材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
53 巻 , 9 号
選択された号の論文の18件中1~18を表示しています
  • 沖本 邦郎, 岩本 和久, 加藤 欽之
    2004 年 53 巻 9 号 p. 938-943
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Granulated powder produced from fine powder for the MIM (metal powder injection molding) process was used to fabricate a composite part consisting of Fe-47Ni permalloy and SUS410L ferritic stainless steel. Green compacts of disk and ring shapes were separately fabricated and assembled into a unit. The Unit was sintered at 985°C-1255°C for 1h in vacuum. The use of the granulated powder increased the joint strength. In case of fine powder, cracking was observed frequently in the outer ring after sintering, but the generation of cracks did not occur in the granulated powder. The joint strength was discussed in terms of the inner disk and outer ring materials and the clearance between them. The joint strength of the composite prepared with a combination of an inner disk of SUS410L stainless steel and an outer ring of Fe-47Ni permalloy (B type) was superior to that of the composite fabricated with the opposite combination (A type). This is reverse to the result in using the fine powder for the MIM. It is due to the fact that difference (Δεθ) in the change in diameter between the outer ring and the inner disk of the granulated powder compacts by sintering is smaller than that of the fine powder compact. It can be concluded that, in the granulated powder, the effect of diffusion during sintering shrinkage on the joint strength is relatively lowered compared to the fine powder for MIM and the effect of thermal expansion of the inner disk is enlarged on the contrary.
  • オステオンの層数と密度が構造強化に及ぼす影響
    片山 傳生, 山本 英毅, 徳田 周二
    2004 年 53 巻 9 号 p. 944-949
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of this study is to develop a new material by mimetics of the load support mechanism of bones. Laminated cylindrical structures (osteons) and laminated plate ones (plexiform bones) by collagen fibers are distributed in the shaft part of long bones. Small columns made of bovine femora were statically compressed. Only osteonal bone specimens had the elastic region over 0.5% in strain and the progress of crack avoiding osteons was observed in the cross section. When the layer number of osteon was smaller and the volume fraction was higher, the stiffness and the maximum stress of specimens were higher. In this study, we investigated the load support of combined structures of Filament Wound (FW) composite cylinders by considering the layer number and the volume fraction of osteon. In even single FW cylinder, the stiffness and the maximum stress became larger when increasing the layer number in the case of the larger fiber winding angle against cylindrical axis. In the combined structure of 4 FW cylinders, it was shown that the force interfering in cylinders by the difference of the volume fraction influenced the structural reinforcing.
  • 東藤 貢, 米田 真介, 新川 和夫
    2004 年 53 巻 9 号 p. 950-955
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Glass microballoon filled epoxy resin (GM/EP) has widely been used as an encapsulant for aerospace engineering; however, distributed GM particles generally reduce the toughness of the matrix epoxy resin. It is wellknown that the toughness of epoxy resins can be improved by blending CTBN rubber, therefore, in the present study, CTBN modification of GM/EP was attempted to improve its toughness. GM filled neat epoxy 828 (828G) and GM filled rubber-toughened 828 (828RG) were fabricated, and fracture toughness, bending strength and fracture absorbed energy were evaluated at quasi-static and impact loading-rates to assess the effects of rubber modification on these fracture properties. The results exhibited that the fracture properties were dramatically improved by rubber modification. SEM observation of fracture surfaces was also performed to characterize fracture mechanism, and it was found that interfacial debonding and shear band formation play important roles in the toughening of GM/EP by rubber modification.
  • 倪 慶清, 傅 雅琴, 岩本 正治
    2004 年 53 巻 9 号 p. 956-961
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    The properties of organic/inorganic nanocomposites are determined by the performance of an inorganic particle and organic matrix. Thus, it is important to clarify the mechanical properties of inorganic particles in nanocomposites. However, since the size of a particle is very small even at a nano order, it is difficult to measure their properties. In present paper, PMMA/Silica nanocomposites were innovated by in-situ polymerization. In order to calculate the modulus of elasticity of inorganic particles in the organic/inorganic nanocomposites, the inverse analysis of equivalent inclusion method (EIM) was proposed. Using this numerical analysis, the modulus of elasticity for the silica particles was calculated. It was found that the modulus of elasticity was kept almost unchanged within about 8% of the silica particle volume fraction and it was increased greatly when its particle size became to be a nano order. This result was reasonable and has also been confirmed and compared with the three phase model. With the results obtained, it is also shown that the proposed method is effective for the prediction of the modulus of elasticity for inorganic particles in nanocomposites.
  • 小曲 一臣, 轟 章, 島村 佳伸, 小林 英男
    2004 年 53 巻 9 号 p. 962-966
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    For a cryogenic tank of a next generation reusable launching vehicle, a laminated composite tank is one of the key technologies. For the fuel tank made from laminated carbon fiber reinforced composites, matrix cracking is a significant problem that may cause leak of fuel. In the present paper, electrical resistance change method is adopted to detect the matrix cracking of the laminated composites. Tension load in fiber direction causes electric resistance increase, and fiber breakages also cause the electric resistance increase of the CFRP laminates. Moreover, matrix cracking must be detected before charging fuel in the tank. In order to solve these problems, residual electrical resistance under complete unloading condition is measured here. Experimental investigations were performed using cross-ply laminates, and as a result, it can be revealed that the residual electrical resistance shows rapid increase after matrix cracking. FEM analyses were also performed to clarify the mechanism of the increase of electrical resistance due to matrix cracking. Small electrical current exits in the middle 90° ply, and the matrix crack impedes the current. This causes the linear increase of electrical resistance with the number of matrix cracking.
  • 千葉 良一, 菅野 良弘
    2004 年 53 巻 9 号 p. 967-973
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    The statistics of the temperature and thermal stress are quantitatively obtained by Monte Carlo simulation method for functionally graded material plates (FGM plates) with uncertainties in the thermal conductivity and coefficient of linear thermal expanssion and with arbitrary nonhomogeneous thermal and mechanical properties through the thickness of plate. The stochastic temperature and thermal stress fields are analyzed by approximating the FGM plates as multilayered plates with random thermal conductivity and coefficient of linear thermal expanssion in each layer. Autocorrelation coefficients of the random properties and crosscorrelation coefficients between the random properties are expressed in exponential function forms as homogeneous Markov random field of discrete coordinate. Numerical calculations are carried out for FGM plates composed of PSZ and SUS304, which have two different variability of random properties. The effects of the step-wise change in material composition, boundary condition and correlation coefficients on the standard deviations of temperature and thermal stress are discussed.
  • 兼平 真悟, 桐原 聡秀, 宮本 欽生, 迫田 和彰, 武田 三男
    2004 年 53 巻 9 号 p. 975-980
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    A three-dimensional photonic crystal with a diamond structure made of epoxy lattices incorporating TiO2-SiO2 composite ceramics particles were fabricated by stereolithography. The transmission spectra of microwaves with TE10 mode through the photonic crystal showed the existence of a complete photonic band gap in the frequency range of 14.3-15.8GHz. An air cavity defect with a rectangular shape was introduced into the photonic crystal by removing three or five unit cells aligned in the diamond structure. The transmission amplitude of microwave through each defect structure showed the existence of a resonant mode inside the photonic band gap. A planar waveguide with the diamond structure, which contains an air cavity layer, was also formed by using stereolithography. It showed a transmission of a resonant mode at 15.4GHz.
  • 鈴木 拓雄, 佐々木 徹, 平島 健一
    2004 年 53 巻 9 号 p. 981-986
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this paper, two-dimensional electro elastic analysis are performed for isotropic piezoelectric materials containing multilayered elliptical inclusion under anit-plane mechanical and in-plane electrical loads at infinity. It is assumed that the most inner inclusion has a slit crack or a rigid line inhomogeneity and the former slit crack is impermeable to electric fields. The problem of confocal multi-layered elliptical inclusion with perfect and/or imperfect interphases are considered Under the four cases of combined electric and mechanical loadings, various intensity (singularity) factors of Mode III are treated in this paper. General solutions are provided in terms of complex functions and several numerical examples by graphical representation.
  • 清水 憲一, 鳥居 太始之, 越智 宏臣
    2004 年 53 巻 9 号 p. 987-993
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Using a fatigue testing method by which fatigue cracks can be initiated and propagated in a film adhered to cover an circular through-hole in a base plate subjected to pull-pull cyclic loads, annealed rolled commercially-pure iron films of 100μm thickness were fatigued under constant stress amplitudes with a stress ratio of R=0. In order to discuss correlation between fatigue crack propagation and change of crystal orientation, crystal orientation on the surface of the film materials was measured before and after fatigue testing. The crystallographic information of these films was analyzed using the Electron Back-scatter Diffraction (EBSD) system. As a result, the fatigue crack propagated not only along the boundary of crystal grains but also in a crystal grain and it was found that the scatter of crystal orientation around the fatigue crack on the films became larger after the crack initiation and propagation than before fatigue testing.
  • 安宅 健, 奥本 良博
    2004 年 53 巻 9 号 p. 994-998
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to examine the effect of grain boundaries on bending cyclic behavior, aluminum bicrystals and their component crystals (A and B) were investigated under the constant strain amplitude of 0.13% at room temperature. Bending moments of the bicrystals were compared with mixture models which were calculated by joining results of component single crystals. The cyclic saturation moments at 1000 cycles of the bicrystals were higher than those of the calculated ones. It was suggested that the existence of the grain boundaries possibly shortened the fatigue lives in aluminum bicrystals.
  • 村澤 剛, 光真坊 誠, 米山 聡, 佐久間 俊雄, 隆 雅久
    2004 年 53 巻 9 号 p. 999-1005
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Shape memory alloy (SMA) has been paid attention as smart material revealing shape recovery by heating. Many researchers have investigated its basic properties and applications. However, many problems have existed in usage of SMA such as change of properties (transformation temperature, Young's modulus) by process of fabrication, shape memory treatment, condition of phase and so on. Therefore, it has been pointing in recent years that expressing these phenomena using conventional constitutive relation of SMA has been difficult. In the present study, phenomena needed to construct novel constitutive relation of SMA, such as nucleation and propagation of phase transformation and so on, were measured using digital image correlation method. Here, tensile loading and unloading tests were performed for NiTi alloy plate in two temperature regions where the SMA shows the shape memory effect (26°C) and pseudoelasticity (60°C). The obtained results were as follows; (1) The propagation of the phase transformation during the stress-induced martensitic transformation and austenite transformation progressed from the both ends to the center of the specimen. (2) Staying phenomena of deformation was confirmed at nucleation point of phase transformation. Deformation behavior of SMA can be classified broadly into three categories, such as “Nucleation of phase transformation”, “Process between nucleation and propagation” and “Propagation of phase transformation”. (3) The transformation had a fixed angle along the longitudinal direction of the specimen, propagating from the both ends to the center of the specimen.
  • 桂 千代, 鈴木 拓雄, 平島 健一
    2004 年 53 巻 9 号 p. 1006-1011
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this paper, the theory of initial stress measurement based on stress release technique for vscoelastic rock with circular solid inclusion cell (SI-cell) is described. And this theory not only uses the complex variable method and the correspondence principle between elasticity and viscoelasticity, but also considers a bonding interface between a rock and SI-cell. In addition, the problem under pure 3-dimensional loadings can be solved as semi-3-dimensional analyses. Several examples are shown by graphical results.
  • 淡路 英夫, 崔 成〓, 陳 春紅, 岸 伸幸
    2004 年 53 巻 9 号 p. 1012-1018
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Our previous technique for estimating critical sizes of the frontal process zone (FPZ) in ceramics was improved using exact solutions of stress distributions around crack and elliptical hole tips in an infinite plate for calculating local fracture stresses. The local fracture stress was calculated at the characteristic distance from the notch tip on the basis of a local fracture criterion. A three-point flexure test for alumina was carried out using V-notched specimens, and a formula for the relation between the strength and the notch depth including the short notch depth region was successfully established. The critical FPZ size of alumina was estimated from the fracture toughness and strength of the material. The critical FPZ sizes for alumina-based nanocomposites were also estimated. A concept of material design for toughened ceramics was discussed on the basis of these data. It was proved that there was a linear relationship between the fracture toughness and the product of strength and square-root of the FPZ size for these materials. This relation suggests that both the strength and the critical FPZ size must be increased to enhance the fracture toughness of ceramics.
  • 川村 昌志, 尾角 英毅, 西尾 光司, 鈴木 賢治
    2004 年 53 巻 9 号 p. 1019-1023
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    An investigation was carried out into the effect of the interface roughness between the metallic bond coat and the ceramic topcoat on internal stresses in a thermal sprayed ceramic thermal barrier coating (TBC). To evaluate the effect of the interface roughness on the residual stress in the top coat, the specimens with two kinds of roughness were prepared. The interface roughness oh the bond coat was Ra=5.8μm for the rough type specimen, and Ra=3.5μm for the smooth type one. The in-plane stresses of the specimens were measured with laboratory X-rays. The inplane stresses for the both of the rough and smooth specimens were about 60MPa and independent of the roughness of the bond coat. Using high energy X-ray, the stress of the rough specimen was compressive and the stress of smooth specimen was tensile. This tendency is different from the result measured by laboratory X-ray. This difference in the stress value is coursed by the out-of-plane stress. These stresses in the topcoat were estimated by the hybrid method, that is to estimate out-of-plane stress using laboratory X-rays and high-energy synchrotron X-rays. As a result, the larger the roughness of the bond coat became the larger out-of-plane-stress become.
  • 荒井 正行, 岩田 宇一, 水津 竜夫, 谷 和美
    2004 年 53 巻 9 号 p. 1024-1029
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Recently, metal temperature of combustor and blade in a land-based gas turbine is increasing with inlet gas temperature, in order to improve the thermal efficiency. Thus, thermal barrier coating (TBC) technology is applied to the surface of these hot parts for reducing the metal temperature. Advanced TBC materials and its processing technology such as functionally graded TBC and electron beam deposited TBC had been developed for these demands. But, application of these developed TBCs to the actual turbine blade was found to be difficult, because of a high cost of the processing machine and so on.
    In this study, advanced TBC with vertical crack in the top coating layer (vertical-crack induced TBC) was tried to fabricate by using a combination of conventional thermal spray technology and the special heat treatment. Then, the material properties, such as thermal stress variation of the TBC during thermal cycling, bonding strength between the top coating and bond coating and the interface oxidation process, were examined. Through some material evaluations for the vertical-crack induced TBC, it was found that the thermal stress in the top coating, which is caused during thermal cycling, is very lower than one of a conventional TBC. The bonding strength of the vertical-crack induced TBC is also higher, and then its TBC interface oxidation thickness is very thin. The vertical-crack induced TBC, which was evaluated here, was found to be superior to the conventional TBC.
  • 向井 竜二, 巨 東英, 皆川 宣明, 森井 幸生, 盛合 敦
    2004 年 53 巻 9 号 p. 1030-1035
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
    Neutron diffraction method is employed to measure the residual stress inside of quenched steel. To determine the residual stress, it is necessary to know the non-distortion lattice spacing and elastic constant of the material depending on gradient distribution of microstructure and carbon content. In this paper, metallo-thermo-mechanical simulation by finite element method is performed to estimate the distribution of martensite phase and carbon content. Non-distortion lattice spacing, Young's modulus and Poisson's ratio were measured in order to measure the residual stress of test piece of quenching. These values are decided by the distribution of carbon content and martensite phase. After that, the residual stresses in cylinder specimen of quenched S45C and SCr420 steel are measured by the neutron diffraction method. In addition, the measured results of XRD, neutron diffraction as well as calculated value are compared and discussed. As the result, the non-distortion lattice spacing depend on martensite phase are verified. It is feasible to evaluate the residual stress inside of the quenching material combing with measured results and simulation values.
  • 1. 自動車部材の強度と信頼性保証
    河本 洋
    2004 年 53 巻 9 号 p. 1036-1042
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 並木 哲, 陣内 浩, 早川 光敬
    2004 年 53 巻 9 号 p. 1048
    発行日: 2004/09/15
    公開日: 2009/06/03
    ジャーナル フリー
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