TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A

Journal Information
ISSN / EISSN : 0387-5008 / 1884-8338
Published by: Japan Society of Mechanical Engineers (10.1299)
Total articles ≅ 9,452
Filter:

Latest articles in this journal

Kousuke Zushida, , Hiroaki Yoshida, , , , Osamu Kuwazuru, Nobuhiro Yoshikawa
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 1079-1082; https://doi.org/10.1299/kikaia.79.1079

Abstract:
Open-cell porous copper (Cu) was fabricated by friction powder compaction (FPC) process, which requires no external heat sources. In this process, a mixture of Cu powder and sodium chloride (NaCl) powder as spacer particle was used as starting materials. The compacting of the powder mixture was conducted only by rotating tool plunged into the mixture. NaCl was removed by placing the sintered mixture in water, and pores were formed. Porous Cu with porosities of 60-80 % was successfully fabricated. In this study, a relationship between leaching time and removal of NaCl were investigated, and pore structures of obtained porous Cu were nondestructively observed by X-ray CT. In addition the compressive properties of obtained porous Cu were investigated.
Masatoshi Kuroda, Kazufumi Yasunaga, Masayuki Kamaya, Teruaki Yamada
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 1102-1106; https://doi.org/10.1299/kikaia.79.1102

Toshihiko Mouri, Yousuke Sugai, Makoto Shiranami, Fuminori Satoji, Mitsuo Arashida, Eiji Yuasa
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 1122-1126; https://doi.org/10.1299/kikaia.79.1122

Hideto Harada, Masaki Endo, , Hisaki Watari,
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 1147-1151; https://doi.org/10.1299/kikaia.79.1147

Abstract:
This study was aimed that Fabrication of Al/Mg clad material using a horizontal tandem twin roll caster. Magnesium is the lightest of structural metals combining high mechanical strength and low density. However, magnesium is low corrosion resistance. Aluminum alloys and magnesium alloys were fabricated as an Al/Mg composite using aluminum alloys as protective layers, improvement of the corrosion resistance of the magnesium alloys can be expected. In this study using twin roll casting process and downward melt drag process. And also in-line rolling process was used. A horizontal tandem twin roll caster consists of three kind of twin roll. AZ121 was cast by first twin roll, this is first strip. Downward melt drag process was used for casting of A1050, this is second strip. In case of narrow roll gap, AZ121 was melted by A1050 due to increased heat transfer coefficient. In this study, bonding could be better that cladding of aluminum on third twin roll would rather than cladding of aluminum on second twin roll. Thickness of clad strip was 5.5 mm, aluminum layer was 1.1 mm, magnesium layer was 4.3 mm. cladding ratio was 1.1 : 4.3. Mixed layer was 70-90μm in bonding region. Each diffuse layer of Al layer and Mg layer was 10 μm. Primary crystal size of Mg layer was 77μm at mixed layer region, 19μm at center region, 83μm at surface region.
Masanori Kikuchi
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 119-129; https://doi.org/10.1299/kikaia.79.119

Abstract:
It has been reported that stress corrosion cracking damaged in-core monitor housing, which occurred in weld heat-affected zone because of the existence of residual stress. So it is important to evaluate crack growth behavior with high accuracy. In this study, crack growth behavior in ICM Housing is estimated using S-version FEM (S-FEM), which allows generation of core finite model and the detailed mesh representing the crack independently. At First, axial, slant and circumferential surface crack are assumed at two locations where residual stress fields are different from each other. One is isotropic residual stress field, and another is circumferential residual stress field. It is shown that crack growth behaviors are different under different residual stress fields. Next, effect of the slit, which exists between ICM Housing and Pressure Vessel is evaluated. It is shown that the existences of slit increases stress intensity factors of growing surface crack. Finally S-FEM results are compared with those of Influence Function Method (IFM), which assumes that an elliptical crack shape exists in a plate. It is shown that IFM result is conservative than that of S-FEM.
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 177-187; https://doi.org/10.1299/kikaia.79.177

Abstract:
Rupture of atherosclerotic plaque in coronary artery causes serious results. Since heterogeneously distributed plaque may cause local stress concentration, the local strain in circumferential direction of the coronary artery with atherosclerosis was investigated. For eight specimens from four human atherosclerotic coronary arteries, four needles were stuck into each the specimen at equal intervals on their circumference. Specimens were pressurized and local circumferential length was calculated from movement of the needles observed from longitudinal direction. For each specimen, pressure strain elastic modulus Ep, stiffness parameter β, and incremental elastic modulus Einc were calculated. Local circumferential strain was calculated by referring to circumferential length at no-stress state. Total thickness Ttotal, plaque thickness Tplaque, medial and adventitial wall thickness Twall, and area fraction of plaque Aplaque were also measured in histological sections. Ep and β obtained in the present study were almost comparable to those of nonatherosclerotic human coronary arteries in previous studies. Local strains were different even in a circumference. The local strain at 80 mmHg ε80 correlated significantly with Twall (r = 0.48, p < 0.05), while ε80 had insignificant correlation with Tplaque, Ttotal, and Aplaque. Coefficient of variance of local Twall decreased with the increase in the pressure. These results indicate that mechanical properties of human atherosclerotic coronary arteries are heterogeneously distributed in circumferential direction, plaque has insignificant effect to their mechanical properties, and Twall becomes more uniform at physiological state than at no-stress state. These dada may be useful to simulate stress distribution in atherosclerotic coronary artery.
Yo Nozaka, Go Yamamoto, , Mamoru Omori, , Toshiyuki Hashida
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A, Volume 79, pp 764-768; https://doi.org/10.1299/kikaia.79.764

Abstract:
Alumina ceramics reinforced with multi-walled carbon nanotubes (MWCNTs) have been prepared by pressureless sintering. Resultant composites with the MWCNT contents up to 0.9 vol.% have shown relative density as high as 98%. In addition, with increasing the MWCNT contents up to 0.9 vol.%, bending strength and fracture toughness of the composites is found to be increase gradually, and the composite containing 0.9 vol.% MWCNTs have shown 18% and 32% simultaneous increases in bending strength (699.1 ± 46.1 MPa) and fracture toughness (5.33 ± 0.03 MPa·m1/2), respectively, compared with MWCNT-free alumina. Observations on the fracture surface and the tensile-loading experiments of MWCNTs using an in-situ SEM method with a nanomanipulator system demonstrate that the MWCNTs, rather than pulling out from the alumina matrix, tend to fail in so-called “clean break” manner. Theoretical calculations imply that tougher ceramics with MWCNT can be obtained by creating the appropriate interaction between the matrix and MWCNT: not too week but also not too strong to permit an adequate load transfer between the two parts and thus a consequent pulling out without breakage of MWCNT. For the design of tougher ceramics with MWCNTs, appropriate modification of fiber/matrix interface will be one of important factors.
Back to Top Top