1. Fractal Analysis of Adhesion Particles on Tool Surface in Compression of Aluminum Strips [in Japanese], Yasushi KUROSAKI, Masahito MATSUI, Yasuhiro ASANO* and Kenichi MURAI: Journal of the JSTP, Vol.38, No. 433, pp. 153-158, 1997.
   
   Fractal geometry is applied to the analysis of particles adhered to the tool surface in simple compression of aluminum strips. The shape of particles is found to be self-similar, and their estimated fractal dimension depends on the surface topology of specimens, irrespective of the compression strain, tool surface finishing techniques and lubrication. The ratio of the total adhesion area to the apparent contact area increases with an increase in the fractal dimension of the tool surface. The cumulative frequency of each particle size (area) and the behavior of particle growth are also examined. A method for computer simulation of the adhesion feature is presented, and satisfactory images are constructed.
   
   
2. Fractal Characteristics of Free Surface Profiles of Metal Sheets under Equi-biaxial Tension [in Japanese], Yasushi KUROSAKI, Masahito MATSUI, Tomoyuki TAKAYAMA* and Akira NAKANISHI*: Transactions of the JSME, Ser. C, Vol. 63, No. 613, pp. 3265-3271, 1997.
   
   Free surface profiles of aluminum sheets under equi-biaxial tension are examined by employing three kinds of fractal analyses, i.e., the zeroset, power spectrum and box-counting method. With an increase in plastic strain, long-wavelength components of the surface profiles become dominant, and their fractal structure tends to be constant beyond a certain strain. It is found that the surface roughness and fractal dimensions depend on the equivalent strain, independent of the stress ratio. A method for simulating the surface roughening behavior is presented by utilizing the power spectrum method.
   
   
3. Fractal Characteristics of Adhesion Particles on Tool Surface in Metal Forming. Yasushi KUROSAKI, Masahito MATSUI and Toshihiro MORI*: Proceedings of the 1st International Conference on Tribology in Manufacturing Processes '97, Gifu, pp. 218-223, 1997.
   
   Characteristics of minute adhesion particles caused on the tool surface in compression of aluminum strips are investigated by introducing a concept from fractal geometry. Method for estimating fractal dimensions of the adhesion particles and such self-affine surfaces as those of the tool and specimen are presented. While the shape of aluminum adhesion particles is examined on the size level larger than one micron and is found to follow a statistically self-similar fractal, the size distribution of the particles in non-fractal. The fractal dimension of the particle shape is estimated as about 1.5, independent of the compressive strain and the initial topology of specimen surfaces. It is shown that this value is caused due to the compressive deformation of the specimen. Based on an assumption of self-similarity, the particle shape is extrapolated into a more minute size down to about thirty nanometers, and is compared with the experiment.

Abstracts of Books and Reviews

1. Evaluation of Viscosity and Phase Transition on Mineral Oils up to 1.9 GPa and 150 ℃ by DAC, Yuichi NAKAMURA, Ikuya FUJISHIRO*, and Shigeaki Nomura* : Abst. of Joint AIRAPT-16&HPCJ-38 Int. Conf. on High Pressure Science and Technology, Kyoto, 1, p.418, 1997.
   
   Viscosity and phase transition for several paraffinic and naphthenic mineral oils were obtained up to 1.9 GPa and 150℃ using a diamond-anvil cell. Phase transition temperature in heating was higher than that in cooling. In the results of viscosity measurements, the differences due to chemical components (paraffinic or naphthenic) and molar weight were found out. The difference due to treating process in oil manufacture (solvent extraction or hydrotreating) was found at 1.6 GPa.
   
   
2. Computer Simulation of Plastic Deformation in High Pressure Apparatus, Takeru NAKASHIMA*, Katsuyuki KAWATE*, Shuichi SATOH*, and Yuichi NAKAMURA : Abst. of Joint AIRAPT-16&HPCJ-38 Int. Conf. on High Pressure Science and Technology, Kyoto, 1, p.272, 1997.
   
   Pressure generation and sealing in high pressure apparatus is owing to plastic flow of gasket. Therefore numerical analysis of plastic deformation is expected to make the mechanism of pressure generation clear. Rigid plastic FEM is suitable to analyze the problems involving very large amounts of plastic deformation. This method was applied to the analysis of compression process in a diamond anvil cell. In comparison between experimental and analytical results, accuracy of the analysis was inspected. Simulation of  belt  type apparatus was also performed.
   
   
3. Measurements of Lubricants' Viscosity Under High Pressure Using DAC, Yuichi NAKAMURA : Abst. of JST Forums for Multidisciplinary Research "FRICTION - Basics of Tribology" pp.21-22, 1997.
   
   Friction (Traction) coefficient in elastohydrodynamic lubrication contacts depends on viscosity-pressure relation of lubricants. So thus, high pressure viscometry using a diamond-anvil cell (DAC) is introduced. By a falling sphere method in DAC, viscosity-pressure relation was obtained for traction oils up to 1.4 GPa and 155 ℃. Laser light scattering technique is applicable for DAC. Extremely high viscosity near glass transition point could be obtained by obtaining photon correlation function of scattered light. By measuring Brillouin light scattering, density was obtained. However, this density is dynamic one and of of GHz frequency. Differences can be observed between dynamic density and static one.