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

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.

著者

皮籠石 紀雄 西谷 弘信 後藤 真宏 豊廣 利信 北山 智

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.57-61, 1993-01-25

被引用文献数

2 2

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Statistical analysis is necessary in evaluating the fatigue life of structures. In the present study, rotating bending fatigue tests were carried out on specimens with two small blind holes of a 5052 A1 alloy in order to investigate the distribution characteristics of the fatigue crack growth life based on the small-crack growth law dl/dN= C_1σ^n_al. The crack growth rate in each specimen was determined uniquely by σ^n_al, therefore the crack growth life can be predicted by the small-crack growth law. On the assumption that the value of n is a fixed one and the value of C_1 is a random variable, the distribution of the crack growth rate can be evaluated through the value of C_3 in the relationship dl/dN=C_3l. C_3 follows a Weibull distribution approximately. The calculated distribution of the ocracy growth life based on the small-crack growth law and the distribution of C_3 was in good agreement with the experimental results.

著者

米山 聡 後藤 仁一郎 隆 雅久

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.620, pp.1007-1013, 1998-04-26

被引用文献数

3

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The authors propose a new method for simultaneous determination of both fringe order and principal direction of birefringence in practical photoviscoelastic analysis using a white incident light with a set of the three primary colors. When using this method, not only fringe order but principal birefringence direction are successfully and easily determined from a single color image through a plane polariscope. Utilizing this method together with photoviscoelastic constitutive equations, timedependent principal stress and strain difference, also their directions are obtained. In this paper, the fundamental of the tricolor photoviscoelastic technique is described briefly, then a successful application of the method to the analysis of an example of viscoelastic problem is shown.

著者

柏村 孝義 森 孝男 白鳥 正樹 于 強 丸山 修

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.603, pp.2422-2427, 1996-11-25

被引用文献数

14 2

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The authors proposed a new practical optimum design method (=statistical optimization method) that consists of two steps of an effectivity analysis (using a combination of the design of experiments and the structural analysis) and mathematical programming. The design of experiments is used to generate the approximate evaluation functions for the controlling behavior depending on the changes of design variables of the object structure, using finite element analysis (FEA). The evaluation functions can also be used as tools for directly estimating the behavior of the designed structure. 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 call be used in solving various problems. In this study, the authors applied the present method to the optimum design of a frame column subjected to axial crushing. This study deals with many complex behaviors such as large deformation, contact and material nonlinearities as well as impact behavior. However, this problem has been solved easily using the present method, and satisfactory results of the effectivity analysis and optimum design are obtained.統計的最適化手法を用いて,複雑な非線形現象である動的圧潰現象における最適化および影響度解析を行った.応答曲面を用いた本手法では,複雑な非線形挙動を再現する高精度な推定式を得ることができるとともに最適化計算においても高い精度を有することが確認できた.

著者

米倉 清治 北須賀 健志 西野 創一郎 鈴木 秀人

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.623, pp.1929-1935, 1998-07-25

被引用文献数

1

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The effect of the mesostructure of Si_3N_4 particulates and PAI resin film on the wear of the film surface due to sliding motion of paper were experimentally examined in respect to the self-lubrication. And wear process of this hybrid resin film was simulated visually on the computer. We tried to examine wear mechanism by means of the visual simulation. The results were as follows. (1) Wear amount of mesostructural resin film due to the sliding of paper has been reduced approximately to one tenth as compared with conventional epoxy plastic film. (2) Rolling and sliding trace of Si_3N_4 has been observed over the film surface in the sliding direction of paper after sliding the paper. The trace that was found in this instance can be called as Meteoric Track. (3) We closely looked at the particle movement, made a simple model, and simulated visually. By this simulation, we could observed the particle behavior and meteoric track behavior of wear process which is not possible at actual experiment. (4) The change of wear volume in the simulation almost agreed with that of experiment. So, this simulation was suitable, and can analyze the Meteoric Wear. And, we propose the new evaluation expression of Meteoric Wear by modifying Rabinowicz's abrasive wear model.

著者

矢川 元基 渡辺 隆之 石渡 俊

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.401, pp.87-96, 1980-01-25

被引用文献数

1 1

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本論文では, EPAS プログラムの開発と応用について論じたものである. 有限要素法による三次元連続体の非弾性解析は, 極めて多くの計算時間を要するため実用性の点で問題があった. 著者らは, 三次元構造の局部的な非弾性挙動の解析を効率よく行うためラグランジュ乗数法に基づく結合要素を EPAS プログラムに導入し, 計算時間と容量の短縮化を行った. この結合要素は, プログラム内で通常の要素と同様に取扱うことができる.

著者

孫 智剛 牧野内 昭武 矢部 比呂夫

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.69, no.688, pp.1775-1781, 2003-12-25

被引用文献数

2 1

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The effectiveness of the scleral buckling operation, which is one of those most frequently applied to clinical treatment of the rhegmatogenous retinal detachment in the eyeball, strongly depends on the surgeon's experience so that it is usually difficult to achieve a fully satisfactory effect. Aiming at computer-aided operation planning employing the FEM simulation technique, a 2-D FEM program for a coupling analysis of the hyperelastic solid and static liquid has been developed to qualitatively simulate the procedure of this kind of operation. In this paper, a 3-D FEM program that provides all the functions required for simulating the complicated 3-D procedure of the buckling operation, such as solid-liquid coupling analysis, contact treatment between deformed soft tissues and analyses of buckling and suturing process, is developed. An improved algorithm of the coupling analysis which can avoid the time and memory consuming problem existing in that used in the 2-D one as well as an effective approach in treating the contact between deformed soft tissues are employed in this program. After validating its analysis accuracy through a testing analysis, a simulation of the encircling buckling operation procedure is presented, and the results demonstrate the ability of the program to predict the most suitable factors for an effective clinical operation.

著者

久保 司郎 大中 幸三郎 大路 清嗣

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.575, pp.1638-1643, 1994-07-25

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The present authors proposed the adjoint boundary integral method for identifying heat source or force in a domain from values of boundary integrals involving an adjoint operator. The integrals can be evaluated if boundary values are available over the entire boundary of the domain. In the present study a Poisson field source is identified from noisy and discrete boundary observations by applying the method. Adaptive Gauss quadrature enables evaluation of the boundary integrals from observations at discrete points, which deviate from the Gauss points for approximate evaluation of boundary integrals. Numerical simulations are carried out for identifying location and intensity of a concentrated source in a two-dimensional domain. Effects of errors in boundary observations, deviation of locations of observation points from the Gauss points, the order of Gauss quadrature, and the location of source on the accuracy of the identification are discussed. It is shown that the location and intensity of the source can be estimated reasonably from noisy and discrete observations by applying the adjoint boundary integral method with the adaptive Gauss quadrature.

著者

箕浦 潔 荻 博次 平尾 雅彦

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.62, no.603, pp.2520-2526, 1996-11-25

被引用文献数

2

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In this paper, we present a technique to generate axial shear acoustic resonance in a cylindrical rod or pipe by a magnetostrictively-coupled electromagnetic acoustic transducer (EMAT). We apply this ultrasonic technique to monitor rotating bending fatigue damage. The technique is based on the electromagnetic acoustic resonance (EMAR), which is a combination of the resonant technique and a noncontacting EMAT. The EMAT for the axial shear wave consists of a solenoidal coil to apply a static field along the sample rod (or pipe) and a meanderline coil to induce the dynamic field, relying on the magnetostrictive effect in ferromagnetic metals. The axial shear wave propagates along the circumference of the cylindrical rod or pipe with axial polarization. The resonant mode is determined by the sample dimensions and the wavelength. The major advantage is the capability of evaluating the inhomogeneous materials character in the radial direction using the different resonant modes. The attenuations and the resonant frequencies of the first three resonant modes are measured during the rotating fatigue test. The attenuation shows a remarkable sensitivity to damage accumulation, mainly due to the evolution of the dislocations and the grain size. The ultrasonic evaluation is interpreted in terms of the photomicrograph and transmission electron micrograph observations.

著者

井上 達雄

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.68, no.674, pp.1427-1429, 2002-10-25

著者

井上 裕嗣 上林 稔 岸本 喜久雄 渋谷 寿一 小泉 尭

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.542, pp.2523-2528, 1991-10-25

被引用文献数

2 1

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The Laplace transformation is known as one of the most powerful mathematical techniques for solving wide range of problems in engineering. For its application to practical problems, many authors have extensively studied methods of numerical inversion. On the other hand, the method of numerical transformation has not been studied very much. For this reason, most of the applications were limited to theoretical or numerical analysis and there were few applications to experimental analysis. To overcome this problem, both of the numerical transformation and inversion are studied in this paper. Numerical accuracy is evaluated and discussed using two test functions, sinusoidal and step function. A chart is presented for determining the parameters of computation under a specified accuracy.