日本機械学会論文集 A編
Online ISSN : 1884-8338
Print ISSN : 0387-5008
66 巻, 647 号
選択された号の論文の28件中1~28を表示しています
  • 山地 成一, 松田 博和
    2000 年 66 巻 647 号 p. 1247-1252
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The boundary element method (BEM) has been producing positive results in fields where analysis is possible only by boundary integration, such as elastostatics problems. However, in natural vibration analysis using the fundamental solutions of elastostatics, or internal heat generation or initial temperature distribution in unsteady heat conduction analysis, domain integration is required. Authors have developed an efficient equivalent mass method for nutural vibration analysis problems and has been applying it to actual equipments. In this paper authors try to apply the equivalent mass method to problems involving domain integrals of unsteady heat conduction analysis.
  • 渡部 修, 渡辺 千城
    2000 年 66 巻 647 号 p. 1253-1261
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A parallel finite element analysis based on a domain decomposition method (DDM) is considered for the analysis of thermal and mechanical coupling behavior. In the present DDM, an analysis domain is divided into a number of smaller subdomains without cverlap. The mechanical responce analysis for the subdomain is performed under the constraint of displacement and traction force as is developed by Yagawa et al., while heat transfer analysis is carried out under the constraint of temperature and heat flux in the present paper. The constraint is satisfied through iterative calculation algorithm based on the conjugate gradient method. The characteristics of domain decomposition method implemented on a parallel computer consisted of PC cluster is studied by the transient thermal stress analysis in a nozzle of FBR.
  • 畔上 秀幸, 須貝 康弘, 下田 昌利
    2000 年 66 巻 647 号 p. 1262-1267
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A shape optimization method for linear buckling load maximization problems of continua is presented. Using a one-parameter family of mappings defined in a domain where a continuum lies initially, a buckling load maximization problem considering multimodal conditions was formulated. The shape gradient density function for the problem was derived using the Lagrange multiplier method and the formula of the material derivative. The shape gradient density function was then used in a shape optimization analysis conducted with the traction method. The validity of the proposed method was demonstrated by numerical analyses of column-like and arch-like two-dimensional continua in a plane strain condition.
  • 高橋 徹, 西村 直志, 小林 昭一
    2000 年 66 巻 647 号 p. 1268-1273
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In this paper, a panel clustering boundary integral equation method for the diffusion equation in 2D in time domain is developed. The present method can reduce the computational costs and memory requirement drastically. In numerical examples, it is shown that the proposed method solves the large scale problems faster than the conventional one.
  • 小林 峰雄, 大野 信忠
    2000 年 66 巻 647 号 p. 1274-1280
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    This paper describes fully implicit integration and consistent tangent stiffness of rate-independent cyclic plastic constitutive models in which a general form of strain hardening and dynamic recovery is employed to represent the multilinear, as well as nonlinear, evolution of back stress. First, using the backward Euler discretization and the return mapping algorithm, a nonlinear scalar equation is derived to determine the increment of plastic strain induced by a prescribed strain increment in initially isotropic materials. A successive substitution method is suggested to solve the nonlinear equation and to complete the implicit integration. Then, the discretized constitutive relations are differentiated to derive a consistent tangent modulus, in which the generality of strain hardening and dynamic recovery is retained for the evolution of back stress. Finally, the constitutive parameters introduced in deriving the nonlinear scalar equation and the consistent tangent modulus are specified for three nonlinear kinematic hardening rules, which have different forms of dynamic recovery, leading to their distinctive capabilities of simulating ratchetting and cyclic stress relaxation.
  • 小林 峰雄, 大野 信忠
    2000 年 66 巻 647 号 p. 1281-1289
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    This report deals with verification of the integration algorithm and consistent tangent modulus obtained in the 1st report for strain hardening and dynamic recovery based cyclic plasticity models. First, it is shown that the nonlinear scalar equation in the integration algorithm can be solved iteratively using successive substitution ; i. e., the Lipschitz constant in this successive substitution is determined and proved to satisfy the condition of convergence. Then, the results derived in the 1st report are coded in a user subroutine UMAT of a commercially available FEM software ABAQUS, and thus uniaxial tensile deformation and cyclic loading of a notched bar are analyzed. A linear combination of the Armstrong-Frederick rule and the Ohno-Wang rule is employed for the coding. It is shown that the iteration for solving the nonlinear scalar equation converges well, that the integration algorithm is stable and allows us to take large increments of strain, and that the consistent tangent modulus really sffords the parabolic convergence in solving the nonlinear equilibrium equation in FEM.
  • 志澤 一之, 若林 宏樹
    2000 年 66 巻 647 号 p. 1290-1296
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A thermomechanical theory of elastoplasticity, including kinematic hardening at finite strain, is developed by introducing the concept of dislocation density tensor. The theory is self-consistent and is based on two fundamental principles, the principle of increase of entropy and the maximal entropy production rate. The thermomechanically consistent constitutive equations for plastic deformation rate, plasticspin and dislocation drift rate are rigorously derived. Constitutive equation of the plastic spin is directly obtained by taking account of a work associating with plastic spin and deriving stress. An expression for the back stress is given as a balance equation expressing equilibrium between internal stress and microstress conjugate to the dislocation density tensor. Moreover, it is shown that the present theory is sufficiently consistent with the theory of non-Riemannian plasticity.
  • 清水 一郎, 奥田 貴雄, 阿部 武治, 谷 英明
    2000 年 66 巻 647 号 p. 1297-1303
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Changes in the surface roughening and the inhomogeneous deformation behavior of respective grains of polycrystalline iron during uniaxial tension are experimentally investigated. The shape of the roughened surface is measured three-dimensionally at each step of the tensile deformation. The profiles of respective grains are obtained from a photograph of the scanning electron microscope, and the principal strain of the grain is calculated from the axis of the approximated ellipse of the strain distribution of the grain. Thus, the relation between the change in the roughened surface and the deformation of grain is discussed. It is found that the surface roughness proportionally increases with the applied strain until the necking becomes obvious. The amplitude of the surface roughness grows, and the mountains of the roughened surface elongate in the axial direction during tensile deformation. On the other hand, the respective grains continue to deform during tensile deformation, though the increase ratio of the maximum principal strain is different for individual grains. These results mean that the surface roughening is closely related to the mutual rotation of grains, and the roughness grows due to the difference in the deformation behavior of respective grains.
  • 高原 渉, 俣野 健児, 村田 雅人
    2000 年 66 巻 647 号 p. 1304-1307
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    High temperature deformation behavior under cyclic loading are investigated in air for Si3N4 ceramics at 1673 K. Deformation recovery is observed and it is due to the viscosity of grain boundary phase in ceramics. As the loading cycles increase, the cumulative permanent deformation also increases. However, the total amount of permanent deformation lessens in the case of relatively long holdig time under no stress in the wave pattern. It seems that the cumulative plastic strain is the effective measurement values both to evaluate the damage states and to predict the fracture life time in Si3N4 ceramics at high temperature.
  • 尾田 十八, 高林 徹, 山本 秀樹
    2000 年 66 巻 647 号 p. 1308-1313
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    For the windshield of automobiles, laminated glass with bilayer glass of the same thickness and interlayer polyvinyl butyral is usually used. Recently, asymmetrically laminated glass with thinner inside glass is used in order to reduce the weight without loosing the safety. On the other hand, it is well known that the impact strength of the laminated glass is infulenced by the initial crack occurred after car crashed. In this study, the symmetrically and asymmetrically lamineted glass are impacted through the airbag by the striker shot from a special experimental apparatus. The fracture behavior of the laminated glass without and with three types of the initial crack, are observed and compared. Based on the analysis results of the corresponding discrete element models, the impact fracture mechanism of the lamineted glass is investigated.
  • 堀辺 忠志, 浅野 直輝, 岡村 弘之
    2000 年 66 巻 647 号 p. 1314-1321
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In this paper a crack identification method of plane frame is presented using both genetic algorithm (GA) and FEM. The crack is simulated by an equivalent rotational spring model. On the basis of this approximate model, the stiffness matrices of a cracked element are developed employing the Timoshenko beam thory. In order to calculate the natural frequencies of the frame, which are required to identify of the crack location and depth from frequency measurements, FEM program including the cracked element is written. The depth and the position of the crack in the plane frame are estimated by using these natural frequencies and GA. The proposed method is verified by numerical simulation of some sample problems.
  • 村上 敬宜, 井上 雅弘, 末岡 淳男, 小田原 悟, 小林 正和, 藤原 直樹
    2000 年 66 巻 647 号 p. 1322-1330
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The mechanism of fatigue failure by flow-induced vibration was studied by using a newly developed small wind tunnel. The necessary conditions of flow-induced vibration for a carbon steel specimen attached to a larger styrofoam cylinder were first investigated. Possible methods to detect indications of fatigue crack initiation and propagation were sought. A fatigue life prediction method was also developed. The change in natural frequency and amplitude of the test cylinder and strain history at the prospective crack initiation sites were measured. The 0.45 C steel specimen contained an artificial small hole which is expected to become the crack initiation site. A small portable service strain histogram recorder (Mini Rainflow Corder, MRC) developed in another project was used to monitor the variation of strains due to crack growth from the small hole. Fatigue damage accumulation based on Miner's rule was calculated and compared with the experimental results.
  • 丁 剣, 西田 新一, 服部 信祐
    2000 年 66 巻 647 号 p. 1331-1336
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Axial cyclic tension-compression fatigue test has been performed about the typical austenitic stainless steel (SUS 304) using a servo-controlled electro-hydraulic fatigue tester. The main object of this study is to investigate the effect of strain aging and overstress on fatigue property of SUS 304, which is applied just after fatigue micro-crack initiation. The main results obtained in this study are summarized as follows : (1) The effect of strain aging on fatigue property which has not been observed in high cycle rotating bending fatigue test, is obviously recognized in low cycle axial compression-tension test. (2) The fatigue life (σa=300MPa) is enhanced 211.1 times by the combination of overstress and aging treatment. The reason concerning in this outstanding effect is that, strain aging does play a much more significant role for improving the fatigue strength besides the strain hardening and austenite-martensite transformation caused by overstress. (3) Non-propagating fatigue micro-crack is observed in the specimen, which has been suffered under the stress amplitude of fatigue limit by 1×107 cycles, with combining overstress (525MPa, 50 sec) with aging treatment (350°C×2hrs).
  • 森本 精洋, 松本 [エイ]一, 武田 晴之
    2000 年 66 巻 647 号 p. 1337-1342
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Two kinds of the as-received and the heat treated structural steel, the nickel-chromium alloy and the copper alloy were selected for this investigation. The rolling contact fatigue test, the pulsating compression fatigue test and the completely reversed torsion fatigue test were conducted. The relationships of the fatigue limit among the rolling contact fatigue, the pulsating compression fatigue and the completely reversed torsion fatigue were examined on the basis of the experimental observation. Consequently the fatigue limit P0 under the rolling contact fatigue test could be estimated from the tensile strength σB, the yield stress σy and Young's modulus E as P0=0.07σB√(E/σy. )
  • 高橋 浩之, 向井 稔, 川上 崇
    2000 年 66 巻 647 号 p. 1343-1349
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The fatigue life estimation of micro solder joints is one of the most critical technologies for the reliable IC packages. In recent years, it is considered that the development of estimation methods for the crack propagation based on the fracture mechanics approach is important to the life prediction. In this study, the crack propagation behavior of Sn-37 Pb solder was investigated. Fatigue tests using CT specimens were carried out under 0.1 Hz, 0.01 Hz and 0.001 Hz. As a result, the crack propagation rate was correlated well with the fatigue J-integral range independently of the frequency. On the other hand, the fracture surfaces for all conditions were intergranular creep types. The creep-fatigue tests under stress waveforms with tensile hold (cp-type) and with tensile and compressive hold (cc-type) were carried out at room temperature using CCT specimens. The relationship between the crack propagation rate and the creep J-integral range was obtained. The crack propagation rate under the cc-type condition was lower than the one under the cp-type condition for the same value of creep J-integral range.
  • 山田 春彦, 猿木 勝司, 小川 一義
    2000 年 66 巻 647 号 p. 1350-1354
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The torsional fatigue tests of bulk 63 Sn-37Pb solder were carried out under the condition of test temperature 233-393 K, strain frequency 0.5-0.005Hz and strain hold time 0-99 sec. The followings were shown from the results of the tests in which the test temperature and the strain frequency were varied. The fatigue life was determined only by the inelastic strain range of the stress-strain loop, not influenced by the test temperature and strain frequency. Coffin-Manson law held good in the relationship between the fatigue life and the inelastic strain range. While, in the case of the test in which the strain hold was added, the fatigue life correlated to the inelastic strain range, decreased by the strain hold in the case that the ramp (strain change slope) time was short. In the case that ramp time was long, however, it did not decrease and the Coffin-Manson relation was similar to that of non hold. In this case, the data were able to be put ingood order by assumption that linear damage law held good on the ramp damage and the hold damage respectively.
  • 田中 雄樹, 轟 章, 島村 佳伸, 小林 英男, 中村 春夫
    2000 年 66 巻 647 号 p. 1355-1361
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In the present study, an electric resistance change method is adopted for the identifications of delamination crack location and size of CFRP laminates, and possibility of identification of delamination cracks is experimentally investigated by using cross-ply laminates. 3-point-bending tests to create delamination cracks are conducted using CFRP composite specimens with multiple electrodes, and electric resistance changes due to the delamination are measured. Response surfaces to estimate delamination location and size from electric resistance changes are constructed. In this method, stacking sequence and number of electrodes largely affect reliability of identification of the delamination location and size. In order to estimate these effects, a large number of experiments are conducted by using five kinds of specimens that have different stacking sequences and number of electrodes. As a result, the electric resistance change method can be useful for structures monitoring of laminate of various stacking sequences, and five electrodes are needed for high reliability.
  • 戸谷 眞之, 小田 美紀男, ララック インディヨノ, 有冨 正男
    2000 年 66 巻 647 号 p. 1362-1369
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Energy release rate of an edge delamination of a laminated beam subject to a through-thickness temperature gradient is analyzed on the basis of the classical beam theory. Further, the decomposition of the energy release rate into mode I and mode II components is made by combining the analyses of the energy release rate of an interfacial crack by Toya (1992) and the two-dimensional linear beam solutions by Suo and Hutchinson (1990). The energy release rate is a quadric function of the temperatures at the top and the bottom surfaces of the layered beam and the mode of delamination growth changes from pure mode II to mixed mode type at the temperature difference at which energy release rate takes minimum value. Assuming several values of Bio number characterizing the heat flow across the delamination surfaces, numerical analyses based on the finite element method are carried out. It is shown that the theory agrees well with numerical analyses if the temperature jump across the crack faces is small (when Bio number is larger than 7).
  • 小川 和洋, 庄子 哲雄, 青木 久彦, 藤田 範生, 鳥越 泰治
    2000 年 66 巻 647 号 p. 1370-1376
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A two-layer plasma sprayed thermal barrier coating on Ni base superalloy substrate was characterized. The coating was comprised of an inner layer of MCrAlY bond coating and an outer layer of 8wt% yttria stabilized zirconia (YSZ) thermal barrier coating (TBC). After aging, the reaction layer at interface between YSZ and MCrAlY was observed. The reaction layer had two different contrast layers in the SEM images. One was black which was closer to MCrAlY and the other was gray which was closer to YSZ. The thickness of both layers increased with aging. Also countless porosities at the gray layer and microcrack at YSZ were observed. Most of the macrocrack grew through the porosities. From this viewpoint one may say that the mechanism of macrocrack formation is a deterioration of adhesion which was accompanied by an increase of the porosities or the microcrack.
  • 岩瀬 敏昭, 平島 健一
    2000 年 66 巻 647 号 p. 1377-1384
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In the present paper, the analytical treatments of dynamic behavior of beams under moving loads with spring and damping are shown by using of transfer matrix method to determine the natural frequencies and mode shapes of the beams. We adopt the analytical theories such as Classical, Timoshenko's and Levinson's beam theories for the computations of dynamic behavior of multispan beam, in which the latter two theories take into consideration of the shear deformation and rotatory inertia of the beams. The accuracy, dynamic responses of multispan beams are illustrated through several numerical results by using of the three theories.
  • 初田 俊雄, 坂田 荘司
    2000 年 66 巻 647 号 p. 1385-1391
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A fit structure composed of a square-cross-section shaft and a square-holed lever is often used as a torque-transmitting mechanism. This structure can be degraded, however, if it is subjected to repeated dynamic loads. If the clearance between the shaft and the lever grows too wide, the structure may not be able to transmit the torque smoothly. We studied this growth in the clearance for a fit structure used in electrical machinery. We found that the initial clearance due to the difference in size between the shaft and lever causes plastic deformation to begin in the early stage of loading. This enlarges clearance at the point where the shaft and lever make contact. Also, under dynamic loading, the increase in the clearance increases the service load on the fit structure. We estimated the growth in the clearance by comparing the magnitudes of the resistance of the structure and of the service load for the same clearance.
  • 島津 ひろみ, 三浦 英生
    2000 年 66 巻 647 号 p. 1392-1397
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The silicidation-induced stress developing during Co-silicide formation was discussed experimentally. Co films deposited on Si substrates were annealed to form the silicide films. The formation of CoSi and CoSi2 started at about 400°C and 600°C, respectively. The stress-development mechanism in the reacted films was discussed based on the measurement results of both the internal stress and the thermal stress of Co, CoSi and CoSi2 films. Silicidation-induced stress was defined as the difference between the measured internal stress after the silicidation and the assumed internal stress which was calculated by extending thermal stress curve before silicidation. The silicidation-induced stresses were about 300 MPa for CoSi formation and about 500 MPa for CoSi2 formation.
  • 北岡 征一郎, 宇田 康弘, 矢田 純平
    2000 年 66 巻 647 号 p. 1398-1403
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The condition of grain growth or slip line occurrence at the periphery of microcircular holes in a copper foil is fundamental to biaxial stress measurement by an electrodeposited copper foil with a microcircular hole, and that condition depends on the difference of the Poisson's ratio between the element where stress measured and a copper foil attached to it. In this report, basic equations of biaxial stress measurement, which takes into account of the difference of Poisson's ratio, are presented and the propriety of the equations is examined by plane bending and bending-torsion tests using materials with various Poisson's ratio and Young's modulus.
  • 木村 和成, 藤山 一成, 石井 龍一, 斎藤 潔
    2000 年 66 巻 647 号 p. 1404-1410
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The correlation between creep damage and hardness was obtained for the modified 9 Cr-1 Mo steel specimens crept in laboratory. The hardness became softer as the creep damage increased. The theoretical formulation of softening was done based on the kinetics of the dislocation structure. The formula gave quantitative correlation among the creep conditions of stress, temperature, creep time and Vickers hasdness. The effect of the creep conditions and initial hardness of the material on the creep damage vs. hardness correlation was analyzed, and a practical creep damage curve was proposed which should be used for the creep damage assessment in actual and aged components made of the modified 9 Cr-1 Mo steel.
  • 木村 和成, 藤山 一成, 石井 龍一, 斎藤 潔
    2000 年 66 巻 647 号 p. 1411-1418
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The voids were observed in the fine grained heat affected zone of the creep damaged modified 9Cr-1 Mo steel welded joint. And, the correlation between creep damage and area fraction of void was obtained. The area fraction of void increased as the creep damage increased depending on the creep conditions. The theoretical formula of the correlation among the area fraction of void, creep damage and creep conditions was derived based on the creep deformation kinetics. The distribution of voids was not uniform along the radial axis of the round bar creep specimen. The stress state under creep was analyzed by FEM and the effect on the distribution of voids was investigated. In the fine grained heat sffected zone, the tri-axial stress state was realized under the uni-axial creep test and it was shown that the creep damage by axial stress played an important role on the distribution of voids.
  • 松浦 洋司, 鍛冶 篤
    2000 年 66 巻 647 号 p. 1419-1424
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Partial penetration butt welded joints are widely used, because they require relatively less weld metal to make a joint. However, the unwelded zone acts like a crack. When the size of crack in material is known, the tensile-strength of the material can be estimated using fracture mechanics. This paper deals with a practical method of estimating the size of crack (the unwelded zone in a partial penetration butt welded joint) using ultrasonic testing. The probe refraction angle and a method of ultrasonic testing are discussed. In addition, the tensile-strength of welded joints are also estimated using fracture mechanics, and are found to be in good agreement with experimental results.
  • 浅野 明雄, 関 祥子, 佐藤 良一
    2000 年 66 巻 647 号 p. 1425-1431
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Stresses and stiffnesses of band adhesive box section cantilever beams with a concentrated load at the free end have been studied analytically. The influences of adhered pitches, width and thickness of adhesive layers on the stress distributions and the bending rigidities were investigated. Maximum shear stress in the adhesives occurs at an intersection of the adhered boundary and the inner edge of flange, and it decreases with increase in the width and the thickness of the adhesive layer, also with decrease in the adhered pitch. The analytical results were consistent with the results of finite element methods and experiments.
  • 村上 小百合, 本間 恭二, 跡見 順子
    2000 年 66 巻 647 号 p. 1432-1438
    発行日: 2000/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Experiment of mechanical stimulus was carried out with myoblast cultured on collagen coated silicone sheet subjected to tension for 6 hours to investigate morphological response of the cell. Pictures of its morphological change were taken in computer by CCD camera in every 10 minutes for 8 hours. Both shape index (SI) and cumulative migration for a lot of cells were measured in every 1 hour. SI was increased after tension exposure. In contrast, migration velocity was decreased after tension exposure. Fluid force acts on cytoskeleton during tension exposure as the shape of cell changes. Actin filament as a cytoskeleton and cytosol were modeled to an elastic cylinder and viscous fluid, respectively, to calculate the stress of filament by the fluid-structure interaction analysis. As a result, the maximum stress was 20 Pa, which is consistent with strain velocity provided by the experiment. Taking into account of its Young's Modulus, the rupture of filaments does not cause to increase SI of myoblasts.
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