GENERATION OF THREE DIMENSIONAL SUREACE TOPOGRAPHY USING NON-CAUSAL TWO DIMENSIONAL AR MODEL

UCHIDATE, M.,SHIMIZU, T.,IWABUCHI, A. ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 2000 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2000 No.-

In this paper, a generation procedure of 3-D surface topography data with specified parameters using non-causal 2-D AR(auto-regressive) model is described. The aim of this study is to establish generation procedure of 3-D surface topography for numerical simulations that deal with random surface topography directly and contribute to surface topography design. AR model can express surface topography as linear weighted summation of surface topography itself. Non-causal 2-D AR model is an advanced model of causal 2-D AR model used in previous researches. AR parameters are estimated by algorithm of least squares and height distribution of the surface generated by 2-D AR model is modified by Johnson transformation. Parameters of spectral property and height distribution are required to generate 3-D surface topography. Several sets of 3-D surface topography with specified parameters are generated with the proposed method and evaluated against some surface parameters.

BOLOGICAL AND QUALITY EVALUATIONS OF COATINGS AND THIN FILMS : COATING TRIBOLOGY RESEARCH IN NTL OF TSINGHUA UNIVERSIT

Jin, Yuansheng,Li, Shenghua,Peng, Haitao ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-

The investigations on tribological and quality evaluations of coatings and thin films which have been done over recent years in National Tribology Laboratory, Tsinghua University, were summarized. The main contents of the present overview include tribological evaluations of thermally sprayed ceramic and metallic coatings, tribological behaviors and mechanisms of coatings designed for high temperature lubrication and mechanisms of coatings designed for figh temperature lubrication, and quality evaluation of ceramic coatings and thin films by ultrasonics and micro-indentation.

ON THE TRIBOLOGY DESIGN

Xie,You-Bai ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-

Tribology design is discussed in a general sense to utilize new possibilities provided by the development of systems engineering of tribo-systems. The contents, target and characteristics of tribology design are discussed. It is emphasized that the tribology design can not be understood only as the design of tribo-pairs, as well as that tribology can not be understood only as friction plus wear plus lubrication. Results in the design of rotor-bearing-sealing-gear systems, thrust bearing systems, piston-rings-cylinder liner systems, active magnetic bearings and a smart tribo-material in China are introduced. A tribology Design Division and a division for building China Tribology Database are established in the Tribology Institution, CMES. The National Natural Science Foundation of China provides strong financial supports in such activities.

TRIBOLOGY AND ITS APPLICATIONS IN VIETNAM

TUAN NGUYEN ANH ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-

The short period of activity in the field of tribology in Vietnam gives some results which are truly scientific and industrial. Challenges in industrialization and modernization of Vietnam in traditional and new fields of technology require development and produtcion of more reliable, efficient machinery. Needs of tribology in mechanical engineering, materials engineering and other branchs provide the more wide field of application of tribology in the future.

Viet Tropical climate Its parameters Influence on the Wear of cast iron

Tuan, Nguyen Anh,Hung, Pham Van ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 2000 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2000 No.-

The influence of air environment on the wear of machine parts was investigated by comparing measure wear for friction pairs of different relative humidify. With changing humidity, the wear of cast iron materials has different results. However the relative humidity is not complete so that to study the effect of different factors of ambient air. The temperature and the air pollution are very important compositions of environment. So when to study the effect of atmosphere on the wear cast iron material, the experiments have performed in the conditions of changing humidity, temperature and beginning to be interested in the some polluted factors.

Fretting Wear Behavior of Zircaloy-4 tube in Light Water

Kim, T.H.,Kim, S.S. ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 2000 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2000 No.-

The fretting wear behavior of a Zircaloy-t tube, which is used as the fuel rod cladding in PWR nuclear power plants, was investigated experimentally in light water. A fretting wear tester was specifically designed for the fretting test. This study focused on the effects due to the combination of the normal load, slip amplitude and number of cycles as the main factors of fretting. The results of this study showed that the wear volume increased abruptly at a slip amplitude above 100㎛, which was defined as the critical slip amplitude of a Zicaloy-4 tube in light water, whereas below 160㎛ the wear volume decreased as the load increased at the same slip amplitude. A fretting map was drawn to identify the transition point with normal loads as well as with slip amplitudes.

NOVEL POLISHING METHOD USING MR LIQUIDS WITH STEEL NEEDLESS

Umehara, N. ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 2000 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2000 No.-

In order to polish complicated-shaped inner surfaces of molds, a new polishing method using Magnetic Rheological liquid (MR liquid) with steel needles was proposed. MR liquid with abrasives and steel needles generated polishing pressure. Oscillation motion was applied to MR liquid with electro-magnetic exciter during polishing. As results, introduction of steel needles to this method increased removal rate by 70 times. Obtained maximum removal rates for cemented carbide and tool steel is 1.6㎛/hour and 2.5 ㎛/hour, respectively. Removal rate is proportional to the inverse value of Vickers hardness of workpiece. So it is considered that material removal mechanism of this method is mechanical removal caused by plastic deformation. The sharp cone type magnetic pole provides largest removal rate of all. Increasing of coil current of the solenoid coil increases removal rate. It can be considered that magnetic field strength is governing factor for removal rate.

HYDRODYNAMIC THRUST BEARINGS WORKING IN SPECIAL CONDITIONS

TUAN, NGUYEN ANH,TURN, TRAN VIET ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 2000 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2000 No.-

This study modeled the real behavior of an hydrodynamic thrust bearing. A theory is developed to know the geometry of the contact and the start of the complete fluid film for each pad and at every time. Moreover the solution of the energy equation for the film and the heat transfer equation for the solids are used to calculated the temperature in every point of the thrust bearing. In the case of misalignment, the numerical procedure gives the working parameters for each pad. As the characteristics of the fluid going out one pad (leakage and temperature) influence the feeding conditions of the following pads, the lubricant recirculation at the inlet is taken into account. The results obtained for a misaligned hydrodynamic thrust bearing are presented. The influence of the degree of misalignment and the conditions of feeding is studied. The pressure field, the leakage, the temperature variations in the fluid film are presented. The operating characteristics of a thrust bearing are obtained by the simultaneous resolution of the Reynolds, the energy and heat transfer equations.

A Tribological Investigatin on Laser Textured and Mechanically Textured Disk of Computer Hard Disk Drive

Hwang, Pyung,Kim, Woo Seok,Kim, Jang Kyo ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-

A tribological investigation of ultra thin film magnetic storage disks, which have two different kinds of Start/Stop zone of laser, textured and mechanically textured disk has been performed before CSS test and after 15000cycles CSS test respectively. In order to measure surface height reduction after 15000cycles CSS test,atomic force microscope(AFM)HAS BEEN USED. the result of statistical analysis of surface roughness showed that bump height and height of mechanically textured zone were been reduced by about 4-7nm after 15000cycles CSS test. Continuous indentation stiffness test has been performed to measure the tribological properties such as elastic modulus and hardness of laser textured bump and mechanically textured zone for before CSS test and 15000cycles CSS test respectively. Friction characteristic of ultra multi thin film coatings and adhesion characteristic between coatings were evaluated by nano-scratch test using commercial Nano-indenter. Ramping normal load mode was been applied to this scratch thst from 0to 10mN for 500μm long scratch distance. If there is some damage on Bump, Mechanically Textured Zone after 15000 cycles CSS test due to sliding contact at interface between head and disk, this is the major problem of computer hard disk drive in recent years .Auger electron spectroscope(AES)and time of flight secondary ion mass spectroscope (TOF-SIMS)can detect chemical component on bump, mechanically textured zone, the result showed that there was not big damage on Start/Stop Zone after 15000cycles CSS Test. In this paper, through performance of surface analysis and measurement of tribological properties of two kinds of start/stop zone before/after CSS test, tribological characteristic, wear and failure mechanism at interface between head and disk can be understood.

NECESSATY OF QUALITATIVE TRIBOSYSTEMS DEVELOPMENT FOR OUTER SPACE

Drozdov, Yuri. N ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-

It is stated the particularity of friction units operation in deep space: absence of the oxidising atmosphere, the vacuum presence, the sublimation of materials elements, heightened evaporability of lubricants, the heat density, high gradient of temperatures, the space radiation, the zero gravity, the micrometeorites influence, the effect of vibratory and impact loads at start and landing stages of space vehicles, the complication of the liquid oils application. What with comparatively limited energetic resources of autonomous space systems, seeking for the minimisation of mass and dimensional characteristics, the obstructivity of the repair(the maintenance) advisable at the design stage to determine expectable energy losses, the reliability of tribological systems. Inapprehension of the problem relevance leads to breakdowns and catastrophes in space.