日本機械学会論文集 A編
Online ISSN : 1884-8338
Print ISSN : 0387-5008
74 巻, 744 号
選択された号の論文の20件中1~20を表示しています
  • 齋藤 利之, 佐野 雄二, 神保 雅一, 末園 暢一, 北村 隆行
    2008 年 74 巻 744 号 p. 1045-1052
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    The Stress Corrosion Cracking (SCC) has been observed in a component of low carbon austenitic stainless steel and in a weld of Ni based alloy in the domestic Boiling Water Reactors (BWRs) and in a weld of Ni based alloy in the Pressurized Water Reactors (PWRs). It is important for stable operation with a high level of safety to adequately perform preventive maintenance. Since the laser peening improves residual stress near the surface region by irradiating laser pulses in water, it has been applied for operating BWR and PWR plants as a preventive maintenance against the SCC. The residual stress in the weld region of core shroud support of BWR before and after the laser peening were examined by a finite element analysis. The magnitude of stress intensity factor (K) for a crack with an arbitrary depth is calculated by using the stress distribution. The results show that the K after the laser peening is not larger than that before (as-welded condition) and there is no ill effect on the crack propagation. It is also predicted that the laser peening effectively prevents the propagation of a small crack.
  • 井口 克之, 多田 直哉, 清水 一郎
    2008 年 74 巻 744 号 p. 1053-1059
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    The distribution of static strain along the fillet on an upper deck of cylinder block and its dependency on the depth of thread engagement for cylinder head bolts were evaluated for a diesel engine by the finite element method. Since the fillet on upper deck is one of the critical parts in the cylinder block that may be cracked by stress and strain concentration, the static strain along the fillet was focused on in this study. In the model, the static tightening force of cylinder head bolts balanced with the total force acting on the cylinder block. A uniform surface pressure calculated by the total force divided by the contact area was given to the upper deck. The following results were obtained.
    The static strain along the fillet was dependent on the circumferential direction of cylinder and its value was varied with the depth of thread engagement for cylinder head bolts. The optimum depth of thread engagement was determined to be about 100 mm from the viewpoints of the overall magnitude of strain, the circumferential fluctuation of strain, the change rate of strain against the depth of thread engagement, and the length of cylinder head bolt. The calculated circumferential distribution of the static strain and the tightening force were compared with the measurement results under the optimum depth of thread engagement condition. Both results agreed well and this fact suggests that the present analysis is useful for optimizing the structural design of cylinder block for diesel engines.
  • 第1報, 数値解析的検討
    陳 玳〓, 小河 卓也, 尾崎 伸吾
    2008 年 74 巻 744 号 p. 1060-1067
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    In this paper, the crushing behaviour of hexagonal honeycomb structures with finite widths and heights subjected to in-plane compressive loading is studied by using the finite element method. It is found that stress-strain curves are clasiffied roughly into two types, which include both symmetric and asymmetric modes. They are influenced by ratio of thickness of cell wall, ratio of the work-hardening, and ratio of the yield stress. In addition, it is revealed that the deformation mechanism of the honeycomb structure with the finite width and the height can be explained by the unit model proposed by Klintworth (1988), even if the effect of the work-hardening is considered.
  • 第1報, 構造を剛体近似した場合
    石原 大輔, 窪田 篤司, 堀江 知義, 二保 知也, 吉村 忍
    2008 年 74 巻 744 号 p. 1068-1075
    発行日: 2008/08/25
    公開日: 2011/08/16
    ジャーナル フリー
    In this paper, a strongly coupled method for interaction of rigid body, incompressible viscous fluid and electrostatic field is developed. The present method is composed of monolithic and partitioned methods. The former solves structure-fluid interaction and the later solves interaction of electrostatic field and the other fields. The difference between the present method and conventional method is the introduction of the iterative solution procedure in the partitioned method. To demonstrate the fundamental performances of the present method, it is applied to simulate a micro membrane actuated by electrostatic force situated in air. The present result agrees well with the theoretical solution when the displacement of the rigid body is small. We also confirm that the iterative solution procedure makes the present method to be the strongly coupled method through the numerical example.
  • 古口 日出男, 浮須 和樹
    2008 年 74 巻 744 号 p. 1076-1082
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    Joint structures of piezoelectric and no piezoelectric materials are often seen in intelligent structures. Generally, stress singularity fields exist at a vertex in the joint structures. It is necessary to examine their reliability for maintaining the performance of structures. Stress singularity may reduce the reliability of intelligent materials. Hence, the order of singularity at the vertex in three-dimensional piezoelectric joints is investigated. In the present study, 3D-FEM eigen equation is formulated based on the principle of virtual work. Piezoelectric effect is incorporated into 3D-FEM formulated for eigen analysis in elastic joints. Then, the influence of wedge angle at the vertex in three-dimensional joints on the order of singularity was investigated and the range of wedge angle disappearing the singularity was presented. It was found that the number of the order of singularity in piezoelectric joints is larger than that in elastic joints, and the order of singularity relating to the piezoelectric effect only exists. The variations of singularity order with dielectric and piezoelectric constants in joints of a block PZT and a half Al were analyzed. It was found that their influence on the order of singularity was reverse and piezoelectric property controlled the variation of the order of singularity in the case where the ratios of piezoelectric and dielectric constants vary simultaneously.
  • 寺田 賢二郎, 犬飼 壮典, 平山 紀夫
    2008 年 74 巻 744 号 p. 1084-1094
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    A method of numerical material testing is developed for characterizing equivalent or macroscopic mechanical and/or other physical properties of composite materials with heterogeneous microstructures. The proposed method is prepared for testing on a variety of heterogeneous microstructures and nonlinear material behavior of constituents and their interfaces under various patterns of macroscopic loading. The numerical material testing in this method is intended to be carried out by means of the finite element method with a quasi-static implicit solution scheme in conjunction with the homogenization theory for periodic microstructures, i.e., unit cells.
  • 東郷 敬一郎, 伊東 悠, 島村 佳伸
    2008 年 74 巻 744 号 p. 1095-1103
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    This paper deals with a micromechanics model of particle-reinforced composites which can describe debonding damage of particles-matrix interface, matrix plasticity and particle size effect on deformation and damage. The Tohgo-Chou-Weng's incremental damage theory of particle-reinforced composites based on the Eshelby's equivalent inclusion method and Mori-Tanaka's mean field concept has been extended to consider the particle size effect by using the Nan-Clarke's simple method. The particle size effect on deformation is realized by introducing dislocation plasticity for stress-strain relation of in-situ matrix in composites, and the particle size effect on damage is described by a strain energy release rate criterion for particle-matrix interfacial debonding. Furthermore, for the composites containing particles of various sizes, the effect of a particle size distribution is incorporated into the model. Influence of the debonding damage and particle size on the stress-strain response of composites is discussed based on numerical results by the proposed model.
  • 小林 誠治, 松崎 亮介, 轟 章
    2008 年 74 巻 744 号 p. 1104-1110
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    Since CFRP structure becomes complicated due to adoption of integral molding, local molding faults such as under cure and dry spot are liable to occur. For solving this problem, it is demanded to measure the distribution of cure-degree of whole composite structure. In the present study, we propose a patch-type flexible matrix sensor based on permittivity measurements. Multiple electrodes and wirings are readily fabricated at one time using a photolithographihc process. Moreover, the sensor has only m+ n wirings for m× n sensors, and is thereby suitable for the multipoint cure monitoring. We also constructed the method of estimating degree of cure considering effect of frequency dependence of permittivity of resin and viscosity variation due to temperature change. Experiments of multipoint cure monitoring are carried out using a CFRP plate and an actual aircraft structure. As a result, we confirmed the effectiveness of this method by comparing with the conventional differential scanning calorimeter.
  • 國澤 鉄也, 侃慶 清
    2008 年 74 巻 744 号 p. 1111-1117
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    Several carbon blacks and carbon nanofiber were treated with heat at six hundred degree. The effect of reinforcement of rubber composites was investigated. The acidic functional groups in the filler surface decreased due to the heat treatment. The decrement of generation of CO and CO2 on carbon-base nanofillers was confirmed. The heat treatment of carbon-base nanofillers brought the increment of both storage modulus (E′) in viscoelasticity and tear strength for their rubber composites. The shapes of carbon nanofibers in rubber composite were observed by TEM and SEM photograph. The carbon nanofibers in rubber composites have been cut into about 1/5 of the original ones and they are oriented to the roll direction. In spite of small amount of isodine adsorption, the rubber composite with carbon nanofibers showed higher E′ than that with carbon blacks. Thus, it is indicated that the heat treatment of carbon-base nanofillers will be beneficial for improving reinforcement of rubber composites.
  • 齊藤 徹, 鈴木 裕士, 石橋 寿啓, 友田 陽
    2008 年 74 巻 744 号 p. 1118-1125
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    The residual stresses in a forged part made of an aluminum alloy with grain size of approximately 1.0 mm were determined by neutron diffraction where the oscillation method was employed. An optimal range of the oscillation is discussed from the relations between the gauge volume and the number of crystal grain. It is found that the stress measurement could be performed with the oscillation range of ±3 degrees if 1000 grains exist in a gauge volume. The influence of diffraction-plane reveals that adoption of (311) requires smaller oscillation angle than (111), (220) or (200). The hydrostatic tensile stress of about 100 MPa was observed inside the part, which was caused by thermal misfit strains caused during cooling after the heat treatment.
  • 水谷 淳之介, 西田 友久, 武藤 睦治, 川邑 正広, 今岡 亮, 佐藤 公彦
    2008 年 74 巻 744 号 p. 1126-1133
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    Fretting fatigue tests were carried out in order to investigate the effect of solid lubricant film on fretting fatigue strength of aluminum alloy (JIS A7N01). The ratio of fretting fatigue limit and plain fatigue limit (σwfw) for the present material without surface film was about 0.25, which was much lower than other aluminum alloys reported. Fretting fatigue strength was remarkably improved by using the solid lubricant film. The tangential force coefficient for the contact pad with solid lubricant film was significantly low compared to that for the contact pad without film. Heavy damage induced by the fretting on the specimen surface was observed for the case without solid lubricant film. On the other hand, only light damage can be found on the fretting surface for the case of the contact pad with solid lubricant film. Prevention of metal-to-metal contact and low tangential force coefficient due to solid lubricant film may be the main reasons for improved high fretting fatigue strength.
  • 上田 整, 石井 彰人, 近藤 宏憲, 井川 健
    2008 年 74 巻 744 号 p. 1134-1141
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    The thermoelectromechanical fracture of a piezoelectric material strip with two parallel cracks of different lengths under electric and thermal loadings is considered. The crack faces are supposed to be insulated thermally and electrically. Fourier transform techniques are used to reduce the mixed boundary value problems to two systems of singular integral equations. The singular integral equations are solved by using the Gauss-Jacobi integration formula. Numerical calculations are carried out, and detailed results are presented to illustrate the influence of the parameters of indicating the crack lengths, the crack location and the crack spacing on the stress and electric displacement intensity factors. The results for the temperature and thermal stress distributions are also included. From the numerical results, we can find that the normalized intensity factors are under the great influence of the geometric parameters. Especially, the interaction between two different length cracks is complicated.
  • 上田 整, 西村 直樹
    2008 年 74 巻 744 号 p. 1142-1149
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    A thermoelectroelastic problem of a functionally graded piezoelectric material (FGPM) strip containing an annular crack is solved. It is assumed that the thermoelectroelastic properties of the strip vary continuously along the thickness of the strip, and that the strip is under the thermoelectric loadings. The crack faces are supposed to be insulated thermally and electrically. By using the Hankel transform, the thermal and electromechanical problems are reduced to a singular integral equation and a system of singular integral equations, respectively. Numerical calculations are carried out, and detailed results are presented to illustrate the influence of the crack size, the crack location and the material nonhomogeneity on the stress and electric displacement intensity factors. It can be found that the normalized intensity factors are under the great influence of the geometric parameters and the effect of the material nonhomogeneity on the intensity factors depends on the geometric parameters.
  • 尾田 十八, 中川 茂憲, 田中 宏章, 大杉 乙允
    2008 年 74 巻 744 号 p. 1150-1155
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    It is important to know the impact fracture behaviors in the safety design of the laminated glass plate. However, the three-dimension analysis for the impact fracture behaviors of the laminated glass plate is not done over the current. In this research, the impact penetration fracture when the impact body collides with the center of the laminated glass plate is analyzed by PFC3D. It is the general three-dimensional program that uses the Distinct Element Method (DEM). DEM is suitable for the analysis of the fracture behavior of the non-individual body and the break-up body. The analytical results are compared with the experimental one and the validity of analytical results are checked. By this research, it is obvious that the penetration speed and the loss energy increase as the impact velocity, radius and mass of the impact body increase. Moreover, the relations between the parameters of impact body and fracture behavior are clarified.
  • 松田 伸也, 高橋 学, 尾上 拓史, 黄木 景二, 松下 正史, 岡部 永年, 大藤 弘明
    2008 年 74 巻 744 号 p. 1156-1163
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    In the present study, quench tests were carried out to characterize the fracture behavior of advanced pore-free SiC with damage tolerance during thermal shock. The residual strength of specimens after the quench tests was also measured. It is found that the critical temperature difference and the decrease in residual strength of this material are larger than those of conventional SiC. This is because the fracture is dominated only by flaw size since the wake zone is not generated during thermal shock with high strain rate. The critical temperature difference as well as the crack propagation is calculated with the aid of the unified theory of thermal shock.
  • 松尾 尚, 本間 紳浩, 松岡 三郎, 村上 敬宜
    2008 年 74 巻 744 号 p. 1164-1173
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    The effects of hydrogen and prestrain on the tensile properties of a low carbon steel plate JIS-SGP (0.078 C-0.012 Si-0.35 Mn) were investigated. The steel gas pipeline material JIS-SGP, which is one of candidates for hydrogen gas pipelines, is produced from the low carbon steel plate by plastic working and welding. In order to charge hydrogen, the virgin, and 10 and 20% prestrained specimens for tensile tests and hydrogen content measurements, machined from the low carbon steel plates, were immersed in a 20 mass% aqueous solution of ammonium thiocyanate at 313 K for 48 h. The hydrogen content increased by hydrogen charge after prestraining. Thermal desorption spectroscopy showed that the diffusible hydrogen contents are 0.38 ppm for the virgin hydrogen charged specimen, and 0.43 and 0.71 ppm for the 10 and 20% prestrained hydrogen charged specimens, respectively. The reduction of area was not affected by prestraining in the uncharged specimens, but it was affected by prestraining in the hydrogen charged specimens. The reduction of area was lower in the hydrogen charged specimens than in the uncharged specimens. The residual diffusible hydrogen contents after tensile test in the hydrogen charged specimens were between 0.38 and 0.71 ppm. The reduction of area decreased linearly with increasing hydrogen content in the hydrogen charged specimens. Scanning electron microscopy showed that cup-and-cone fracture occurred in both the uncharged and hydrogen charged specimens, and that the fracture surfaces were covered by dimples. Dimples were small in diameter and deep in the uncharged specimens, while they were large and shallow in the hydrogen charged specimens. Many voids were observed on the longitudinal section of tensile fracture specimen. The voids were elongated along the tensile axis in the uncharged specimens. On the other hand, the voids were elongated in the direction perpendicular to the tensile axis in the hydrogen charged specimens. It can be concluded that hydrogen enhanced slip deformation ahead of the void edge at the equatorial plane and results in a flat ellipsoidal void in the direction perpendicular to the tensile axis. This unique mechanism of development of dimples and voids in the hydrogen charged specimens should be noted to understand the basic mechanism of hydrogen embrittlement.
  • 村田 謙治, 水口 義久, 中村 正信, 山田 博之, 大柴 勝彦
    2008 年 74 巻 744 号 p. 1174-1180
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    It is important to collect basic data for which evaluates bone fracture healing on the living body. Evaluation of healing using pseudo-bone fracture model was examined by impact testing. The specimen was excited by an impulse hammer. Both the excitation signal of the impulse hammer and the response signal of the accelerometer were transmitted to FFT (Fast Fourier Transform) analyzer. The natural frequency was obtained by transfer function of the ratio of excitation and response signal. In this study, a pig's femur was substituted for a human bone and the natural frequency was measured. Furthermore, the states of bone fracture or bone fracture healing were imitated by using a pig's femur which cut deeply from the end or cut deeply from the outside diameter. This study examined how the specimen's natural frequency varied depending on the defects of pig femur. As a result, it was clarified the possibility that could evaluate bone fracture healing by measuring the natural frequency of bone.
  • 荒木 邦成, 嘉本 大五郎, 松岡 信一
    2008 年 74 巻 744 号 p. 1181-1183
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    To comply with energy saving, vacuum insulation panels (VIP) have been used in low temperature application in some years now. And for more high temperature, the material composition and process of VIP were reviewed, the SUS foil was adopted as packaging material, and soluble polyimide was developed as the thermo compression bonding material for high temperature VIP at 150°C. To lower the glass-transition temperature (Tg) under 200°C for the thermo compression bonding (Max230°C), we elaborated the new soluble polyimide using aliphatic diamine copolymer, and controlled Tg to about 176°C. By making from trial VIP and evaluations, it was possible to be maintain high performance concerning coefficient of thermal conductivity : λ<8 [×10-3W/ (m·K)] at 150°C.
  • 松岡 信一, 中川 高則, 村井 勉
    2008 年 74 巻 744 号 p. 1184-1185
    発行日: 2008/08/25
    公開日: 2011/03/02
    ジャーナル フリー
    Magnesium alloy is one of the light metallic materials which is utilized in industry, but it is difficult to do its plastic working in the ordinary temperature. After preforming to AZ31 magnesium alloy thin plate, the material has a performance of high drawing greatly. In this study, preforming is rolling processing. The preforming material has more high drawing as ratio of reduction in thickness increases, e.g. high preforming material (reduction in thickness : 34%×2) is able to be formed under temperature at 100°C.
  • 2008 年 74 巻 744 号 p. 1186
    発行日: 2008年
    公開日: 2011/03/02
    ジャーナル フリー
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