日本機械学会論文集 A編
Online ISSN : 1884-8338
Print ISSN : 0387-5008
73 巻, 727 号
選択された号の論文の18件中1~18を表示しています
  • 橋村 徹, M. Fauzan ADZIMAN, 岸本 喜久雄
    2007 年 73 巻 727 号 p. 315-322
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    Foamed aluminum has unique impact energy absorption characteristic. In rate years, use to safety members of machinery for transportation such as a car, a train or a aircraft, foamed aluminum has been examined to make use of the lightweight and unique compression plastic deformation characteristics. To use foamed aluminum as safety member, it is necessary to make the member length large to get enough energy absorption. When foamed aluminum is used in the state of the long column instead of a short pillar, it seems that the problem of the outbreak of plastic instability and the compression buckling at the deformation progress could not be avoided. In this paper, basic plastic deformation characteristics of foamed aluminum in short and long column members are investigated. As a result of the examinations, an analytical model of foamed aluminum has proposed to understand and forecast the influence of material uniformity, aspect ratio, piled-up effects. Based on those results, actual sized examination bodies have produced and tested, and reliability of the model was confirmed.
  • 陳 玳〓, 清水 祐輝
    2007 年 73 巻 727 号 p. 323-330
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    In this paper, circumferential strain concentration in cylindrical and square tubes with corrugated surface subjected to axial compression are studied by using finite element method. For cylindrical tubes, the yielding tress σy, hardening coefficient Eh of material and thickness t of tube have only a small influence on the strain concentration, and maximum circumferential strain can be evaluated approximately as a function of wavelength 2λ and amplitude a of corrugation and cylinder radius R. For square tubes, however, effect of the corner radius r, the thickness t, and the yielding stress σy, hardening coefficient Eh on the strain concentration is comparable as wavelength 2λand amplitude a of corrugation. The maximum circumferential strain is larger as the corner radius r/Dis small, as the thickness t is thin, and as ratio of σy/Eh is large.
  • 中澤 嘉明, 田村 憲司, 日下 貴之, 北條 正樹
    2007 年 73 巻 727 号 p. 331-337
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    The effects of cross sectional shape on plastic buckling behavior of thin-walled polygonal shell members were studied to establish a novel design scheme of the energy absorbing members for automobiles. Finite element results showed that the width of planar region of the polygonal shells controlled the buckling interval, where the interval became smaller as the width of planar region decreased. On the other hand, the arc length of ridgeline controlled the buckling load, where the load became larger as the arc length of ridgeline increased. In addition, the arc length of ridgeline affected the stability of buckling behavior. The validity of the above outcomes was demonstrated through a practical design example of automobile parts.
  • 大野 卓志, 小川 武史
    2007 年 73 巻 727 号 p. 338-344
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    Plastic deformation and hardening mechanism of nuclear grade austenitic stainless steel, SUS316NG, at room and cryogenic temperatures were investigated using advanced indentation method and observations by transmission electron microscope (TEM). First, tensile and compressive pre-strains were applied at room temperature up to true strain values of 20%. Detailed indentation testing revealed that the strain hardening was detected when the indentation sizes were more than 50 μm, while it disappeared when the indentation size decreased down to 1 μm. This behavior was explained by the slip band size due to dislocation structure. Dual indenter method successfully predicted the stress-strain response of the pre-strained specimens. Second, Charpy impact tests were performed at room temperature and 77 K. The fracture toughness was sufficiently large at 77 K, however, ductility was slightly decreased compared with that at room temperature. Martensitic transformation was observed near the notch tip for the specimen tested at 77 K. This hardening was detectable by the indentation testing even if the indentation size was less than 1 μm.
  • 小林 道明, 橋場 翔, 青山 尚弘, 三浦 節男, 柴野 純一
    2007 年 73 巻 727 号 p. 345-351
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    In the authors' previous studies, the dependence of ultrasonic wave velocity on the microstructural properties of solid materials under plastic deformation was investigated both theoretically and experimentally. From the results obtained, it has been found that the changes of longitudinal wave velocity under simple and pure shear states are quite different, on the other hand transverse wave velocity changes under both shear states are almost same. These results suggest clearly that the propagating character of ultrasonic waves is dependent upon the interaction between the propagating mode of ultrasonic waves and micro-structural material changes induced by damages due to plastic deformation. In this paper, therefore, to identify the dependence of longitudinal wave velocity on the point defect, the longitudinal wave velocity propagating in a pure Aluminum single crystal under the pure shear plastic deformation is examined for several combinations of crystal orientations and shear slip directions which are determined by the difference of the amount of point defect calculated by the finite element polycrystal model (FEPM).
  • 黒沢 亮, 前崎 渉, 沢 俊行
    2007 年 73 巻 727 号 p. 352-359
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    The contact gasket stress distribution of a non-circular box-shape flange connection with a compressed sheet gasket subjected to internal pressure was analyzed taking account a hysteresis of the gasket using finite element method (FEM). Leakage tests were also conducted using an actual non-circular box-shape flange connection with a compressed sheet gasket under internal pressure. By using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. The difference in the new gasket constants was substantial between the values obtained from the present study and those from the PVRC procedure. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated. It was found that a higher bolt preload was needed for a given tightness parameter in the more safety design of box-shape flange connections.
  • 第3報, マグネシウム合金粒子群の輸送・融解シミュレーション
    尾崎 公一, 藤井 俊樹, 福田 忠生, 辻 和也, 武谷 健吾, 早川 悌二
    2007 年 73 巻 727 号 p. 360-367
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    A numerical simulation method for predicting transport and melting phenomena of Mg alloy particles in an injection molding machine was developed in the present study. Mg alloy particles in the screw groove were treated as a porous material in order to simplify governing equations. The apparent physical properties of the porous material were evaluated with the empirical formulations derived in our previous works. Some other model constants were determined by comparing the numerical and experimental results. As a result, the followings were obtained. The bulk density of the porous material was increased rapidly at a certain position in an injection molding machine. The increasing rate of the bulk density became remarkable in a case of shallower screw groove. The relative angular velocity of Mg alloy against the screw at the inlet was not affected by the angular velocity of the screw at a fixed groove depth, however it was increased with an increasing in the depth of the screw groove at a fixed angular velocity of the screw. At a constant mass flow rate of Mg alloy, the outlet temperature of Mg alloy was increased with an increase in the depth of the screw groove. However, the torque required for screw rotation was not affected by the depth of the screw groove.
  • 岡本 伸吾, 滝 政信, 萩原 多津美, 府山 伸行
    2007 年 73 巻 727 号 p. 368-371
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    The purpose of this study is to ascertain the material properties of metal matrix composite (MMC) that is used to reinforce pistons of automobile engines. The MMC investigated in the present study consisted of metal fibers (Fe75Cr20Si5) in an aluminum alloy matrix (AC8A). Tensile tests were performed on 100%-AC8A and MMC at temperatures of 25°C, 150°C, 250°C and 300°C. The stresses and strains of the test samples were measured ; their yield stresses, Young's moduli and tensile strengths were also determined from the experimental results.
  • 谷江 尚史, 寺崎 健
    2007 年 73 巻 727 号 p. 372-378
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    In previous report, we proposed a new crack propagation model that could automatically calculate crack paths of micro-solder joints in semiconductor structures. In this report, we describe a fracture life evaluation method of micro-solder joints using our crack propagation model. When fatigue life is calculated using a finite element method (FEM), one of the most difficult issues is correcting for the effect of element size. We thus investigated the dependency of the calculated life on the element size and developed a formula for approximating this dependency. Using this formula, we could quantitatively estimate fatigue life regardless of element size. Calculation of the fatigue lives of ball grid array structures in which the diameters of the solder ball differed showed that the estimated life corresponded to the observed life.
  • 野田 尚昭, 徐 春暉, 高瀬 康
    2007 年 73 巻 727 号 p. 379-386
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    In this paper, stress intensity factor for a three dimensional planar interfacial crack is considered on the idea of the body force method. The formulation leads to a system of singular integral equation, whose unknowns are three types of crack opening displacements. The unknown body force densities are approximated by the products of the fundamental density functions and power series; here, the fundamental density functions are chosen to express singular stress fields due to a two-dimensional interface crack exactly. The calculation shows that the present method gives rapidly converging numerical solutions. It is found that the stress intensity factors Ki and Kii are determined by bimaterials constant ε alone, independent of elastic modulus ratio and Poisson's ratio.
  • 上田 整, 近藤 宏憲
    2007 年 73 巻 727 号 p. 387-394
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    A crack in a plate of a functionally graded piezoelectric material mathematically modeled by a nonhomogeneous solid is studied under transient thermal loading conditions. It-is assumed that initially the medium is at the uniform temperature and is suddenly subjected to a uniform temperature rise along the one of the traction-free boundaries. The crack faces are supposed to be completely insulated. Some material properties are assumed to be exponentially dependent on the distance from the crack line parallel to the boundaries of the plate. By using both the Laplace transform and Fourier transform, the thermal and electromechanical problems are reduced to a singular integral equation and a system of singular integral equations. The singular integral equations are solved numerically, and a numerical method is then employed to obtain the time dependent solutions by way of a Laplace inversion technique. The intensity factors vs. time for various material constants and geometric parameters are calculated.
  • 堀辺 忠志, 土田 栄一郎, 荒居 善雄
    2007 年 73 巻 727 号 p. 395-402
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    This paper contains an analysis of the stress and displacement distribution arising in a semi-infinite plate with a circular inclusion when the strip is subjected to tension at infinity. Two types of inclusion, i.e., perfect bonding and sliding inclusion are treated in this paper. The solution which is based on the Papcovich-Neuber displacement potentials is obtained by combining the harmonic potentials in integral forms and infinite series. The boundary conditions of the problem are fully satisfied using the relationships between the harmonic functions of Cartesian and polar coordinates. The effect of the inclusion on the stress and displacement are given in the form of graphs to show the availability of the present method.
  • 古口 日出男, 箱崎 悟史
    2007 年 73 巻 727 号 p. 403-410
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    In the present paper, surface Green function on a half-surface in cubic crystals are derived on the basis of the theory of elasticity. Surface stresses distribute uniformly on a flat and clean surface, although they will vary on the surface with a step due to the existence of step. Boundary condition taking into account surface stresses and surface rigidity is applied to the free surface. Normal stress, which is proportional to the curvature of surface, is added to the boundary condition in the normal direction to the surface. Surface rigidity is incorporated into the boundary condition in the tangential direction. Furthermore, a surface Green function for the surface [001] with a step is derived explicitly under the boundary condition and is used for calculating the displacements near the surface. Surface Green function is applied for determining the strength for surface tractions and dipole forces through a comparison of the theory and MD. Displacements in the theory of elasticity considering surface stresses and surface rigidity are well agreed with those in MD.
  • 速度依存性下負荷面摩擦モデル
    橋口 公一, 尾崎 伸吾
    2007 年 73 巻 727 号 p. 411-418
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    A high friction coefficient is first observed as a sliding between bodies commences, which is called the static-friction. Then, the friction coefficient decreases approaching the lowest stationary value, which is called the kinetic-friction. Thereafter, if the sliding stops for a while and then it starts again, the friction coefficient recovers and a similar behavior as that in the first sliding is reproduced. These facts are fundamental characteristics in the friction phenomenon, which have been widely recognized for a long time. In this article the subloading-surface friction model with a smooth elastic-plastic sliding transition is extended so as to describe these facts by formulating the rate-dependent hardening/softening rule of sliding-yield surface adequately.
  • 乗り上がり脱線回避車輪の創製
    鈴木 秀人, 中村 雅史, 曙 紘之, 金 鷹, 石田 誠
    2007 年 73 巻 727 号 p. 419-425
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    The derailments accident of railroad suffer a large number of casualties, and it occurred sometimes all over the world even now. Many causes of the derailment accident are that the wheel runs on a rail by high friction coefficient contact between the wheel flange and the rail. So, normally the lubricating oil is used in order to prevent the high coefficient contact. However, it has many problems to use the oil, for example oil maintenance cost and care for environmental problems. In this study, in order to achieve the low friction coefficient without using the lubricating oil, the surface modification treatment which indicates excellent tribological properties was suggested, especially DLC (Diamond Like Carbon) coating. Model wheels coated surface modifications were prepared. The friction and abrasion tests assumed actual condition were carried out. It is clear that to coat DLC only has no effect, so it is important to combine two or more surface modifications. By combining the surface modifications, it can be achieved low friction coefficient contact between the wheel flange and the rail without using the lubricating oil enough to prevent the derailments. Further more, in order to achieve more safety wheel, hybrid-MoS2 coating was performed. This wheel indicated significantly low friction coefficient. It is possible to achieve security and safety wheel which can prevent the derailments by using hybrid-DLC and hybrid-MoS2 coating.
  • 五味 健二
    2007 年 73 巻 727 号 p. 426-433
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    This paper introduces the principles and execution of a new technique based on simple polarimetry for minute birefringence measurements. The technique requires only three stepped photoelastic images although conventional phase-stepping methods require four images. To verify the new technique experimentally, two precise crystal wave plates of having 79.1 ± 3.5 and 10.0 ± 4.7 nanometers in retardation were used as specimens. The measurements of the retardation with standard deviation were found to be 77.5 ± 2.61and 10.3 ± 1.11 nanometers respectively, which agreed well and narrowed the deviation in spite of low-level amount of retardation. To estimate the measurement accuracy of the angular orientation of the birefringence, the angular positions of the rotation stage for the specimens were rotated intermittently 10 degrees at a time during the experiments. As a result, the measured offsets of the angular orientations were found to be 10.0 ± 0.906 and 10.0 ± 3.05degrees with standard deviation respectively. It is concluded that the new technique is effective for minute birefringence measurements.
  • 山崎 友裕, 白山 泰久, 平尾 雅彦
    2007 年 73 巻 727 号 p. 434-439
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    Magnetostriction curves of nickel are measured under various levels of applied stress. Several techniques using magnetic properties have been developed for the nondestructive stress measurement in ferromagnetic materials. We have already revealed that the maximum value and the knee point value of the magnetostriction curves can be used for the nondestructive stress evaluation in steel and Invar alloy, respectively. The minimum value of the magnetostriction normal to the magnetization direction was also proved to be useful. Accurate measurement of magnetic field was not required in measuring such characteristic values. In this study, in order to examine the possibility of stress measurement using magnetostriction, we measure the stress dependence of the magnetostriction of nickel in both directions parallel and normal to the magnetic field. The results can be explained considering the domain realignment by the stress. It is found that the saturation values in these magnetostriction curves can be applied to the nondestructive stress evaluation.
  • 佐藤 岳大, 小林 志好, 大塚 年久, 田村 宏
    2007 年 73 巻 727 号 p. 440-446
    発行日: 2007/03/25
    公開日: 2011/03/02
    ジャーナル フリー
    The purpose of this study is to discuss compressive properties of double layer aluminum honeycomb core sandwich panels. At present, the single layer panel is used as the shock absorbing constructed material. If the double layer laminated panel is used instead of the single layer panel, the improvement of the shock absorption will be expected. For a design of the shock absorption, it is very important to make clear both the buckling strength and the buckling energy under the compressive load. Therefore, a series of compression tests were carried out using the laminated panel that changed the core height. As a result, the buckling strength of the laminated panel depended on the highest one in single layer panels that were an equivalent core height to each layer of the laminated panel respectively. Moreover, the buckling energy of the laminated panel was superior to that of single layer panel, when heights of both panels were equivalent.
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