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FEM Analysis on Elastic-Plastic Deformation of Perforated Sheets
Abe, Takeji,Nakayama, Yasuhide,Kodama, Akira,Nagaki, Shigeru 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.3
The influence of distribution and growth of voids on macroscopic mechanical properties are important issues in the ductile fracture of metals. In the present paper, we consider perforated sheets with regularly distributed holes as a simple model for void containg materials. Elastic-Plastic deformation of perforated sheet, where circular holes are distributed regularly, was analyzed numerically under the plane stress condition by means of finite element method introducing the periodic boundary conditions. It is shown that the deformation behavior depends highly on the distribution and arrangement of holes. This results in anisotropy of yield stresses of perforated sheets, which is related to the stress concentration near the holes. It is also shown that the plastic region in perforated sheets does not develop simply in the direction to adjacent holes.
Tonna Ryutaro,Sasaki Takayuki,Kodama Yuji,Kobayashi Taishi,Akiyama Daisuke,Kirishima Akira,Sato Nobuaki,Kumagai Yuta,Kusaka Ryoji,Watanabe Masayuki 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4
Simulated debris was synthesized using UO2, Zr, and stainless steel and a heat treatment method under inert or oxidizing conditions. The primary U solid phase of the debris synthesized at 1473 K under inert conditions was UO2, whereas a (U, Zr)O2 solid solution formed at 1873 K. Under oxidizing conditions, a mixture of U3O8 and (Fe, Cr)UO4 phases formed at 1473 K, whereas a (U, Zr)O2+x solid solution formed at 1873 K. The leaching behavior of the fission products from the simulated debris was evaluated using two methods: the irradiation method, for which fission products were produced via neutron irradiation, and the doping method, for which trace amounts of non-radioactive elements were doped into the debris. The dissolution behavior of U depended on the properties of the debris and aqueous solution for immersion. Cs, Sr, and Ba leached out regardless of the primary solid phases. The leaching of high-valence Eu and Ru ions was suppressed, possibly owing to their solid-solution reaction with or incorporation into the uranium compounds of the simulated debris.
Optical Technique to Measure Five-Degree-of-Freedom Error Motions for a High-Speed Microspindle
Hiroshi Murakami1,Norio Kawagoishi,Eiji Kondo,Akira Kodama 한국정밀공학회 2010 International Journal of Precision Engineering and Vol. No.
We present an optical technique to measure five-degree-of-freedom error motions of a high-speed microspindle. The measurement system consists of a rod lens, a ball lens, four divided laser beams, and multiple divided photodiodes. When the spindle rotates with its concomitant rotation errors, the rod and ball lenses, which are mounted to the chuck of the spindle, are displaced, and this displacement is measured using an optical technique. For this study, we decide the design parameters of the optical system using ray tracing, fabricate a prototype of the measurement system, and evaluate it experimentally. The results show that the measurement system has a resolution of 5 nm and can be used to evaluate high-speed microspindle rotation errors.