著者

東藤 貢 高橋 清 JAR BenP.Y. BEGUELIN Philippe

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.631, pp.432-438, 1999-03-25

参考文献数

21

被引用文献数

1 1

---

Toughening mechanisms of three types of rubber toughened poly (methyl methacrylate) (RT-PMMA) were investigated under mode I loading condition by optical and electron microscopies in conjunction with the quantitative evaluation of mode I fracture toughness. Polarized optical microscopy clearly exhibited damage zone development ahead of a crack-tip of the RT-PMMAs. The three RT-PMMAs revealed different shapes of the damage zone. Transmission electron microscopy exhibited microcrazes nucleated in the equator of rubber particles within the damage zones. Extensive deformation of rubber particles corresponding to localized shear yielding of the PMMA matrix was also found in a region close to a propagating crack-tip. In addition, cavitation of rubber particles was observed in the vicinity of the crack. It is therefore understood that the toughening of the RT-PMMAs is due to energy dissipation caused by the microdamage formations such as microcrazing, matrix shear deformation and rubber particle cavitation ahead of the crack-tip.

著者

鈴木 秀人 ? 偉民 永井 邦和 松山 健也 伊藤 吉保 柴田 良一

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.585, pp.894-899, 1995-05-25

被引用文献数

20 5

---

An influence of cooling rate on the fatigue reliability of aluminum alloy castings (AC4CH) was investigated. The results obtained were as follows : (1) As the cooling rate of AC4CH was increased, the porosities and the microstructure were controlled fine. (2) The fatigue strength of AC4CH produced through rapid cooling rate was superior to that produced through slow cooling rate, specially on the fatigue limit (N=10^7). (3) The effect of stress gradient on the fatigue limit is due to the probability that the maximum stress can put on the largest porosity in the specimen. (4) Micro porous defects were always observed at the origin of fatigue crack. Then, it could be interpreted that the fatigue life was related to the size of porous defect, based on fracture mechanics. (5) From the above relation and the statistical analysis on the size of porous defect, the fatigue limit of 99% remaining probability could be estimated.

著者

石田 和雄 小林 信之

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.50, no.453, pp.1042-1048, 1984-05-25

被引用文献数

2 1

---

An effective method for calculating the nonlinear-rocking response of ground-supported unanchored cylindrical tanks to earthquakes was developed. In this method, tank wall and liquid content are replaced with a mass-spring system, and the nonlinearity associated with the partial uplift of bottom plates due to overturning moments is considered as the rotational spring of bi-linear type which is determined by a static uplift analysis of tank bottom. The reliability of the dynamic analysis was illustrated by computing resonance frequencies, response accelerations and rotation angles of tank models and by comparing them with the results of vibration tests. A seismic deign procedure for nonlinear rocking of tanks is proposed, in which the uplift height of bottom plates is calculated by dynamic rocking analysis and the corresponding radial stress of them is obtained by static analysis. And a rocking analysis of a full-sized tank was tried, too.

著者

小林 信之 石田 和雄

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.50, no.451, pp.514-519, 1984-03-25

被引用文献数

1

---

When an earthquake hitting, the part of the bottom plate of the unanchored cylindrical tank will be lifted up from the foundation so that no resistance mechanism is existed against the uplift force caused by the overturning moment. The high stresses will be yielded in the bottom plate and the shell plate. This report concerns those problems. The calculation model was made in order to obtain the uplift resistance force, the uplift height, the reaction force from the foundation and the uplift region. In this model, the uplift region was considered as crescent shape, and the elasto-plastic, large deformation effect and the contact problem of the bottom plate was considered. From the comparison between this calculation model and the static tilt test of a thin bottom plate model tank, the calculation result was good agreement with the test.

著者

徳田 正孝 叶 萌 BUNDARA Borut SITTNER Petr

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.631, pp.491-497, 1999-03-25

参考文献数

45

被引用文献数

7 9

---

Quite unique and interesting behaviors of shape memory alloy under complex loading conditions, including the complicated path dependency, have been observed in systematic experiments by applying some combiened loads of axial force and torque to the thin-walled tubular specimen of Cu-based polycrystalline shape memory alloy. A set of constitutive equations is proposed, which can describe the complicated behaviors observed in the experiments. The mesoscopic approach is employed in the formulation because the complicated behaviors are closely related with the microstructural changes of materials, and the obtained equations show a reasonable coincidence with the exprimental results. In this first paper, the process of modelling and the detail of formulated constitutive equations are described, and the comparison between experimental resutls and computed results by using the proposed constitutive equations are shown in the second report.

著者

熊谷 一男

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.46, no.408, pp.894-900, 1980-08-25

被引用文献数

1

---

0. 02% C軟鋼線の, 降伏応力以下の応力を加えたひずみ時効において(1)応力は, 降伏応力の増加を最大10%促進する. (2)みかけの活性化エネルギは, 約1kcal/mol増加する. (3)応力による時効促進への寄与率は, ひずみ硬化が約20%, 新たに導入された転位への微細析出物の析出が約3%で, 促進の主たる要因は, 応力による侵入形固溶原子の拡散ならびに析出の促進と考えられることを示した.

著者

佐藤 千明 池上 皓三

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.58, no.554, pp.1913-1920, 1992-10-25

被引用文献数

2 2

---

The strength of adhesive shaft joints between carbon-fiber-reinforced plastics (CFRP) and stainless steel bonded with epoxy resin was investigated in room temperature and low temperature (-70°C) both analytically and experimentally. The distributions of stress for tensile load and thermal stress for cooling in the joint were analyzed by applying the elastic finite-element method. The strength of the joints was predicted by applying the strength law of CFRP, stainless steel, adhesive layer and their interfaces to the calculated stress distributions. The predicted strength was compared with the experimental strength of the joints. The effects of the overlapped length and diameter ratio on the joint strength were examined at both conditions of room and low temperatures. The joint strength for the initial failure is saturated by a certain overlapped length, but the strength decreases with increasing diameter ratio. The final joint strength in low temperature is larger than that in room temperature.

著者

西川 雅章 岡部 朋永 武田 展雄

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.75, no.751, pp.287-295, 2009-03-25

---

A numerical simulation was presented to discuss the microscopic damage and its influence on the strength and energy-absorbing capability of short-fiber reinforced plastic composites. The dominant damage includes matrix cracking and/or interfacial debonding, when the fibers are shorter than the critical length for fiber breakage. The simulation addressed the matrix cracking with a continuum damage mechanics model and the interfacial debonding with an embedded process zone (EPZ) model. The fictitious free-edge effects on the fracture modes were successfully eliminated with the periodiccell simulation. The advantage of our simulation was pointed out by demonstrating that the simulation with edge effects significantly overestimates the dissipative energy of the composites. We then investigated the effect of the material microstructure on the fracture modes in the composites. The simulated results clarified that the inter-fiber distance affects the breaking strain of the composites and the fiber orientation angle affects the positions of the damage initiation. These factors influence the strength and energy-absorbing capability of short fiber-reinforced composites.

著者

泉 聡志 横山 喬 寺岡 卓也 岩崎 篤 酒井 信介 斎藤 金次郎 名川 政人 野田 秀樹

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.71, no.703, pp.380-386, 2005-03-25

被引用文献数

8 16

---

We have developed a new nut named 'super slit nut (SSN)', which realizes anti-loosening performance without complicated tightening procedures. In this study, tightening behavior and loosening behavior caused by shear load are analyzed by mean of three-dimensional finite element method. It is found that SSN has a prevailing torque of 15 to 19Nm, which closely agrees with experimental data. The load distribution of thread depends on the rotation angle of nut. At the angle of 24.6 degree, the distribution of 1st pitch turns to be 10% larger than that of conventional nut, reflecting the decrease in the thread at slit region. It is also found that the anti-loosening performance cas be realized by the thread contact force at the slit region. Since its contact force does not depend on the tightening force, the effect of anti-loosening performance drastically increases as the tightening force is decreased. Shear fracture would initiate not at slit region but at the bottom of 1st thread, whose stress is about 10% larger, as compared with conventional nut. Moreover, by mean of tensile and fatigue experiments, it is concluded that SSN involves sufficient strength in practical use.

著者

中西 康彦 中桐 滋

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.60, no.577, pp.2157-2162, 1994-09-25

被引用文献数

3

---

This paper deals with topological optimization of elastic frames by means of the boundary cycle used in the algebraic topology and genetic algorithm. The optimum frame is so defined in this study that the deformation of an interesting point of the frame is minimal for a given limit of weight, and that any members with a tip not connected to other members, except loading points, are eliminated. The optimum topology is searched efficiently through the boundary cycle which yields the one-dimensional simplicial complex without any tip, satisfying the topological condition of no idle tip present. The boundary cycle is derived from the chain and boundary homomorphism which plays an important role of decoding of the genotype into the phenotype in the genetic algorithm, and is included in the string used in the genetic algorithm for the representation of frame topology. The numerical examples are concerned with minimization of the deformation of two-dimensional frames subject to bending, and three-dimensional frames subject to torsion or expansion.

著者

竹内 洋一郎 石田 良平 辻 正利

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.430, pp.747-757, 1982-06-28

被引用文献数

2

---

有限円柱の一つの端面に偏心円形熱源のある問題は,平面熱応力問題として解決できない厚肉円板の,一方の平たん部の境界面に偏心円形熱源の問題ともなり,工業上有用性が多い.この問題は完全ないわゆる三次元熱応力問題による解析によらねばならない.本研究は熱弾性変位ポテンシャル,ミッチェルおよびブシネの関数の三者に関する熱弾性基礎方程式を解いて,非定常熱応力分布を求めた.

著者

神宮 利夫 永倉 和郎

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.544, pp.3069-3076, 1991-12-25

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A robotic manipulator is simplified by numerous beams with pinjoints between them and an anchor pinjoint at the base. The beams under impact loading are allowed to rotate about the axis of the pinjoint. The dynamic response of a vertical chain for a transverse load suddenly applied along every beam is theoretically analysed. The angular and linear acceleration of the mass center of beams, reaction force at the pinjoints, shearing force and bending moment along the beams is presented as a function of impact load. As the vertical chain consisting of one plaster beam and one steel beam, or two with a pinjoint between them, is subjected to the collision of the flier steel rod accelerated by the air gun, the location of the fracture of the plaster beam is measured experimentally. The validation of the theory is confirmed by comparison of the location of the critical bending moment with the position of the fracture of the beam.

著者

趙 希禄 胡 亜波 萩原 一郎

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.76, no.769, pp.1131-1138, 2010-09-25

参考文献数

8

被引用文献数

1

---

As regard to car frontal crash, previous researches have indicated that the front side member plays a major role in energy absorption. For protecting the passengers, the front side member is expected to absorb crash energy as much as possible. In this study, we investigated the crash characteristics of half cut type side member structure by optimal design method to improve energy absorption ability. We developed an automatic optimal design system, in which the analysis meshes are generated with a group of design parameters and shape optimization is carried out automatically, The design variables are side member cross section shape, spot welding pitch length, divisional section numbers and radius difference along the axial direction, and the number of subdivision levels. As the result, the optimal side member structure with half cut type is capable of absorbing 1.44 times (1.29 times per unit mass) more energy than the original rectangular cross sectional side member structure with half cut type which is generally used.

著者

幡中 憲治 藤満 達朗 安藤 隆之 橘 輝夫 中居 嘉一郎

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.55, no.512, pp.773-781, 1989-04-25

被引用文献数

1

---

The test system was newly developed for evaluating precisely the strength of ceramics at elevated temperatures, being equipped with the laser beam-type displacement measuring system. Four-point bending tests were performed on the silicon-nitride ceramics at elevated temperatures from 800℃ to 1300℃. The linear relationship held between the load, P and the displacement, 6 at test temperatures below 1200℃. The P vs. δ plot, however, deviated from the linear relationship at temperatures above 1200℃, suggesting the occurrence of plastic deformation. The flexural strength remained unchanged in the test temperature range from room temperature to about 900℃, and then this decreased gradually with further increase in the test temperature. The fracture toughness measured by using the Chevron notch-type specimen was nearly constant in the temperature range from room temperature to about 1100℃. The fracture toughness obtained from the Knoop-indented specimen was discussed in comparison with that from the Chevron notch-type specimen.

著者

結城 良治 北川 英夫 東郷 敬一郎

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.47, no.422, pp.981-989, 1981-10-25

被引用文献数

2

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本報は, 従来のデータの得られていなかった二軸荷重重下の疲労き裂成長の低ΔK_I 領域特性と下限界条件ΔK_<Ith> を高張力鋼きつき系統的に調べ, またこの疲労き裂の開閉挙動を調べたものである. その結果, 二軸荷重下のき裂成長特性は, 単軸荷重下の場合と同様にΔK_Iと応力比 R_K(=K_<I min>/K_<I max>) あるいはΔK_<Ieff> で統一的に特性づけられることを明らかにした. 本実験では, き裂に平行な応力(非特異定数項)の影響は認められなかった.

著者

大村 悦二 小川 健輔 熊谷 正芳 中野 誠 福満 憲志 森田 英毅

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.764, pp.446-448, 2010-04-25

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In stealth dicing (SD), a permeable nanosecond laser is focused inside a silicon wafer and scanned horizontally. A thermal shock wave is propagated every pulse toward the side to which the laser is irradiated, then a high dislocation density layer is formed inside a wafer after the thermal shock wave propagation. In our previous study, it was supposed that an internal crack whose initiation is a dislocation is propagated when the thermal shock wave by the next pulse over-laps with this layer partially. In this study, a two-dimensional thermal elasticity analysis based on the fracture mechanics was conducted. The internal crack propagation was analyzed by calculating the stress intensity factor at the crack tips and comparing with a threshold of that. As a result, validity of the previous hypothesis was suggested.

著者

多田 幸生 長嶋 達也 高田 昌紀

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.58, no.551, pp.1115-1121, 1992-07-25

被引用文献数

2

---

The brain consists of brain tissue, blood and extracellular fluid. We can thus consider that brain tissue has multi-phasic properties. There is a very important interrelation between the tissue and the fluid. Thus, we consider that the respective factors on brain neurosurgery, the distribution of brain tissue pressure and extracellular fluid flow are very important, and we cannot neglect those factors closely related to metabolism of the brain tissue. This study constructs a two-dimensional consolidation model of the brain using the finite element method (FEM) and simulates the flow and distribution of cerebrospinal fluid (CSF). The two dominant equations on the consolidation theory are approximated numerically in time by the finite difference method and in space by the FEM. The results obtained by computer simulation regarding brain edema using the FEM are compared with the pathological observation with regrad to the flux distribution and flow direction of CSF, and we conclude that they are much the same as those from the view point of the pathological and clinical surgery. We furthermore propose that we should take the boundary conditions of pressure of the subarchanoid space and ventricle into consideration in the simulation of brain edema.

著者

都井 裕 諸正 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.557, pp.240-247, 1993-01-25

被引用文献数

7 3

---

Fracture behaviors of brittle polycrystalline solids such as ceramic materials are deeply related to microcracking. Continuum damage mechanics is considered a powerful theoretical framework to deal with brittle microcracking materials, however, it is fairly difficult to obtain analytically as well as experimentally evolution equations for microcracking and reduced elastic compliances of microcracked solids. In the present study, a mesoscopic (grain level) simulation method using a discontiuum mechanics model is proposed to solve these problems. The validity and limitations of the isotropic theory of continuum damage mechanics are studied in the first report.

著者

金崎 俊彦 楢崎 千尋 峯 洋二 松岡 三郎 村上 敬宜

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.1717-1724, 2006-11-25

被引用文献数

11 17

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The effect of hydrogen on fatigue crack growth behavior of four stainless steels has been investigated from the viewpoint of martensitic transformation. The crack growth rates in hydrogen-charged SUS304 and SUS316 were accelerated. The crack growth rate in hydrogen-charged SUS316L was slightly higher than uncharged SUS316L. However, the crack growth rate in SUS405 hardly changed in comparison with uncharged specimens. The matensitic transformation on fatigue fracture surface was detected by X-ray diffraction both in hydrogen-charged and uncharged specimens of SUS304, SUS316 and even in SUS316L. However, the fracture surface of SUS316L, in which the crack growth rate was increased slightly by hydrogen, showed less martensitic transformation than that of SUS304 or SUS316. It is presumed that martensitic transformation in the vicinty of fatigue crack tip contributed to the effect of hydrogen on crack growth rate. Fatigue tests of SUS304 and SUS316L, which were pre-strained at -70℃ to enhance a martensitic transformation, were carried out to study the influence of hydrogen and martensite on crack growth. Crack growth rate was remakably increased by hydroggen in not only pre-strained SUS304 but also in pre-strained SUS316L. The hydrogen content of pre-strained hydrogen-charged specimen was much higher than unstrained hydrogen-charged specimens due to the increase in martensite through which hydrogen diffuses much easier and faster than through austenite. The slip bands around crack tip in the hydrogen-charged specimens were less and more discrete than that in the uncharged specimens.

著者

小林 孝 小林 繁夫 紀平 正知

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.46, no.402, pp.197-204, 1980-02-25

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頭がい骨を円筒形容器として中にほとんど非圧縮の柔らかい弾性体を詰めた頭がい模型を用いて, 有限要素法により頭がい衝撃問題の基礎的研究を行った. 脳はせん断弾性係数が体積弾性係数にくらべて非常に小さく従ってポアソン比が0. 5に近い材料なので, 普通の変位法では誤った結果を与える. この困難を克服するため Herrmann の変分原理を用いた. 内部弾性体の圧力応答に対してその体積弾性率と端板の変形の影響が大きいことを明らかにした.