著者

浜田 実 渋谷 陽二

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.50, no.452, pp.584-592, 1984-04-25

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複数の自由縁の円孔を持つ円板の曲げ問題の解法として,極座標に対する重調和方程式の一般解を繰返し用いる方法を提案し,これにより,偏心位置に1円孔または対称位置に等大2円孔を持つ円板の外縁に一様曲げモーメントが作用する場合と,中央集中荷重が作用する場合の解を求める.また有限要素法と実験による結果と本解とを比較することにより,本解の妥当性を確かめる.

著者

久森 紀之 野末 章 木村 雄二

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.67, no.657, pp.844-851, 2001-05-25

被引用文献数

2

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High-temperature and high-pressure water corrosion behaviors of Y_2O_3 doped Zirconia (ZrO_2) were investigated in term of with the microstructural changes, residual strength characteristics and tetragonal to monoclinic phase transformation. Sintered ZrO_2 ceramics bodies with 2, 3, 4, 6 and 8 mol% Y_2O_3 doped ZrO_2 were made using a pressure less sintering method at 1 450℃, respectively. These ZrO_2 ceramics were corroded in high-temperature and high-pressure water condition such as 150℃〜300℃. Corrosion damage of the decrease Y_2O_3 dope ZrO_2 ceramics occurred preferentially on ZrO_2 particle after long-term immersion in high-temperature and high-pressure water environment. The tetragonal to monoclinic phase transformation occurred in decrease Y_2O_3 doped tetragonal ZrO_2 ceramics due to high-temperature and high-pressure water corrosion. For improvement of the corrosion characteristics (thermal stability) of the ZrO_2 ceramics, are important increasing the Y_2O_3 doped within a range in which no remarkable residual strength degradation is recognized. CeO_2 doped ZrO_2 ceramics were useful to improvement the thermal stability of Y_2O_3 doped ZrO_2 without loss of the fracture strength. CeO_2 doped ZrO_2 ceramics also have superior residual strength characteristics compared to Y-ZrO_2 ceramics. In addition design concepts used to obtain water-corrosion-resistant high strength and high toughness ZrO_2 ceramics were proposed.

著者

木村 成竹 泉 聡志 酒井 信介

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.73, no.734, pp.1105-1110, 2007-10-25

被引用文献数

1 4

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A spring washer is widely used as a method for preventing loosening. However, experimental results presented by Sakai and Yamamoto et al., show that the performance of a spring washer as a loosening prevention mechanism is at best equal to that of a washer-less joint, if not worse. In this paper we analyzed loosening under shear loading and as a result were able to explain the mechanism that accelerates loosening in the framework of the three-dimensional finite element method (FEM). A spring washer causes non-uniformity of contact pressure at the washer interfaces, because of its asymmetric shape. When a bolted joint with a spring washer is subjected to shear loading, sticking area on the contact surfaces of the spring washer is limited to two corner points before the bearing surface undergoes gross slip. One of these points is on the upper surface of the spring washer and the other is on the lower surface. In this situation the nut rotation around these sticking points results in drastic loosening. We also conducted comparative simulation with Sakai's experimental results. Compared with experimental results, the bolted joint with the spring washer is easy to loosen according to the simulation results. It is believed that the difference comes from the spring washer's edge cutting into the contact surface of the nut, something not included in this simulation.

著者

丸山 俊則 田口 真 岸田 和人 熊本 秀喜 吉川 孝男

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.67, no.664, pp.1948-1954, 2001-12-25

参考文献数

8

被引用文献数

3 3

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In these days, crashworthiness design has been required more frequently in rail vehicle. The results of static strength test of an end underframe that absorbs most of the crash energy were presented, as well as numerical simulations. By comparing both results, the numerical simulations were found to be adequately accurate. Then, a new and highly crashworthy structure was proposed. Both of the test and the numerical simulation confirmed that the structure worked well to absorb the crash energy. Further, effects of welding strength, geometrical initial imperfection, and strain rate on the crashworthiness were discussed. Especially, strain rate effect of materials is important to evaluate crashworthiness accurately.

著者

荒井 正行 佐久間 俊雄 岩田 宇一 山田 隆之 中村 一義 岸本 喜久雄

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.66, no.641, pp.144-150, 2000-01-25

被引用文献数

1 3

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The surfaces of many industrial products, such as a holl drill, gas turbine engine and so on, are coated with diamond and ceramic material for improving the material properties.On the other hand, the surface may accumulate an oxidation layer by reaction of oxygen with inceasing time.These Common damage, in service, is "delamination".It is known that the delamiation will be caused by compressive stress in these coating layer which is generated by vibration and fatigue loading for industrial coating, and volume expansion for oxidation.The actual coating delamination process as follow had been clarified by many studies.The coating layer is buckled locally by compressive loadingand is then delaminated along the substrate.The aim of this study is to clarify the coating delamination mechanism under compressive stress by observing continuously buckling and delaminating process in the coating layer, which is modelled by engineering plastic in this study. The delamination evaluation method is proposed based on an interface mechanics, and an accuracy of the evaluation is examined using finite element analysis.Finally, the proposed evaluation are applied to the experimental results obtained by this study.

著者

高尻 雅之 白川 寿照 宮崎 康次 塚本 寛

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.72, no.723, pp.1793-1798, 2006-11-25

参考文献数

27

被引用文献数

8

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n-type bismuth-telluride thin films are fabricated by flash evaporation method. Effects of hydrogen annealing on the thin films are investigated for potential application in micro thermoelectric devices. The thin films are grown up to 1 μm on a glass substrate by flash evaporation method. The hydrogen annealing is carried out in the temperature range between 200-350℃ on an atmospheric pressure. The electrical resistivity and Seebeck coefficient are measured at room temperature. Both the electrical resistivity and Seebeck coefficient are improved by the treatment of hydrogen annealing, then the power factor of the n-type bismuth-telluride thin film reaches 8.8μW・cm^<-1>・K^2 at annealing temperature of 350℃. The structure of the thin films, which is composition and crystallinity, is studied by electron probe micro analyzer and X-ray diffraction pattern, respectively. The composition of bismuth-telluride thin films is relativity constant until higher annealing temperature. The X-ray diffraction patterns indicate that the crystallinity of the thin films is improved as higher annealing temperature.

著者

今井 康文 森田 英毅 高瀬 徹 古賀 博之

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.55, no.509, pp.147-151, 1989-01-25

被引用文献数

7 7

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Time-dependent thermal stress singularities at a semi-infinite crack tip associated with a transient temperature field have been analyzed on an infinite plate with a point heat source near the crack tip. As the heating begins, a mode I singularity increases gradually with time, but, after showing its maximum, decreases to be negative. This singularity variation causes a crack to start growing at some instance, but soon after to stop. That is, crack growth may be controlled, which is desirable for a cutting device for brittle materials. Deflection of a heating point from a crack line results in a mode II stress singularity, which also leads a crack to swerve from the original crack line. In an experiment using glass plates, a crack was successfully controlled to grow and also to branch in any angle toward the heat source as long as the heating location was kept appropriately apart from the crack tip.

著者

徳田 貴志 河合 浩志 岡田 裕 福井 泰好

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.76, no.770, pp.1255-1262, 2010-10-25

被引用文献数

3

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Although three-dimensional finite element analysis has become a common tool in the industries to perform their design analyses, there still exist some difficulties in performing three-dimensional fracture analyses. One of them is that although automatic mesh generation techniques are available for tetrahedral finite elements, hexahedral finite elements are commonly used in three-dimensional crack analyses. The other is that the analysis models tend to be large in their scales. Therefore performing a three-dimensional fracture analysis takes much manual labor in the analysis model generation processes and computational time. In present research, the authors have been developing a fracture mechanics analysis system that minimizes the manual labor. The key components in the analysis system are a mesh generation software and the virtual crack closure-integral method (VCCM) for the second-order tetrahedral finite element to evaluate the crack parameters (the energy release rates and the stress intensity factors). Based on them, the software system was carefully designed to handle large scale analysis model. In this paper, as the first report, the outlines of the system and the finite element model procedures are described.

著者

西岡 俊久 小林 豊 Epstein S. J.

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.59, no.561, pp.1319-1326, 1993-05-25

被引用文献数

2

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Finite element simulation was carried out for inhomogeneous elastic-plastic fracture specimens, which consist of A533B steel and HT80 steel. These two materials have considerably different yield stresses, although their elastic properties are exactly the same. The nonlinear fracture parameter, T^* integral, was extended for inhomogeneous multilayer materials. The T^* integral for inhomogeneous materials demonstrates excellent path independence, even in the stages of large plastic deformations around the crack tip and the material interface. Numerically generated moire fringe patterns are in good agreement with experimentally recorded patterns. The shapes of plastic zones appearing in the specimens reveal large inhomogeneity effects.

著者

西岡 俊久 西 正己 藤本 岳洋 坂倉 慧悟 Epstein S. Jonathan

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.59, no.559, pp.558-565, 1993-03-25

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In order to investigate inhomogeneity effects in elastic-plastic fracture, A533B steel and HT80 steel, which have considerably different yield stresses, were chosen. The moire interferometry was used for direct measurements of the crack-tip behavior in the homogeneous CT specimens of A533B and HT80, and in electron-beam-welded inhomogeneous CT specimens of these two materials. Two-dimensional moire gratings with relatively low frequency of 300 lines/mm were used to follow large plastic deformations. The near-tip deformations were compared with the corresponding HRR singular fields. Large inhomogeneity effects were observed in the moire fringe patterns as plastic deformations proceed.

著者

小川 和洋 庄子 哲雄 青木 久彦 藤田 範生 鳥越 泰治

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.66, no.647, pp.1370-1376, 2000-07-25

被引用文献数

4 2

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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.

著者

長嶋 利夫 大本 洋平 谷 周一

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.70, no.691, pp.383-390, 2004-03-25

被引用文献数

1

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Conventional FEM requires that the boundary of the element just matches the crack line to perform stress analyses of structures containing cracks in the field of fracture mechanics. These modeling processes are rather complicated and cannot be performed easily even if the automatic mesh generation technique is utilized. Recently, Belytschko et al. proposed the extended finite element method (X-FEM) based on the concept of partition of unity, and applied this method to the evaluation of the stress intensity factors and perfoming the crack extension simulation. The X-FEM can be used to simplify the modeling of continua containing several cracks and hence perform effective stress analyses related to fracture mechanics. This paper describes the two-dimensional thermal stress analysis of structures containing cracks. Stress intensity factors having mixed modes coupled with mode-I and mode-II are evaluated by M_1-integral method in conjunction with X-FEM. This method is examined in numerical examples of elastic and thermo elastic analyses. The numerical results show that X-FEM is an effective method for performing thermal stress analyses and evaluating stress intensity factors.

著者

長嶋 利夫 三浦 直樹

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.72, no.719, pp.974-981, 2006-07-25

被引用文献数

2

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The extended finite element method (X-FEM), which can model the domain without explicitly meshing the crack surface, can be used to perform stress analyses for efficiently solving fracture mechanics problems. In this study, the constraint condition enforcement for X FEM analysis considering symmetry is presented. Since the interpolation functions utilized in X FEM analysis include the enrichment basis functions, the freedoms of the node on the symmetric plane should be constrained properly in X-FEM model with symmetric conditions. Moreover evaluation of the energy release rate by the domain integral method should be performed considering symmetry conditions. In this paper the constraint conditions for three dimensional X FEM analysis considering symmetric conditions are summarized and the numerical examples using symmetric X FEM models are shown. The proposed procedure can be used to perform efficient X FEM analyses of practical fracture problems.

著者

許 金泉 武藤 睦治 付 列東

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.68, no.672, pp.1259-1265, 2002-08-25

被引用文献数

1 7

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The theoretical solution of a concentrated force on the free surface of a coating material is deduced by introducing the infinite series mirror points of the load point and applying the Dirichlet's uniqueness theorem. In this study, the two dimensional solution is deduced in details by using the infinite series of the Goursat's stress function corresponding to every mirror point. It is found that the stress function corresponding to a higher order mirror point can be determined from that corresponding to a lower one, therefore, all the stress functions can be determined from that corresponding to the first order mirror point which is in fact the stress function for concentrated forces on the free surface of a semi-infinite body. It is also found that the contribution of the stress function to stress distribution decreases as the increasing of the corresponding order of the mirror point. It is confirmed that only the stress functions corresponding to the first several mirror points have an influence on the accuracy of theoretical solution. This theoretical solution can be expected to be very useful in evaluating the strength of coating materials or other surface modificated materials.

著者

岸田 路也 佐々木 一彰 町野 史郎

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.57, no.533, pp.181-187, 1991-01-25

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This paper describes the accuracy of surface integrals in the indirect boundary integral method containing singular integrals. Here, the surface integral is carried out directly and numerically by the use of Simpson's and Legendre-Gauss's quadrature formulae. Also, the line integral, obtained by applying Gauss-Ostrogradskii's transformation to the surface integral, is examined. The accuracy is evaluated by the convergence behaviors of surface and line integrals and by the comparison with the analytically obtained integral values.

著者

松原 雅昭 伊澤 悟 平尾 典盟 毒島 康二 小山 哲 町田 康治 川田 大介 坂本 賢治 根津 紀久雄

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.67, no.659, pp.1218-1222, 2001-07-25

参考文献数

11

被引用文献数

1 1

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The authors developed a new testing equipment for studying statically indeterminate fracture mechanics. Its development purpose is to clarify load history-dependency of the collapse load. The equipment has two actuators orthogonalized. The horizontal actuator applies the axial force and the perpendicular one does the bending moment. In the experiment for examining the effect of load hysteresis on the collapse load, both actuators can keep the preceding load to the constant load value, until axial force and bending load reach the theory collapse point. The actuators can apply the following load under the displacement control in the experiment. The performance of the equipment was confirmed by demonstration tests using single-edge notched specimens of SUS 304 steel. The experimental result clarified load historydependency on collapse load in SUS 304 single-edge notched member subjected to combined tension and bending.

著者

佐藤 裕久 菊池 亘 鈴木 英

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.63, no.616, pp.2618-2623, 1997-12-25

被引用文献数

7 3

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An unsteady-wave-sensing-system (UWSS) is developed for evaluating the wave propagation characteristics of polymethyl methacrylate (PMMA) for loading-reloading-unloading waves using plate-impact experiments and three PVDF gauges. By applying the UWSS, stress, particle-velocity, strain and two kinds of phase velocities at one location in the PMMA are determined as functions of time. The phase velocities U^σ associated with the stress profiles are generally different from the other phase velocities U^υ associated with the particle-velocity profiles. From loading to reloading are transitions very near from the Hugoniot in the stress-strain plane, but from reloading to unloading are transitions upward off the Hugoniot. In the region of our experimental stress, PMMA does not behave as liquid and the Hugoniot of PMMA is not effective for the loading-history-characteristics.

著者

宇賀地 弘和 奥 達雄 石山 新太郎 衛藤 基邦

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.62, no.593, pp.10-17, 1996-01-25

参考文献数

9

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Since carbon fiber reinforced carbon composite (C/C composite) materials have good mechanical properties at high temperature and low radioactivity under irradiated conditions, they have been used as the plasma-facing components in fusion facilities. Efficient utilization of these mechanical properties will lead to the use of c/c composite materials, these materials are expected for use as control rods for gas-cooled rectors and irradiating capsules. In the case of using c/c composite materials as the structural components, it is very important to evaluate the mechnical and thermal properties as well as fracture behavior. For structural components used in a reactor core, it is necessary to evaluate neutron-irradiation effects on these materials. However evaluation of these effects has been difficult, thus data on irradiated c/c composite materials are lacking. In this study, three kinds of c/c composite (CC-312, CX2002U and MCI) made of different fiber materials were irradiated under the condition of maximum neutron fluence of 2×10^<25> n/m^2 and maximum irradiating temperature of 1200℃, and the relationship between change of mechanical properties due to irradiation and the constitution of c/c composite materials was evaluated. In the case of CC-312 made of PAN fiber, Young's modulus changed slightly and bending strength after irradiation. In the case of CX2002U made of rayon fiber, Young's modulus and bending strength increased after irradiation. In the case of MCI made of pitch fiber, Young's modulus increased after irradiation, but bending strength decreased slightly after irradiation. These results enable the elucidation of the relationship between properties of fiber meterials and irradiation effect on c/c composite materials.

著者

山崎 友裕 西野 博満 片山 大希

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.76, no.762, pp.145-150, 2010-02-25

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Electromagnetic acoustic transducer (EMAT) is applied to resin cure monitoring in manufacturing process of fiber reinforced plastic (FRP) by resin transfer molding (RTM) method. The RTM is suitable for fabrication of FRP products of three-dimensional complex shape. In order to reduce the cost by minimizing the cycle time, cure monitoring is required. Authors have already ensured that the EMAT can detect the resin flow front in RTM process by monitoring the change in reflection coefficient at mold surface due to resin impregnation. The reflection factor is also affected by the resin viscosity. In this study, during the curing process, we measure the attenuation coefficient of standing wave introduced in the mold. Results are compared with impedance of dielectric sensor located inside the mold, showing that the degree of cure can be evaluated by EMAT at outer surface of the mold.

著者

座古 勝 倉敷 哲生

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.62, no.594, pp.583-588, 1996-02-25

被引用文献数

1

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When an explosion occurs in chemical plants, the explosion pressure leads to collapse of pipes and equipment. Even if pipes are not destroyed immediately by the explosion pressure, the cumulative damage caused by the sequential explosion pressure will bring about collapse. Therefore, the disaster simulation program, which takes the cumulative damage into consideration, has been developed. In this program, three-dimensional explosion pressure applied to pipes can be calculated, and the equivalent stress acting on the connecting bolts of pipes can be analyzed. The cumulative damage is estimated by use of the obtained stress, Manson-Coffin's rule and Miner's rule. As an example, the cumulative damage over time for pipes in a model plant has been analyzed. As a result, it is shown that the proposed computer program is very useful for reliability evaluation and installation of pipes in chemical plants.