed in the Fe-Cr-C system matrix compared with the high-chromium white cast irons. It was implied that the wear resistance was enhanced with an increase in the coverage rate of carbides to the matrix, and more densely dispersion of the finer and harder carbides provided mechanical support to depress the wear against asperities of the abrasion. Therefore, the weld overlays with densely dispersed finer and harder carbides in the matrix exhibited higher wear resistance.
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Short communication
  • Hiroshi Kinoshita, Masatoshi Kageyama, Aidil Azli Alias, Masahiro Fuji ...
    2012 Volume 7 Issue 4 Pages 213-217
    Published: October 31, 2012
    Released on J-STAGE: October 31, 2012
    JOURNAL FREE ACCESS
    Under micronewton loads, the high frictions on carbon nanotube (CNT) films (with a friction coefficient of 1.7) were decreased to less than the noise level (which was roughly a friction coefficient of 0.05) by applying an oscillating motion to a cantilever on which a sliding ball was glued. This large decrease of the friction coefficient has been never observed in previous studies. The applied oscillating motion caused the twisting and bending oscillations of the cantilever, which applied the lateral and normal oscillating forces to the sliding ball. The friction force decreased with increasing the oscillating amplitudes of the twisting and bending forces, and the frequency dependences of the friction force reduction was observed.
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Article
  • Koji Miyake, Takamasa Kume, Miki Nakano, Atsushi Korenaga, Koji Takiwa ...
    2012 Volume 7 Issue 4 Pages 218-224
    Published: October 31, 2012
    Released on J-STAGE: October 31, 2012
    JOURNAL FREE ACCESS
    Self-assembled monolayers (SAMs) of hexadecanethiol (HDT) and 16-mercaptohexadecanoic acid (MHDA) were used to vary the surface chemical properties, and oleic acid (OA) was used as a lubricant. A pin-on-disk tribometer equipped with Fourier transform IR (FT-IR) spectroscopy was used to evaluate the results of lubricants under various lubricating condition, and sum frequency generation (SFG) spectroscopy was used to obtain static information on the molecular structure of the boundary layer. The FT-IR results for the frictional properties of the SAMs lubricated with OA indicated that a transition from the hydrodynamic to mixed lubrication regime for the HDT-SAM occurred, however, the MHDA-SAM remained in the hydrodynamic lubrication regime under our experimental conditions. The FT-IR results indicate that in the hydrodynamic lubrication regime, the gauche/trans conformer ratio in the OA molecules decreased with the thinning of the oil film thickness for both HDT- and MHDA-SAMs. Upon the transition from the hydrodynamic to mixed lubrication regime, the gauche/trans conformer ratio increased. The SFG results for OA/HDT interface indicated that the HDT layer was only slightly influenced by the adsorption of OA, however, the adsorbed layer of the OA contained significant gauche defects. For the MHDA-SAM, OA molecules were adsorbed on the surface through hydrogen-bonding between their carboxyl groups. From the SFG and FT-IR results, the difference in the interaction between the types of SAMs and the OA is considered to affect the frictional properties of SAMs lubricated with OA.
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  • Koji Miyake, Junki Nishihara, Miki Nakano, Hiroki Mano, Shinya Sasaki, ...
    2012 Volume 7 Issue 4 Pages 225-233
    Published: October 31, 2012
    Released on J-STAGE: October 31, 2012
    JOURNAL FREE ACCESS
    The mechanisms of tribo-chemical reactions occurring between atmospheric gases and Cu, Fe, and Ni induced by friction were analyzed using XPS combined with a friction test system. For Ni, the friction coefficient measured in hydrogen was comparable to that measured in air. On the basis of results of the friction test performed by varying the partial pressure of hydrogen, the authors proposed a reaction model to describe the phenomena observed, and analyzed the role of the hydrogen and trace gases. The results indicated that water as well as hydrogen had an important role in the tribo-chemical reaction of Ni in a hydrogen gas environment.
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  • Norihito Mizote, Shin-ichi Kuroda
    2012 Volume 7 Issue 4 Pages 234-241
    Published: November 15, 2012
    Released on J-STAGE: November 15, 2012
    JOURNAL FREE ACCESS
    Hydrogenated amorphous carbon (a-C:H) films were deposited on rubber surface by plasma-enhanced chemical vapor deposition (CVD), using a non-equilibrium atmospheric pressure plasma torch. The effects of oxygen, in the deposition atmosphere, on the chemical and mechanical characteristics of a-C:H films were investigated. It was clarified that the amount of carbon atoms combined with oxygen atoms in the a-C:H films increased with the increase of the oxygen content in the deposition atmosphere. On the other hand, surface hardness decreased as the oxygen content increased. As a result, a very low frictional property of a-C:H films was achieved by CVD, using the non-equilibrium atmospheric pressure plasma torch with eliminating oxygen from the deposition atmosphere.
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  • Youhei Takagi, Yasunori Okano, Masatoshi Miyayaga, Nobuyuki Katayama
    2012 Volume 7 Issue 4 Pages 242-248
    Published: November 15, 2012
    Released on J-STAGE: November 15, 2012
    JOURNAL FREE ACCESS
    The effect of flow field on drag torque in a wet clutch was examined through numerical and physical experiments. Three-dimensional hydrodynamic numerical simulations were carried out, and the drag torque was measured experimentally for a single wet clutch pack. Two-phase flow induced by aeration was visualized in the experiment. The wet clutch consists of two parallel circular plates. The plate with one side covered with the frictional material was rotated. The radial or circumferential grooves were made on the rotating disk by dividing the frictional material. The lubrication oil was supplied from the axial center, and ejected into the surrounding open boundary. At low rotation speeds, the oil flow was of single-phase, and the drag torque was linearly proportional to the rotation speed since the wall shear stress increased monotonically. In the single-flow regime, the slope of drag torque curve was controlled with the clearance between the clutch plates. The drag torque reached a peak value at a certain rotation speed, and it decreased gradually after the peak because of aeration. The peak of drag torque was controlled by both the flow rate of supplied oil and the arrangement of grooves on the frictional material. It also was found that the smooth ejection of oil and the enhancement of aeration led to the drag torque reduction.
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  • Shunpei Kamitani, Kenji Nakanishi, Takafumi Matsushita, Samion Syahrul ...
    2012 Volume 7 Issue 4 Pages 249-257
    Published: November 15, 2012
    Released on J-STAGE: November 15, 2012
    JOURNAL FREE ACCESS
    A series of experiment to measure coefficient of friction under bulk plastic deformation in plane strain extrusion was carried out by using the apparatus in which a taper die and a plane plate tool were arranged in facing each other. The plane plate tool had detection part of the normal and frictional forces acting on the tool surface so that coefficient of friction could be measured. Conditions of frictional constraint on the surface of plane plate tool were changed by applying the lubricant with high viscosity or lubricant with low viscosity. While, lubricant applied to the other contact surfaces with billet such as the surfaces of taper die and sidewall was fixed to one kind. Billet was made of Aluminum (A1050-JIS) and the extrusion apparatus was made of SKD-11-JIS. Then, the values of coefficient of friction were measured and surface conditions of a billet were investigated on the plane plate tool side. Differences of the conditions of material flow and effective strain in whole area of deformation zone of a billet, which were affected with different frictional constraint on the surface of plane plate, were also investigated by carrying out the visioplasticy analysis.
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  • Syeda Tasneem Fathima, Neminath Bhujappa Naduvinamani, Shivakumar Hosa ...
    2012 Volume 7 Issue 4 Pages 258-266
    Published: November 30, 2012
    Released on J-STAGE: November 30, 2012
    JOURNAL FREE ACCESS
    The theoretical investigation made in this paper is to study the effect of transverse magnetic field on the performance characteristics of porous squeeze film lubrication between two rectangular plates with couplestress fluids. A most general modified Reynolds equation is derived using Stokes constitutive equations for couplestress fluids. The fluid in the film region and in the porous region has been modeled as a couplestress fluid. The analysis takes into account velocity slip at the porous interface using Beavers-Joseph criterion. A closed-form expression for pressure, load carrying capacity and squeeze film time are obtained. The results are presented for different operating parameters. It is observed that effect of couplestresses on the MHD squeeze film lubrication between porous rectangular plates is to increase the load carrying capacity significantly and to delay the time of approach as compared to the corresponding non-magnetic case and Newtonian case.
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  • Kenta Moriyasu, Tsuyoshi Nishiwaki, Takeshi Yamaguchi, Kazuo Hokkiriga ...
    2012 Volume 7 Issue 4 Pages 267-273
    Published: December 31, 2012
    Released on J-STAGE: December 31, 2012
    JOURNAL FREE ACCESS
    Relationship between shoe grip properties and distributions of traction coefficient, which is obtained from horizontal ground reaction force (GRF) divided by normal GRF, were experimentally investigated during running. The experiments were conducted with sensor shoes mounted miniature triaxial force sensors for the measurement of GRF distributions in contact area. In order to clarify influence of the grip property on GRF vectors distributions and traction coefficient distributions, two typed sensor shoes having different outer sole materials with high/low friction coefficients were developed. The results showed that traction coefficients for the low grip typed shoe decreased in the whole contact area at the end of stance phase during running. Furthermore, it was confirmed that contact area, directions of GRF vectors and traction coefficients locally changed depending on the grip property. As a result of relationship between distributions of propulsion force components at 19 local positions and stride length, production of propulsion force beneath toe area can efficiently acquire sufficient stride length to keep running speed.
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Editorial
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