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

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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

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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

仙波 浩雅 岡部 永年 山地 徹 沖田 圭介 山内 清 松本 賢哉

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.71, no.709, pp.1234-1242, 2005

被引用文献数

1

---

This paper deals with the bulge process for forming the single-stage bellows of TiNi shape memory alloys, which is proposed as a new type of seismic applications, and especially considering the material's special behavior. Thin walled tubes with 20% cold work, whose composition is Ti51.0 at% Ni, were prepared. First they are appropriately heat-treated and then the rubber bulge process is introduced for the tubes under the condition of austenite phase at room temperature. Displacement control method is adapted to the process. Theoretical prediction of change in outer diameter of the tube on compression is derived, and modified taking into account the progress of the stress-induced martensite transformation on tube's surface by observing the detachment of the oxide layer of the surface. Finally theoretical relationship between compressive displacement and the outer diameter of the tube, which is the most inportant for the design of the bellows shape, is cleared.

著者

川節 望 新藤 健太郎 田北 勝彦 増山 不二光

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

巻号頁・発行日

vol.74, no.741, pp.669-677, 2008-05-25

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Glass Fiber Reinforced Plastics (GFRP) have been applied to products such as building components and various structural materials in industrial plants due to their excellent lightness and corrosion resistance, as well as weather resistance since the 1980's. Use of GFRP for large-scaled components and/or components with repetitive load has increasingly widespread in recent years, and both tensile and compressive properties have thus become important. Reinforcing laminate for GFRP has been mainly woven fabric such as glass woven roving due to its easy handling. However, its fiber winding and gap occurrence have been problems to be solved. In the recent years, new fiber fabrics for reinforcement have come on the market owing to rapid development of weaving machine, and one of the new fabrics is the stitched fabric. This glass fiber stitched fabric has been increasingly developed in Europe and all over the world for over ten years, and in Japan, has extended its application for ship for about ten years. This study investigates and examines GFRP reinforced with unidirectional glass fiber stitched fabric, in respects of the effect of fiber laminated constitution, fiber content and fiber diameter on tensile and compressive properties. Additionally, this study also examines relevance between weaving patter of fiber and strength property by comparing 0 degree/ 90 degree stitched fabric with GFRP with general woven roving.

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

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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

徐 章 池田 郁雄

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.117-123, 1993

被引用文献数

1

---

The destructive phenomenon of brittle and fatigue fracture is becoming extremely important in the problem of structures' safety. In this paper, to elucidate the fracture mechanism, it is tested experimentally to explicate the destructive phenomenon of the fractured section and fissure progression occurring due to thermal shock in typical brittle glass materials. Specifically, by the application of the newly developed method of applying electric resistance-vacuum evaporated thin films, it became possible to accurately measure the velocity of fissure propagation and also each block of glass and ceramics. As a result, the maximum velocity of fissure propagation for the glass was approximately 1 500-1 700 m/s and its average velocity was 650 m/s. It is also found that the velocity of fissure propagation in the glass by thermal shock under the condition of adding load by four-points bending is almost approximatrely 3 000 m/s.

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.

著者

阿部 博之 後藤 智 木村 光男 櫛引 英嗣 荒井 茂

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.578, pp.2452-2458, 1994-10-25

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At the present time, there is no adequate method for experimental measurement of wall stresses in the intact ventricle. Thus, many mechanical models to predict such stresses have been proposed, in which the residual stress was ignored so that the circumferential stress at the endocardium of the left ventricle was extremely large compared with that at the epicardium. The work expressed, such as oxygen consumption, is supposed to be almost uniform through the wall thickness, or to be somewhat larger at the endocardium than at the epicardium. The models may be improved by taking account of residual stress. To take residual stress into account in mechanical models, one must measure residual strains in the no-load state of the left ventricle. The residual strains were calculated by using sliced canine left ventricles obtained during isovolumic contraction. The residual strains determined from the experiment were applied to the model proposed in the present paper and the distributions of the wall stresses were obtained. As a result, the stress concentration at the endocardium of the left ventricle was found to be largely reduced.

著者

和田 均 安藤 善司 西村 融

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.52, no.482, pp.2416-2421, 1986-10-25

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A simple procedure for obtaining a stress intensity factor using FEM proposed by the authors was applied to analyze the problem of a lug with cracks. First, to confirm its usefulness for the present method, a problem for a rectangular plate with an edge crack subjected to three point bending was calculated by the present method. The present results were compared with present photoelastic experimental results or usual results. Next, a dynamic calculation for the same problem and a problem for a lug with cracks were carried out by the present method, and the results were compared with the present experimental results using a strain gaga method. Consequently, as the usefulness of the present method was recognized, the static and the dynamic stress intensity factor of the lug with cracks was investigated by the present method varying a pin hole diameter or a crack length systematically. Furthermore, the relation between the static stress intensity factor and the dynamic one was presented.

著者

立石 哲也 白崎 芳夫 島村 昭治 勝世 敬一

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.45, no.396, pp.823-835, 1979-08-25

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合目的な海綿骨の構造と特性を材料工学的に応用することを目的とするソフトメカニクス研究の第一歩として,粘性流体を充てんした多孔質粘弾性体の力学モデルを提案し,これを用いて水,関節液,タービン油,バクトラ油などの粘性流体を含浸した多孔質ポリプロピレンの衝撃吸収性と過重支持性を理論的に明らかにすると共に将来の軟機械用材料に欠くことのできない機能的な可変モジュラス材料の設計の指針を与えた.

著者

落合 芳博 小林 正

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.628, pp.2914-2919, 1998-12-25

被引用文献数

3

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Elastoplastic problems can be easily solved by the boundary element method. However, even if BEM is used, domain integrals are necessary for elastoplastic problems. The conventional multiplereciprocity boundary element method cannot solve the elastoplastic problem, because the distribution of initial stress or initial strain cannot be given analytically. This paper shows that the elastoplastic problem can be solved without the domain integral by the improved multiple-reciprocity boundary element method. In this method, the distribution of initial stress is interpolated using a boundary integral equation. A new computer program was developed and applied to several elastoplastic problems.

著者

大路 清嗣 辻 昌宏 久保 司郎 小野 嘉雄 八幡 篤 梅井 健司

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.59, no.562, pp.1429-1436, 1993-06-25

被引用文献数

7 11

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A criterion was sought for predicting the path of a fatigue crack in HT80 steel propagating in residual stress fields. The problem was investigated with respect to two questions : (I) which was the dominant factor in determining the fatigue crack path, the cyclic components or the maximum values of stress intensity factors (SIFs), and (II) what kind of criteria, expressed in terms of the foregoing dominant SIF parameter, could be used for predicting the fatigue crack path ? For the first question, it was indicated that the cyclic components of SIFs determined the crack path. For the second question, it was found that the crack path could be predicted by applying the Δσ_θ maximum criterion, which predicted that the crack propagated in the direction of the maximum range of circumferential stress component. Crack propagation lives for cracks curved due to the existence of a hole were calculated by applying the "U- (crack opening ratio) estimation" method based on the superposition principle proposed by the present authors. The predicted lives were in good agreement with the experimental results.

著者

三好 俊郎 白鳥 正樹

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.48, no.433, pp.1136-1141, 1982-09-25

被引用文献数

2 1

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3点曲げおよび中央き裂を持つ試験片の有限要素解析を行い,全面降伏荷重およびJ積分の平面ひずみ状態と平面応力状態での比が塑性拘束率βに等しいことを示した.ついですべり線場解析に基づき,3点曲げ,CT,中央き裂および両外側き裂の引張りに対して有限要素解析と同じ結果が導かれることを示した.最後に表面は平面応力,内部は平面ひずみからなる三次元積層板モデルを提案し,J積分評価の際の板厚効果について考察した.

著者

澤 芳昭 豊田 兼昭 池内 和雄 片寄 益巳

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.567, pp.2575-2580, 1993-11-25

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In turbine design, because the joint between the turbine blade and the rotor bears the largest stress, it is important to study the stress at this position. The fir-tree type is one of the most efficient joint configurations for blade fastenings. Many papers have reported on the fir- tree turbine blade, but these mostly dealt with experiments using two-dimensional analysis. We therefore experimented with three-dimensional stress analysis in frozen photoelasticity. In this examination, the study was made of characteristic occurrences under centrifugal force produced by rotation simulating an actual turbine. The analysis of the fir-tree joint was performed for two tests. One was for straight entry and the other was for curved entry. Photographs were obtained for the photoelastic fringe, stress distribution, and stress concentration factors. The results were as follows radially, in both the straight and curved entry types, the highest stress concentration occurred at the tip serration. Axially, in the curved entry type, the highest stress concentration point was the axial center, and in the straight entry type, the distribution was uniform.

著者

村上 敬宜 堤 一也 藤嶋 正博

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.62, no.597, pp.1124-1131, 1996-05-25

被引用文献数

15 19

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In order to investigate the effect of surface roughness on the fatigue strength, fatigue tests for maraging steel which was subjected to aging treatment and was free of residual stress, were carried out. As an artificial surface roughness, extremely shallow periodical notches with notch radii P=0 and 200μm, and notch depths a=12, 22, 40 and 65μm were introduced. In addition to the effect of surface roughness, the effect of nonmetallic inclusions was also considered. The equivalent defect size (√(area<SUB>R</SUB>)) which controls the fatigue limit of specimen containing the surface roughness is defined by the function of depth and Pitch of the roughness. The lower bound of the fatigue limit for various levels of roughness can be predicted by substituting the equivalent maximum defect size (√(area<SUB>m</SUB>axt)) to the √(area) parameter model. The value of √(area<SUB>m</SUB>axt) can be evaluated by considering the interaction effect between the maximum inclusion size and roughness. The predicted values were examined by experiments and it is shown that the method of prediction is available for practical applications.

著者

沢 俊行 天摩 勝洋 西ヶ谷 達 仲野 雄一

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.59, no.563, pp.1763-1770, 1993-07-25

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The stress of band adhesive butt joints in which the interfaces are partially bonded, was analyzed using a two-dimensional, theory of elasticity in order to establish fracture criteria for the case in which the joints of dissimilar adherends are subjected to tensile loads. In the analysis, when the interfaces are bonded by an adhesive at two regions, the dissimilar adherends and the adhesive are replaced with finite strips. In the numerical calculations, the effects of the ratio of Young's modulus of adherends to that of adhesives, the thickness of the adhesives, the bonding area and position and load distributions on the stress distributions at the interfaces were demonstrated. In addition, with use of the stress distribution, a method for evaluating joint strength was proposed. As a result, it was observed that band adhesive joints were available when the bonding area and positions were varied taking into account external load distribution. For verification, experiments were performed on the strain of adherends and the joint strength. Analytical results were consistent with the experimental ones.