A split shaft device is commonly used to measure the radial force of lip seals. The radial force measured with this device includes some inevitable error. This error is caused by the fact that the split shafts cannot maintain a perfect circle when the interference becomes larger or smaller than some initial interference. In this study, a theoretical model for the calculation of the radial contact force has been carried out, and an explicit equation for the measurement error as a function of the initial interference and the interference to be measured has been obtained. The error when the interference is small is not dependent upon the material properties and the shape of the lip seal, but rather upon the amplitude of the initial interference and the interference to be measured. When the interference is larger or smaller than the initial interference, the measured contact force is always underestimated or overestimated.

The life of rolling elements depends on various factors such as operating conditions and material properties. In this work, the effect of microstructure on the rolling behavior is investigated. Specially, the deformations in the substrate regions before and after rolling are compared. It is found that rolling action causes severe flow of material in the direction opposite to the rolling direction in the case of dry rolling direction. With lubrication, the deformation is more severe at the subsurface region rather than at the surface.

This paper reports on theoretical study of the pressure overshoot in the delivery ports and pressure rising within balanced type vane pump. Pressure overshoot occur due to the accelerated fluid through the notch, so, result in pressure ripple, flow ripple, and noise. For calculating the pressure rising and fluctuations of pressure, we have modeled mathematically used continuity equation based on compressibility and momentum equation considered fluid inertia in the notch, and analyzed simultaneously. As a results of analysis, we have found oscillation of pressure and compression chamber pressure depend on the rotational speeds, bulk modulus of working fluid, notches, number of vane and camring. Using the model, notches have been shown to be important design factor in relaxing the rapid pressure rising and reducing the amplitudes of pressure overshoot.

This paper describes an empherical equation which is to predict the engine condition of the supersonic aircraft. The equation, which is a function of running time of engine and engine oil, is derived from the trend analysis of JOAP data. Qualitative analysis is carried out to make up for the weak points in the current JOAP system. Also wear debris collected from the abnormal engine is analyzed by EDS to detect the damaged parts of engine.

Films and coatings are used for an enormous and diverse set of applications including mechanical, electronic and optical devices, protection at high temperature, cutting tools enhancement and automotive use. Many of these applications require the various properties associated with inorganic and metallic / non-metallic materials; i.e., with ceramics. Therefore, a large number of coatings have been developed and used for a long time in the various fields, especially in mechanical one. As one of the mutual surface actions, the problems of contact stresses are complex. The relationship between load and stress are nonlinear. Besides, the material is often apt to deform plastically under low load. However, analytical solutions exist only for some simple problems. If a material has a complicated shape or inhomogeneous properties, numerical method must be used. In this paper, the analysis of the contact stress of the coating layer was solved, using the finite element method.

The modern orthopaedics frequently uses the total hip replacement in the artificial hip joint. The wear in this joint requires the re-replacement of the hip joint beacuse it is under the severe load and friction conditions. To solve these problems the previous studies have been mainly focused on the development of the new materials. The research of new material, however, needs much time and effort since it should be experimented for its bio-compatibility, friction, and wear characteristics. To reduce the work, in this study, the finite element analysis is applied to find the new combination of the materials in the total hip replacement which has the excellent contact characteristics. The finite element uses MARC and the 5-node aximetric element. The results show that in case of acetabulum UHMWP has good characteristics, in femoral head, the $Al_2O_3$, and in stem, Ti6Al4V.

The dynamic characteristics of externally pressurized journal bearing have been studied theoretically. The Reynolds' equation has been solved by FDM, and the dynamic coefficients have been calculated by using perturbation method. The bearing is compensated by orifice or double-pad diaphragm control valve. The effects of diaphragm initial gap and stiffness are considered. As the results of analysis, it is shown that a control valve has better performance than orifice.

An experimental study of the characteristics of the repulsiveytype magnetic bearing using high Tc superconductor is presented. In field cooling superconductor has the position-stability due to a flux pinning effect and the strong damping due to hysterisis, while in zero field cooling it has the only strong repulsive force due to Meissner effect. Lift force in superconducting levitation has a hysterisis characteristics, and it is the dissipation of energy, the mechanism of damping. As the relative linear velocity between a magnet and a superconductor increases, the area of the hysterisis loop becomes smaller. It means the decrease of damping. In field cooling, the static stiffness is very nonlinear in smaller than initial gap, but almost linear in larger than initial gap.

The shotpeening treatment were conducted for improving the strength of rolling contact fatigue of machine element like a gear. This paper was undertaken to analyze the influence of shotpeening treatment for inner race of ball bearing on the roiling contact fatigue. Shotpeening treatment were applied to the full hardened and the carbonitrided bearing. And the rolling contact fatigue life test and X-ray diffraction test were carried out. The results of this study showed that the fatigue life of ball bearing in the clean and the contaminated oil could be improved by shotpeening treatment. This effect was found to be more pronounced to the full hardened bearing.