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Volume 38 (2012)
- Issue 6 Pages 228-
- Issue 5 Pages 183-
- Issue 4 Pages 137-
- Issue 3 Pages 93-
- Issue 2 Pages 41-
- Issue 1 Pages 8-
Volume 38, Issue 3
Displaying 1-4 of 4 articles from this issue
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Research paper
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Tomohiro YOKOZEKI2012 Volume 38 Issue 3 Pages 93-100
Published: 2012
Released on J-STAGE: December 10, 2012
JOURNAL FREE ACCESSFoam-core sandwich beam specimens for fracture toughness measurement are designed based on the prediction method of steady-state crack location in foam-core sandwich beams using the crack deflection model developed previously. This paper derives the necessary condition that face sheet debonding grows along the interface between the face sheet and the core during the fracture toughness tests, and shows the recommended specimen thickness ratios for several testing methods. Finally, the physical meaning of the derived condition is explained, and the effect of residual thermal strains on the condition.View full abstractDownload PDF (952K) -
Limin BAO, Yuki KUROTA, Anchang XU, Kiyoshi KEMMOCHI2012 Volume 38 Issue 3 Pages 101-106
Published: 2012
Released on J-STAGE: December 10, 2012
JOURNAL FREE ACCESSIn recent years, studies on reducing the diameter of microcapsules for practical application to self-healing fiber reinforced plastics (FRP) have been conducted. This study clarifies the effects of the diameter and strength of the filler grain and filler volume fraction on the inter-laminar fracture toughness of FRP. The material used for reinforcement in this experiment was carbon fiber. Acrylic particles were used as filler; the mechanical properties were similar to those of microcapsules of self-healing FRP. The filler volume fraction was confirmed to affect the inter-laminar fracture toughness. The smaller grain diameters of the hollow particles and the higher Young's modulus of the filler would lead to the increased inter-laminar fracture toughness. High rigidity and small-grain diameter of microcapsules are considered to be appropriate repair agents for self-healing of carbon fiber reinforced plastics.View full abstractDownload PDF (1857K) -
Junji NODA, Yujiro TERASAKI, Yuji NITTA, Koichi GODA2012 Volume 38 Issue 3 Pages 107-115
Published: 2012
Released on J-STAGE: December 10, 2012
JOURNAL FREE ACCESSNowadays, natural fiber-reinforced green composites are increasingly being used in the industrial field. In general, the cross-sectional shape of natural fibers is not circular and show a large variation in their cross-sectional area. However, the tensile properties of natural fibers are often evaluated on the assumption of circle cross-sectional shape. Therefore, we proposed a new method to calculate the area of natural fibers by measuring their projection widths in order to estimate the proper tensile properties. Using this method, the effect of variation in cross-sectional area on tensile properties was investigated. Additionally, we proposed a novel strength distribution function with taking account of variation in cross-sectional area, based on Weibull distribution in order to estimate the proper Weibull parameters of natural fibers except for the cross-sectional area variation. Finally, the strength distribution function of natural fibers including the cross-sectional area variation was formulated.View full abstractDownload PDF (1665K) -
Takuma MURAKOSHI, Satoshi KOBAYASHI2012 Volume 38 Issue 3 Pages 116-126
Published: 2012
Released on J-STAGE: December 10, 2012
JOURNAL FREE ACCESSBioactive ceramics attracts much attentions as materials for the bone implants, because of their high biocompatibility. For example, hydroxyapatite (HA) has bone-bonding ability through the bone like apatite layer in body environment and β-tricalcium phosphate (β-TCP) has a high bioresorbability in body environment. In this study, HA/β-TCP composites with different content of β-TCP (0, 10, 20 and 30 wt%) were prepared by wet mixing of HA and β-TCP powders, compaction of the powder mixture and sintering. Bending strength of HA/β-TCP composites was measured before and after soaking in the simulated body fluid (SBF). The bioactivity of HA/β-TCP composites was also evaluated by soaking in SBF. To improve mechanical properties of HA/β-TCP composites, the effect of additive of SiO2 and MgO were also investigated. It was found that the several mechanical properties and ability of apatite formation decreased with β-TCP content. It was also found that the change in bending strength after soaking depended on its surface reaction in SBF and porosity. Additive of SiO2 did not improve mechanical properties and bioactivity. On the other hand, additive of MgO improved several mechanical properties, but lowered the bioactivity in SBF.View full abstractDownload PDF (5305K)
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