著者

三木田 嘉男 中林 一朗

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集A編 (ISSN:03875008)

巻号頁・発行日

vol.53, no.487, pp.475-482, 1987

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Quench cracking and distortion are generally considered to occur under united thermal and transformational stresses. In this paper quench residual stresses were examined by using a S 55 C steel bar. Various polyalkylene glycol (PAG) solutions and oil were prepared for the quench cooling solutions. The micro structure of the test piece was observed with a metallurgical microscope. The residual stresses caused by quenching were measured by Sachs' method. Considerable tensile and compressive stresses existed on the surface and in the center of the steel. The distribution of stresses and the hardness were related to the PAG content and could be explained clearly by the quench cooling rate.

著者

石塚 丈洋

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.65, no.635, pp.1520-1527, 1999-07-25

被引用文献数

1

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For the purpose of investigating the macroscopic and microscopic elastoplastic deformation behavior of two-phase composites : W-Ni-Fe alloys, the constitutive relations of W-Ni-Fe alloy and its microconstituents were measured by the Hopkinson pressure bar testing and usual compression testing, and then the elastoplastic deformation behavior of W-Ni-Fe alloys in uniaxial compression was analyzed using the micromechanics-based analysis method. The main conclusions are summarized as follows ; (1) The work hardening tendency of W-Ni-Fe alloy is in keeping with that of pure tungsten particle phase which is B.C.C. metal. (2) Measured flow stresses of W-Ni-Fe alloy under high strain rate loading are smaller than analyzed ones, due to local failure in the matrix phase of W-Ni-Fe alloy. (3) The compressive residual stresses in the particle phase are produced at the cooling stage in sintering. (4) The micromechanics-based analysis method can precisely analyze the elastoplastic deformation behavior of two-phase composites until large deformation.

著者

石塚 丈洋

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.64, no.625, pp.2308-2314, 1998-09-25

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Numerical simulations are effective approach for the safety design of machines and structures subjected to impact loading and the investigation of impact phenomena. Dynamic mechanical properties which accurately model the response of materials to impact loading are necessary for such numerical simulations. In this research, the equation of state and failure criteria are measured by plate impact testing, and then the accuracy of these measured dynamic mechanical properties is evaluated based on numerical simulation results. Followings are useful information obtained. (1) The equation of state and failure criteria measured by plate impact testing are sufficiently accurate for numerical simulations. (2) Pure W which is the brittle metal, follows stress-dependent failure criterion. (3) W-Ni-Fe alloys which are the ductile metals, follow time-dependent failure criterion. (4) W-Ni-Fe alloy has the lower critical value for spall failure than its matrix phase. (5) The failure strains of W-Ni-Fe alloys depend on the state of stress.

著者

福田 収一 渡 秀二 堀川 浩甫

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.47, no.416, pp.384-390, 1981-04-25

被引用文献数

1 5

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溶接残留応力が疲労き裂伝ぱにおよぼす影響を80kg/mm^2級高張力剛を用い, き裂開閉口現象に注目して実験的に検討した. すなわち, サブマージ溶接した縦突合わせ溶接継手試験片と素材試験片における横われを想定した中央切欠きからの疲労き裂伝ぱをしらべ, 溶接景趣試験片における残留応力の影響も素材試験片における応力比の影響も有効応力拡大係数範囲ΔK_<eff>を用いれば統一的な定量的評価が可能であることを明らかにした.

著者

北村 隆行 屋代 如月 大谷 隆一

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.62, no.600, pp.1813-1819, 1996-08-25

被引用文献数

5

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In order to elucidate the mechanism of deformation and fracture of microcomponents, numerical simulations are conducted for nanoscopic wire and film of nickel without lattice defects using molecular dynamics on the basis of the EAM (embedded atom method) potential. Applying a periodic boundary, large as well as small materials are subjected to a tensile strain along the [001] direction of the FCC (face-centered cubic) lattice. Here, the traverse stresses, σ_<xx> and σ_<yy>, in the former are kept at zero during the tension. The yield is brought about by the crystallographic slips on the (111) planes and there is little difference in the yield stresses among the wire, film and bulk. The slips continue to take place on multiple (111) planes and the plastic deformation leads to ductile fracture. Then, the displacement in the traverse direction on the cell boundaries of bulk is fixed in order to investigate the effect of constraint. It shows brittle fracture due to cleavage cracking. this implies that the constraint, which may be introduced by local inhomogeneity of the material, brings about early crack nucleation and reduces the ductility of matcrials without lattice imperfection.

著者

廣江 哲幸 松尾 日出男 藤原 和人 宮田 政信 松本 繁明 安部 尊之

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.62, no.601, pp.2026-2031, 1996-09-25

被引用文献数

3

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Spall tests for three kinds of materials (A12024, SS41, Cu) are conducted using a newly developed testing device. This experimental assembly generates triangular stress waves with various gradients-in plate specimens (50×50×20mm) by direct explosive loadings. The relationship between measured spall layer thicknesses (5-15mm)and the explosive (PETN) thicknesses indicate that a time dependence exists in spall phenomena of the metals. A computer program with a cumulative damage model was constructed, which has reproduced the basic characteristics of the observed failure in the metals. It is known that the stress wave reflected at the free surface can be prevented from reaching the specimen plate by spallation of the momentum trap or spall plate, which is mounted in contact with the specimen. The following spall test results for A12024 have verified this effect and the numerical analysis also has simulated the phenomena successfully.

著者

宮原 健介 松岡 三郎 長島 伸夫 三島 周三

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.61, no.590, pp.2321-2328, 1995-10-25

被引用文献数

13 12

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A nanoindentation hardness apparatus was developed on the basis of an atomic force microscope to obtain both an indentation curve and an indentation image. Newly devised features were to use a lever which has a three-sided pyramidal diamond tip at the central part of the lever, to measure the vertical displacement at the center of the lever and to add an actuator for controlling the force. The ultra-microhardness values of gold, SUS403 steel and SNCM439 steel measured at the indentation forces between 2.6×10^3 and 3.5×10^3 μN using the nanoindentation hardness apparatus agreed with the macrohardness values measured at the force of 4.9 or 9.8 N using the conventional Vickers hardness apparatus. However, the ultra-microhardness increased with decreasing indentation force. This behavior was explained considering the elastic-plastic conditions of the specimens.

著者

片平 和俊 鈴木 秀人 岡田 昌巳 友田 陽 岩野 利彦

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.64, no.622, pp.1475-1480, 1998-06-25

被引用文献数

7 1

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To improve the fatigue reliability for SMn 435 steel by an environmentally sound surface modification, the influence of the modification on fracture mechanism was studied experimentally. The fatigue properties of SMn 435 are found to be obviously improved by gas soft-nitriding, so that they can no longer be estimated by using a concept of "S-N Globe"which has successfully been applied to many surface-treated materials. The detailed observations have revealed that fatigue crack initiation in a gas soft-nitrided SMn 435 specimen occurs in a hardened region near surface not in a subsurface region with virgin microstructure. The crack initiation is attributable to cyclic plastic deformation in the subsurface region. Such a crack initiation mechanism is different from that previously observed in other surface treated materials, explaining the reason why the S-N Globe concept can not be applied to the present case.

著者

宮川 浩臣 西谷 弘信

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.51, no.462, pp.445-449, 1985-02-25

被引用文献数

3 1

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This paper is concerned with the beneficial effects due to additional holes or indentations. Two indentations facing each other with the tip of a crack is especially effective in retardation of crack propagation. The effects of the indentations can be estimated approximately from the existence of residual stresses produced by the indentations.

著者

酒井 達雄 中間 好信

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.563, pp.1656-1662, 1993-07-25

被引用文献数

1 1

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Many kinds of engineering ceramics have been developed and used as parts of mechanical structures. These ceramics are often used as machine parts which are exposed to elevated temperatures. The strength distribution of those materials significantly depends upon the temperature. In this study, distribution characteristics of the flexural strength for alumina ceramics were examined at the temperatures of room temperature (RT), 800℃, 1000℃ and 1200℃, respectively. Based on the temperature dependence of distribution parameters, the Probability-Strength-Temperature characteristics were quantitatively analysed. An analytical model for the temperature dependence of the strength distribution was finally proposed by introducing the defect sensitivity and its temperature dependence. Analytical results thus obtained were in good agreement with the experimental aspect of the strength distributions.

著者

中川 博文 北村 純一 近藤 徹 飯沼 和三 高橋 賞

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.61, no.582, pp.466-471, 1995-02-25

被引用文献数

4

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The efficiency of visual biofeedback (VFB) training method using a Photoelastic imaging system on restoring and stabilizing a standing position of stroke patients was investigated. As a stroke group, seven hemiplegics were selected with the mean of 57 year-old. Twelve age-matched healthy subjects were selected as controls. The subjects were asked to stand upright on the photoelastic apparatus and to gaze at a marker 1.5M distant on the wall. Then, VFB training was performed for ten minutes by self recognition of his own pressure patterns which were produced by photoelastic system and were monitored on a TV screen. The patterns were photographed in each different condition such as in a standing position with eyes open or closed before and after l0-minute-training with VFB, and were comparatively analysed. The results showed that (1) the ratio of affected side to unaffected definded by the number of first fringes produced increased significantly after VFB up to the control level, (2) the ratio of body weight loading on the affected side to unaffected was significantly increased after VFB, and (3) the position of center of contact pressure on the longitudinal axis of an affected sole was found to be significantly more posteriorly sifted than in the control and was remained unchanged after VFB. In conclusion, the VFB method using a photoelastic imaging system may be useful to enhance visual-contact motor balancing functions in patients with hemiplegics and also to study a restoring process of neurological impairment leading to a postural problem.

著者

駒井 謙治郎

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 = Transactions of the Japan Society of Mechanical Engineers. A (ISSN:03875008)

巻号頁・発行日

vol.69, no.687, pp.1521-1523, 2003-11-25

著者

江原 隆一郎

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集A編 (ISSN:03875008)

巻号頁・発行日

vol.59, no.557, pp.1-11, 1993

被引用文献数

1 3

著者

江上 登 加賀谷 忠治 井上 宣之 竹下 弘秋 水谷 肇

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.650, pp.1936-1942, 2000-10-25

被引用文献数

12 21 7

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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 △K_eff, as well as the fatigue crack initiation life N_i and crack failure life N_f of specimens. The results show specimens with hybird surface modification are effective in the prevention of fatigue crack initiation and fatigue crack propagation.

著者

古賀 達蔵 遠藤 修司

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.45, no.393, pp.481-488, 1979-05-25

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静的端末荷重が作用する周方向に作用する閉じた円筒かくの境界値問題について,Kirchhoff-Loveの仮定に基づく種々の線形かく理論の解の相違と精度を調べ,こてんかく理論としてよく知られている多くの理論が基本仮定の誤差の範囲内で正しい一次近似解を与えることを示す.また,実用的な簡単な形の閉形解を求めて,解の重要な諸性質を明らかにする.

著者

三牧 敏太郎 丸山 和士 井之脇 隆一

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.61, no.584, pp.835-841, 1995-04-25

被引用文献数

4 1

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For a horizontal well or an extended reach well, which is promising for well construction in . future, a well casing is subjected to local wear of wall thickness on its inside surface due to rotational contact with tool joint or drill pipe during drilling. Collapse strength of worn casing is analyzed as an unstable problem by the elastic-plastic finite-element method (FEM) and the decrease ratio of collapse strength due to casing wear is formulated by nonlinear programming using parameters of the wear shape. The elastic-plastic FEM is fully applicable as values calculated by the FEM program agree well with those of experiments. It was found that the decrease ratio of collapse strength of a worn casing is linearly proportional to the decrease ratio of wall thickness in both modes of plastic collapse and elastic collapse, and that the apical angle of the wear shape has a slight influence on collapse strength.

著者

徳田 正孝 大橋 義夫 大橋 義夫

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.48, no.426, pp.239-247, 1982-02-25

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多結晶金属の塑性異方性の発達に関する基本的特性,たとえばおくれ効果,記憶減退性,予ひずみの影響の飽和などは,理想化された簡単な多結晶モデルを用いて説明される.とくに単結晶間の相互作用により生じる内部応力は,ここで支配的な役割を果たす.さらに,このモデルによる計算結果は,ひずみ経路の折れ点後あるいはひずみ経路の曲率部分にみられる一連の複雑な塑性変形挙動を定性的な意味で的確に表した.

著者

佐藤 一志 粟山 仁 橋田 俊之 高橋 秀明

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.56, no.526, pp.1400-1405, 1990-06-25

被引用文献数

2 2

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The J-integral-based technique for measuring strain-softening curves is applied to determine the fracture toughness of granite. The measuring method has been recently proposed by Li for concrete. This method provides information on the fracture process zone formation and can be used for fracture toughness determination in strain-softening materials. CT specimens of three different sizes, 1.5inch, 2.5inch and 6inch CT were tested to examine the specimen size effect of measured strain-softening curves. Strain-softening curves measured on 2.5inch CT specimens are shown to be in good agreement with that determined from 6 inch CT specimens, indicating the possibility of determining the valid fracture toughness value by means of the J-integral-based technique. The test results for 1.5inch CT specimens, however, yield a lower fracture toughness value than that obtained on the other specimen sizes, suggesting the need of detailed investigations on specimen size requirements for the reliable use of subsized specimens. Finally, the strain-softening curves obtained by the J-based technique are compared with existing data determined by uniaxial tensile tests on several types of granite.

著者

柏村 孝義 白鳥 正樹 于 強 国府田 勲

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.601, pp.2180-2185, 1996-09-25

被引用文献数

23 10

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The authors proposed a new practical optimum design method that consists of two steps: the design of experiments and mathematical programming. The design of experiments is used to generate approximate evaluation functions for the controlling behavior depending on the changes in design variables of an object structure, by a series of finite element analyses (FEA). Based upon an orthogonal array of a combination of design variables, effects of the design variables can be calculated by a relatively small number of FEA, and then the approximate evaluation functions are generated by those effects based upon analysis of variance. The evaluation functions can also be used as direct tools for estimating the behavior of design structure. Finally, a successive quadratic programming (SQP) method is employed to solve the optimization problem of the approximate evaluation functions. It is confirmed that the proposed method can be used for almost all kinds of the nonlinear problems including the impact behavior of structures, and that it can be carried out in much smaller number of FEA than the other existing methods. As an example, the present method was used to solve an optimum design problem of an automobile seat frame subjected to impact loading. It was found that the present method is a very effective and powerful tool for the optimum design of various practical design problems.現在提案されている最適化設計のシステムの多くは複雑,効率が悪いという問題を持っている.本論文では,実験計画法,構造解析および数理計画法を組み合わせた実用的で効率の良い最適化方法を提案する.

著者

高橋 寛 塩野 功 大場 博

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.49, no.443, pp.876-882, 1983-07-25

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アルミニウム円管の引張内圧複合負荷試験により,応力平面(π平面)第一印象における比例負荷試験を行い,各方向の応力ひずみ曲線を,単一の曲線に統一するための相当応力相当ひずみを求め,相当応力一定の曲面が降伏曲面であることの実験的検証を行った.