日本機械学会論文集 A編
Online ISSN : 1884-8338
Print ISSN : 0387-5008
66 巻, 650 号
選択された号の論文の21件中1~21を表示しています
  • 大石 篤哉, 吉村 忍, 矢川 元基
    2000 年 66 巻 650 号 p. 1819-1826
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    Computer simulations are about to replace experiments in various fields related to dynamic problems, such as crashworthiness of vehicles, vibration of a nuclear reactor in earthquake and ultrasonic wave propagation in solid with cracks for nondestructive evaluation. For solving such large scale problems, the parallel processing has become a key technology. In this paper, a parallel contact algorithm suitable for a domain decomposition technique is proposed, and implemented on a dynamic finite element analysis code based on an explicit time integration scheme. Parallel efficiency of the code is tested through sample analyses on a PC cluster.
  • 于 強, 野崎 敦敬, 柏村 孝義, 白鳥 正樹
    2000 年 66 巻 650 号 p. 1827-1833
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    The authors have proposed Statistical Design Support System(SDSS)which can be used even on nonlinear behavior. It is an integrated system based on the Response Surface Methodology and the Design of Experiments. The optimization can be performed with this system using small number of case studies. In this paper, they treated with an uncertain variable(an error variable)which the engineering designers cannot control and certain variables(design variables)which the engineering designers can control. In this study, a new robust and optimum design approach was proposed by using SDSS.Using this method, a structure can be optimized for the objective functions without losing the robustness toward the uncertain variable. The application results verify the usability of the approach and SDSS.
  • 福岡 俊道, 高木 知弘
    2000 年 66 巻 650 号 p. 1834-1840
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    In multi-bolt system, the scatter in bolt tension is largely dependent on the method of tightening operation and elastic interaction due to the successive tightening of bolts. In this study, focuses are placed on effects of elastic interaction and a new bolt-up strategy using three-dimensional finite element analysis, in which a gasket is modeled as a nonlinear one-dimensional gasket element, is proposed. Two types of numerical procedures are presented here. One is to predict the final scatter in bolt tension when tightening all bolts one by one in arbitray order with target preload. The other is to predict the amounts of initial bolt loads needed to create uniform final preloads with one pass operation of bolt tightening. The effectiveness of the numerical approach proposed here is substantiated by comparing numerical results with experimental ones. Contact pressure distributions on the gasket bearing surface, which significantly affect the sealing performance of flange connections, are also evaluated. The objective connection is composed of bolts, pipe flanges and a spiral wound gasket with inner and outer rings.
  • 伊藤 洋茂, 齊藤 和宏, 久保 貴博, 高橋 雅士, 柏谷 英夫
    2000 年 66 巻 650 号 p. 1841-1846
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    For studying environmental deterioration and damage, the foreign object impact tests were carried out for thermal barrier coating material by use of gas-gun-type accelerator, and then FEM analysis was conducted for simulating impact damage. As a result, following conclusions were obtained. 1)Impact damage of the single-particle impact test was caused in the boundary between top coating and bond coating, and formed cracks of the delamination which brought the spalling of top coating. 2)From FEM analysis, shear strain arises in the impact point, and extends along the surface of coating. Maximum peak distribution of shear strain almost corresponds to delaminated length. 3)Delaminated length of coating which is equivalent to impact shear strain could be evaluated by standardized kinetic energy of projectile, that is kinetic energy divided by cross sectional area of projectile.
  • 小西 寛, 村上 敬宜, 小林 幹和, 松井 利治
    2000 年 66 巻 650 号 p. 1847-1854
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    In order to clarify the mechanism by which compressive residual stresses are created during shot peening, a 76.2 mm diameter steel ball was repeatedly dropped against selected spots on a flat steel plate. In addition, static indentation of the plate by the same steel ball was also carried out. After the first drop and static indentation, a tensile residual stress was found near the center of the ball indentation mark and the peak of compressive residual stresses was found outside of the indentation. With increasing in the number of drops, the tensile residual stress became compressive. Furthermore, a steel ball attached to a cylindrical weight was dynamically dropped on the center of a fatigue test specimen and a rotating-bending fatigue test was carried out to investigate the effect of residual stresses on the fatigue strength. The fatigue strength of the specimens containing the indentation produced by a dynamic shot decreased remarkably compared to those of unpeened specimens.
  • 〓 建輝, 川越 誠, 水野 渡, 森田 幹郎
    2000 年 66 巻 650 号 p. 1855-1863
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    The effect of injection speed on the fatigue fracture property of polypropylene has been mainly investigated from a low temperature of -40°C to a high temperature of 50°C. Results show that, (1)The thickness of the skin layer(with low hardness)and the intermediate layer(with high hardness)decreases but the thickness of core layer(with middle hardness)increases as the injection-molded speed increases. The ductile property of all specimens becomes better. (2)In the all fatigue fracture test, the origin of crack from intermediate layer of high hardness and propagation of the crack leads the specimen to rapture. (3)Under the condition that the temperature(20°C, 50°C)is over the room temperature, fatigue tests show that the life of specimen becomes longer as the injection-molded speed increases. (4)Under a lower temperature(-40°C, -10°C), fatigue tests show that the value of tanσ decrease but the E does not in the fatigue process of all specimens. There is a tendency of brittle fracture. The fatigue life of specimes made with the injection-molded speed of 22cm3/s is the shortest for the thickness and hardness distributions in each layer of specimen sections are strongly interrelated. (5)Under all the test temperature, the status of fatigue crack took placed in a layer in closely related to the injection-molded speed. It has great influence on the specimen fracture mechanism.
  • 八戸 敦司, 河井 昌道
    2000 年 66 巻 650 号 p. 1864-1871
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    Two-stress level fatigue strengths of unidirectional GLARE 2 laminates have been studied using various off-axis plain coupon specimens. Tension-tension fatigue tests accompanied by a single change in the stress amplitude were performed for step-up and step-down sequences. History-dependence of the growth of fatigue damage under two-stress amplitude conditions was elucidated through comparisons with the results of constant-amplitude fatigue tests. The residual lifetimes under two-level fatigue loading were significantly dependent on the sequence of fatigue loads and on the off-axis angles of specimens, so that they deviated markedly from those under constantamplitude fatigue loading. To highlight the significance of the non-linear accumulation of fatigue damage under two-stress level conditions the residual lifetimes of the specimens damaged by prior fatigue were compared with the predictions using the Palmgren-Miner's linear accumulation theory. Applicability of existing theories for a non-linear accumulation of fatigue damage was also evaluated on the basis of the experimental results.
  • 瀬戸口 克哉, 高瀬 徹, 中村 匡宏, 村上 寛和
    2000 年 66 巻 650 号 p. 1872-1877
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    In order to investigate applicability of the life prediction method for smooth specimens subjected to two-step loadings, axial load controlled fatigue tests under two-step loading were carried out using rolled bolt-nut joints. It was concluded that this life prediction method for smooth specimens was applicable to life prediction of rolled bolt-nut joints and the minimum accumulated life-fraction at failure, Df, was 0.74 when the life-franction due to primary stress was about 0.5. Then, dividing the cycles corresponding to this condition of the minimum Df into 2, 4 and 8 blocks, fatigue tests under two-level multi-step loading were carried out by repeating the divided cycles alternately. As a result, Df became equal to about 1. Life prediction were tried and a modified linear damage rule taking into account the loading history and material properties was proposed. Fairly good agreement was obtained between predicted and experimental results. According to this prediction method, it was known there were cases of smaller Df under two-level multi-step loading than the minimum Df under two-step loading.
  • 松井 勝幸, 衛藤 洋仁, 雪竹 克也, 三阪 佳孝, 安藤 柱
    2000 年 66 巻 650 号 p. 1878-1885
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    The surface refining method is a useful technique to improve the fatigue limit of gears. One of the methods is the Carburizing Method. To increase the fatigue limit of the Carburized gears, the following five techniques need to be developed:a)Reduce abnormal surface structure. b)Obtain a fine grain size. c) Decrease the retained Austenitic structure. d)Increase hardness under the surface. e)Improve the residual stress distribution under the surface. For this purpose, the authors conducted a study by using DSG1 steel gears on the new compound surface refining method consisting of Vacuum Carburizing, Contour Induction Hardening and Double Shot Peening. The results showed that the fatigue limit of the gears processed by the new compound surface refining method achieved 125% better than that of the conventional Vacuum Carburized gears.
  • 小野 裕之, 荒木 栄敏, 齊藤 憲司
    2000 年 66 巻 650 号 p. 1886-1893
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    Micromechanical modeling of an intelligent material containing TiNi fibers is performed by taking into consideration of the existence of crack bridging fibers with transformation strain which corresponds to the total amount of shrinkage of the fiber. In modeling, thermal expansion strain due to the mismatch of thermal expansion coefficients between TiNi fiber and matrix is also considered. The stress and strain fields in the matrix, fibers, and fictious eigenstrain in cracks can be found, hence the total potential energy of the model will be derived from these fields. By using the total potential energy, the stress intensity factor at the tip of crack in the material will be expressed successfully in terms of the transformation strain of fibers and the thermal expansion strain occurred in the material.
  • 小野 裕之, 荒木 栄敏, 齊藤 憲司
    2000 年 66 巻 650 号 p. 1894-1900
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    In the previous study, micromechanical modeling of the intelligent material containing TiNi fibers was performed and the stress intensity factor K1 could be expressed in terms of the magnitude of shape memory shrinkage of fibers and the thermal expansion strain occurred in the material. In this study, by using the analytical results, the value of K1 will be numerically calculated. As a result, we can see that the K1 value decreases with increasing in the shrink strain of fibers. This tendency agree with that of the experimental result obtained by Shimamoto et al. Moreover, it can be seen that there exists the optimal value of shrink strain of fibers to make the K1 value zero. The change in K1 with temperature during heating process to the inverse austenitic temperature of TiNi fiber is also consistent with the experimental result. The results obtained can be explained by the shrink strain, the thermal expansion strain, and the elastic moduli of TiNi fiber. These results may be useful in designing the intelligent material containing TiNi fibers from the viewpoint of crack closure.
  • 村澤 剛, 東郷 敬一郎, 石井 仁
    2000 年 66 巻 650 号 p. 1901-1907
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    Composites containing NiTi shape memory alloy fibers or Ti fiber in a Polycarbonate matrix have been fabricated by the injection modling technique. In the shap memory ally(SMA) composites, two kinds of NiTi fibers showing the shape memory effect(SME)and the psuedoelasticity(PE) at room temperature are used. Fracture behavior under uniaxial tension and deformation behavior under thermo-mechanical loading are examined on the composites. The obtained results are as follows:(1)The stress-strain relation up to the final fracture of the SMA composites showed the repeated up-and-down of the stress which corresponds to the necking of the specimen, fiber fracture and matrix fracture. (2)The strain for the initiation of necking and the strain for the fiber or matrix fracture in the SMA composites were higher than those in the Ti composite. This is attributed to the unique stress-strain relations accompanied by the stress-induced martensitic transformation of the SMA fibers. (3)The SMA composite containing PE fiber exhibited the psuedoelastic deformation under tensile loading-unloading. (4)The SMA composite containing SME fiber exhibited the contraction by heating after tensile loading-unloading, but the compressive residual stress in the matrix expected in this process was not remarkable.
  • 小木曽 望, 嘉藤 伸一, 室津 義定
    2000 年 66 巻 650 号 p. 1908-1915
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    This study is concerned with the reliability analysis of a cantilever of a laminated thin composite pipe subjected to tensile, bending and torsional loadings. The reliability is evaluated by modeling the pipe as a series system consisting of each ply failure based on Tsai-Wu criterion. Additionally, the pipe is considered as in failure when the tip displacement is larger than an allowable limit. The mode reliability is obtained by the first order reliability method, where material properties and applied loads are treated as random variables. The system rebiability is approximated by Ditlevsen's bound. Through numerical calculation, the change of the reliability in terms of ply orientation angle is illustrated. Then, the variation of the shear strength is shown to have a large effect on the reliability. Finally, it is shown that a reliability-based optimum ply orientation angle with the elastic failure mode is much different from the optimum angle without the elastic failure mode.
  • 青山 博, 渡邊 洋之, 武田 展雄
    2000 年 66 巻 650 号 p. 1916-1921
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    Alimina-fiber-reinforced epoxy(alumina/epoxy)is eften used to fabricate to the thermal insulating structire of a superconducting magnet because it has low thermal conductivity and high bending stiffness and strength. The stiffsess of the alumina/epoxy structure is one of the governing factors when evaluating the soundness of a supercenducting magnet. So, to evaluate the soundness of this system, the relation between the degradation in stiffness and the growth in the size of defects in alumina/epoxy must be determined. For this purpose, a new defect-monitoring method using transmitted light through alumina/epoxy was developed. Any defect inside a semi-transparent alumina/epoxy laminate will scatter the light and decrease its intensity. The spectra of the transmitted light were measured using a spectrometer and a halogen lamp. The amplitude of the transmitted light decreased as the stiffness decreased, and the amplitude decreasing ratio was approximately constant from 400nm to 800 nm.
  • 王 清, 野田 尚昭, 本田 昌章, 陳 夢成
    2000 年 66 巻 650 号 p. 1922-1927
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    In this paper a singular integral equation method is applied to calculate the distribution of stress intensity factor along the crack front of a 3D rectangular crack. The stress field induced by body force doublet in an infinite body is used as the fundamental solution. Then, the problem is formulated as integral equation with a singularity of the form r-3. In solving the integral equation, the unknown functions of body force densities are approxi-mated by the product of a polynomial and a fundamental density function, which expresses stress singularity along the crack front in an infinite body. The calculation shows that the present method gives the smooth variation of stress intensity factors along the crack front for various aspect ratio. The present method gives rapidly converging numerical results and highly satisfied boundary conditions throughout the crack boundary.
  • 平島 健一, 小楠 幹宏, 広瀬 幸雄
    2000 年 66 巻 650 号 p. 1928-1935
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    This paper presents the solutions of multilayered concentric circular rings around the most inner solid inclusion with imperfect interfaces in an infinite plane under in-plane and out-of-plane shear stresses at infinity. Imperfect interfaces are modeled as spring layer models with various thickness. These solutions are provided in terms of Airy's stress functions and obtained for the cased with any numbers of layerd interfaces to solve simaltaneous linear equations. Using these solutions, Using these solutions, several numerical examles are shown by graphical representation. As the conclusion, stresses in the most inner solid inclusion with multilayered civcular rings are not constant valaes under the in-plane load and are constant values under the out-of-plane shear load.
  • 江上 登, 加賀谷 忠治, 井上 宣之, 竹下 弘秋, 水谷 肇
    2000 年 66 巻 650 号 p. 1936-1942
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    This study examines the effect of hybrid surface modification by vacuum carburizing and fine particle peening on fatigue strength behaviors of SCM 415 material. We used quenched vacuum carburized and hybrid, vacuum carburized and fine particle peened, specimen made of SCM 415 and measured their hardness distribution, mechanical properties, fatigue strength and crack propagation. In terms of the fatigue behaviors, we investigated the relationship between the crack propagation rate da/dN and stress intensity factor range △K, da/dN and effective stress intensity factor range △Keff, as well as the fatigue crack initiation life Ni and crack failure life Nf of specimens. The results show specimens with hybird surface modification are effective in the prevention of fatigue crack initiation and fatigue crack propagation.
  • 徳田 正孝, P Sittner, 高倉 正佳, 土師 学
    2000 年 66 巻 650 号 p. 1943-1948
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    The inelastic behavior of shape memory alloy under multi-axial loading conditions were investigated by applying the combined loads of axial force and torque to the thin-walled tube specimen made of Cu-based shape memory alloy. In this paper, some quite unique behavior obtained by the experiments are shown and discussed, which can not be observed in the uniaxial experiments, including the path dependency created by the change of microstructure(especially several number of variants operate simultaneously). The results obtained here manifest the significance of the constitutive equation formulated on the basis of the semi-microscopic approach in the 1st report.
  • 太田 裕之, 飯島 晋平
    2000 年 66 巻 650 号 p. 1949-1954
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    With the increasing level of integration in semiconductor devices, Ta2O5 thin film is attracting much interest for use in the capacitors of semiconductor memory devices because of its high dielectric constant. In the fabrication process of the device, the Ta2O5 thin film is deposited in the amorphous condition and then crystallized by annealing. In order to increase the mechanical reliability of the capacitors, the change in mechnical properties of the Ta2O5 film during crystallization must be determined. The Young's modulus was therefore measured by the three-point bending method, and residual stress and thermal expansion coefficient were calculated by measuring the curvature of a substrate with the Ta2O5 film. It was found that the crystallization increases the residual stress of the film from 250 to 400 MPa and the Young's modulus from 130 to 180 GPa.And the thermal expansion coefficient is decreased from 5.7×10-6 to 3.6×10-6.
  • 伊澤 義明, 田中 亮, 伊藤 耿一
    2000 年 66 巻 650 号 p. 1955-1960
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    The anisotropies of sheet metals are caused from the texture developed by a cold rolling process. The crystal grains in the texture take a partial direction, and the strength of the texture is different from that of the surrounding material. When the sheet metals are deformed with changes of the strain path, the difference of the strength brings a new texture and causes a new anisotropic principal axis. Therefore, it is supposed easily that the principal axis of anisotropies dose not behave like the material fiber printed on the sheet metals. To confirm the assumption, in this paper, a measuring method of revolution angles of principal axes is proposed by using a laser speckle strain meter. The revolution angle is measured by investigating the distribution of r-values with respect to the tension directions. Finally, a dynamical model of the principal axes is derived and its parameters are identified.
  • 西尾 一政, 益本 広久
    2000 年 66 巻 650 号 p. 1961-1968
    発行日: 2000/10/25
    公開日: 2008/02/21
    ジャーナル フリー
    The fusion weldings of the spheroidal graphite cast irons are very difficult because cracks are initiated in the weld metal and the heat affected zone. However, since the diffusion bondings are performed on the solid state of the materials, the sound bondings would be obtained between the cast irons and also between the cast iron and the mild steel with Ni foil as an insert metal. When the bonding surface has a conical configuration, Ni plating to the surface might be useful instead of the Ni foil as an insert metal. In this study, the diffusion bondings were applied to the bondings between the cast iron and the machine-structural carbon steel. It was made clear that the bondability of the materials with Ni plating method was superior to that with Ni foil.
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