著者

北村 郁生 前田 将輝 田中 博人 劉 浩

出版者

一般社団法人 日本機械学会

雑誌

年次大会 2013 (ISSN:24242667)

巻号頁・発行日

pp._J027041-1-_J027041-5, 2013-09-08 (Released:2017-06-19)

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Hummingbirds are the only species in birds capable of performing continuous hovering flight. However, the precise aerodynamic force generating mechanisms, which should be associated with the dynamic wing-morphing, still remains unclear. In this study, targeting at hummingbird Amazilia amazilia, we aim at conducting a systematic analysis of flapping-wing kinematics and dynamic configuration of the wings during hovering flight. With use of a filming system consisting of four synchronized digital high-speed video cameras operating at 2000 frames per second, we recorded a sequence of hovering with sufficiently high resolution. With the video images, characteristic points on the right wing of the hummingbird were tracked. Additionally, we conducted the flapping experiment to evaluate the effect of the wing-morphing on lift generation. Two time-variant wing deformation parameters were obtained: wing surface area and spanwise twist. We found that the wing area shows a variation up to 20% within a wingbeat cycle. Our results indicate that the time variation of the angles between adjacent primary feather shafts is the main cause of the variation of the wing area. The wing twist shows asymmetric variation during upstroke and downstroke, and this asymmetry is prominent for the inboard part of the wing. The hummingbird-inspired flapper experiment shows it is generating sufficient aerodynamic force to support the original hummingbirds weight based on which it is modeled.

著者

大河内 信夫 板倉 嘉哉 堤 一郎 白井 靖幸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会関東支部総会講演会講演論文集 2007.13 (ISSN:24242691)

巻号頁・発行日

pp.171-172, 2007-03-15 (Released:2017-06-19)

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The authors studied Fujiwara's water-wheels for irrigation which were built at Kazusa region in Chiba prefecture. They surveyed literature on bucket chain conveyor system for water in the Edo period. There were 3 materials concerned with Fujiwara's water-wheel. The authors restored Fujiwara's water-wheel bucket which was drawn on the Report of Archaeological Investigation carried out the Fujiwara-Type scoop wheel, No. 1 and 2 in Yoro, Ichihara city, Chiba prefecture. They compared data of Fujiwara's water-wheel bucket restored with data of literature for Fujiwara's water-wheel. Fujiwara's water-wheel power was calculated from data of the bucket restored.

著者

森 悠貴 橋本 和宗 井上 博夏

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 (ISSN:21879761)

巻号頁・発行日

pp.23-00011, (Released:2023-11-20)

参考文献数

11

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This paper proposes a novel path planning algorithm designed for efficient lunar water exploration. The proposed algorithm leverages a Bayesian network-based sensor model in combination with the RRT* algorithm. It is well-known that water is highly likely to be present in permanently shadowed regions (PSRs). However, during exploration within these regions, the rover must escape to illuminated areas within a limited time to recharge its battery. Therefore, it is crucial to develop a path planning algorithm that ensures both timely battery recharging and efficient water exploration. To address this challenge, we first introduce a sensor model based on a Bayesian network for the neutron spectrometer. Subsequently, we propose an algorithm that utilizes this sensor model and the RRT* algorithm to effectively explore water on the lunar surface. The paper provides a numerical simulation, using real data about time-variant illumination areas and time-invariant PSRs on the lunar surface, to illustrate the effectiveness of the proposed algorithm. The results reveal that the algorithm accurately and efficiently detects water under realistic illumination conditions.

著者

石井 啓範 冨田 邦嗣

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2006 (ISSN:24243124)

巻号頁・発行日

pp._2A1-B07_1-_2A1-B07_2, 2006 (Released:2017-06-19)

被引用文献数

1 1

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A lot of work machines based on hydraulic excavators were developed for various complex work fields like dismantlement, industrial waste disposal, etc. And such kinds of work machines also play important parts in disaster recovery such as earthquakes, typhoon, and flood. We think that an adaptation to more complex works will be requested in the future. To achieve more complex handling work function, we developed a new type of work machine called "ASTACO". ASTACO features at including two fronts and is based on 7-ton class hydraulic excavator. A new operation system can let the operator to handle the two fronts with his two hands freely and intuitively at the same time. In this paper we report summery and key function of ASTACO.

著者

坂倉 圭 山本 悟

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.71, no.709, pp.2213-2217, 2005-09-25 (Released:2011-03-03)

参考文献数

12

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The preconditioned flux-splitting method developed by our group is applied to the computation of two-dimensional natural convections. This method is based on the Roe's flux-difference splitting, the LU-SGS scheme, and the preconditioning method. In the present study, the natural convection in a cavity at Ra=103-106 were calculated by the present method, and the numerical results are compared with the benchmark results already reported by Davis, Okanaga and Chenoweth. Finally, the reliability and the limitation of the present preconditioning method applied to the convection problems are discussed in detail.

著者

小浦方 格 守山 光三 原 利昭

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.68, no.665, pp.101-108, 2002-01-25 (Released:2008-02-26)

参考文献数

16

被引用文献数

2

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It is important for senior brass instrument players to study the detailed control parameters for embouchure building. While many investigators have reported the preliminary data on the muscle behavior, the precise aspects are unrevealed so far. The purpose of the present paper is to study dynamic perioral muscle behavior of French horn players and to investigate their lip valve function by measuring the contact pressure on teeth buccal surface during playing. It was shown from the experimental results that the advanced players contracted depressor and levator angulioris especially for high tone playing. The combined contraction by these muscles may contribute to smaller lip aperture formation appropriate for higher tones. Inversely a strong contraction of m. buccinator was found insignificantly from the results for the advanced players while it is well known that m. buccinator contracts hard during playing.

著者

山田 和豊 喜久田 啓明 古川 雅人 郡司嶋 智 原 靖典

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B編 (ISSN:18848346)

巻号頁・発行日

vol.79, no.801, pp.900-916, 2013 (Released:2013-05-25)

参考文献数

28

被引用文献数

1 1

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Flow fields near rotating stall inception in a low-speed axial compressor rotor with two different tip clearances have been investigated by instantaneous measurements of casing wall pressure distributions using 30 high response pressure transducers and by detached eddy simulations (DES) using 120 million grid points. It is found that the stall inception process in the large tip clearance case is dominated by the breakdown of the rotor tip leakage vortex, in contrast to the spike-type stall inception in the small tip clearance case which is dominated by the leading-edge separation near the rotor tip. The vortex breakdown induces the large oscillation of the tip leakage vortex with its unsteady nature, resulting in the low-pressure regions in the instantaneous casing wall pressure field and the high pressure fluctuation region on the pressure side of the adjacent blade tip in the ensemble-averaged casing wall pressure field. The large blockage effect due to the tip leakage vortex breakdown causes the rotating disturbance propagating in the circumferential direction, which can appear and disappear with a slight change in the flow rate.

著者

井戸 理恵子

出版者

一般社団法人 日本機械学会

雑誌

シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集 2011 (ISSN:24329509)

巻号頁・発行日

pp.510-511, 2011-10-30 (Released:2017-06-19)

著者

前野 隆司 小林 一三 山崎 信寿

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.63, no.607, pp.881-888, 1997-03-25 (Released:2008-02-26)

参考文献数

14

被引用文献数

29 27

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There are several tactile receptors at specific locations in the tissue of human fingers. In this study we calculate in detail the deformation of finger tissue when a finger comes into contact with a rigid plate using a FE (finite element) model in order to clarify the reason for the precise location of the receptors. The FE model is constructed using the measured geometry and properties. As a result, we found that the strain energy is concentrated at tactile receptor locations. When a frictional force is applied, the stress/strain is concentrated near the edge of the contact area. By calculating using models with/without epidermal ridges/papillae, we found that the shape of the epidermal ridges/papillae influences the stress/strain distribution near the tactile receptors.

著者

須藤 浩三 高見 敏弘 矢野 賢司

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 B編 (ISSN:03875016)

巻号頁・発行日

vol.58, no.548, pp.1015-1021, 1992-04-25 (Released:2008-03-28)

参考文献数

10

被引用文献数

7 4

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An experimental study has been carried out for the turbulnt flow through a circular-sectioned 90°bend of a curvature radius ratio of 4.0 with inlet and outlet straight pipes attached. Three components of mean and fluctuating velocities were measured by the technique of rotating a probe with an inclined hot wire under a Reynolds number of 60000. The flow patterns of main and secondary streams, and Reynolds stress distributions in pipe sections are illustrated with figures, and explanations are added on the process of phenomena in the streamwise direction.

著者

佐々木 浩一

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.57, no.539, pp.2211-2216, 1991-07-25 (Released:2008-02-21)

参考文献数

6

被引用文献数

2 1

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To upgrade the riding comfort of the 0 Series Tokaido-Sanyo Shinkansen electric multiple-unit train, the suspension components of the bogies are successfully developed which improve the damping ratio of lateral body hunting motion. The result of field tests shows that the frequency of lateral body acceleration decreases about 1/1O as compared with the original bogie.

著者

近藤 康治

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.60, no.467, pp.1388-1389, 1957-12-05 (Released:2017-06-21)

著者

市川 暉 兵頭 弘晃 琵琶 哲志

出版者

一般社団法人 日本機械学会

雑誌

スターリングサイクルシンポジウム講演論文集 2019.22 (ISSN:24242926)

巻号頁・発行日

pp.C03, 2019 (Released:2020-06-25)

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A thermoacoustic engine model with heat exchangers is introduced to show how a product of heat transfer coefficient h and heat transfer area of heat exchanger A determines the output power of the engine. Effective hA values are determined from experiments and calculation in a thermoacoustic engine prototype. The experimental and calculation results are compared with the favorable hA values estimated in the model.

著者

松丸 隆文 福山 聡 佐藤 智祐

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.72, no.724, pp.3863-3870, 2006-12-25 (Released:2011-08-16)

参考文献数

31

被引用文献数

3 6

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This paper proposed the model to estimate the load on the lumber vertebra considering not only the value presumed from posture but also the increased amount by Valsalva maneuver of extrapolating from the vital capacity. The pressure force can be estimated to be reduced by about 30% by the effect of the abdominal pressure by using the proposed model as said so far. From the error of the presumed value of ground reaction force from an actual measurement, it is thought that the presumed accuracy of the lumbar vertebra load using the proposed model is smaller than 10%. Furthermore, two operations with extreme start-on posture were compared on transition of the compressive force and shear force on the lumbar vertebra. It was brought out that a start-on posture signficantly affects the maximum load on the lumber vertebra. The result suggests that optimal start-on posture may be between two postures.

著者

小夜 結利花 山田 崇恭

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 (ISSN:21879761)

巻号頁・発行日

pp.23-00082, (Released:2023-10-23)

参考文献数

21

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This paper presents a conceptual design approach for planar link mechanisms by utilizing continuum topology optimization based on micropolar continuum theory. To effectively simulate the behavior of link mechanisms as continuum elasticity, we introduce a mathematical model utilizing micropolar elasticity. Although topology optimization is commonly used for single mechanical components, extending it to mechanisms with multiple interconnected parts presents inherent challenges. To address these challenges, we model the link mechanism using micropolar elasticity, leveraging its bendiness-related material property, which can apply to topology optimization. Subsequently, we formulate a topology optimization problem to generate link mechanisms using our proposed model. The optimized structure achieves the desired motion and deformation characteristics like traditional linkages with proper degrees of freedom while minimizing the objective function that considers both output motion error and link compliance. The design variables of the topology optimization problem are defined using the Solid Isotropic Material with Penalization (SIMP) method, which is further updated using a gradient-based optimizer. The governing equations of linear micropolar elasticity are solved using the Finite Element Method (FEM). The effectiveness and validity of our proposed method are evaluated through numerical examples, which conclusively demonstrate its ability to synthesize the number, dimensions, and structure of link mechanisms.

著者

大畑 充 庄司 博人 清水 万真 谷川 博康 加藤 太一朗 野澤 貴史

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 (ISSN:21879761)

巻号頁・発行日

vol.89, no.926, pp.23-00168, 2023 (Released:2023-10-25)

参考文献数

18

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This study aims to develop a numerical simulation-based method for predicting ductile crack growth resistance curve (R-curve) for pre-strained components for rational assessment of ductile crack growth controlling fracture for pre-strained structural component with any plastic constraint. Experiments on R-curve of 3-point bend specimen with a shallow crack for steel pre-strained by 6% over uniform elongation provides that the pre-strain does not significantly reduce ductile crack initiation and growth resistance, even though the pre-strain induces disappearance of uniform elongation and work hardening together with drastic reduction in elongation. Observations of damage evolution in terms of micro-void formation indicate that ductile crack growth behaviors in both virgin and pre-strained steels are based on a micro-void nucleation-controlled ductile fracture mechanism. These experimental results demonstrate that the ductile damage model that we have already proposed for predicting R-curve for virgin steel that exhibits micro-void nucleation-controlled ductile fracture behaviors can be applicable for these virgin and pre-strained steels used. Thus, based on the previously proposed ductile damage model, a simulation-based method to predict the R-curve of pre-strained specimens only from the properties of virgin steel is proposed taking material degradation (change in strength and damage properties) due to pre-strain into account. The applicability of the proposed method is verified by showing the predicted R-curve for pre-strained steel are in good agreement with experimental results.

著者

大島 徹 藤川 智彦 熊本 水頼

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 C編 (ISSN:03875024)

巻号頁・発行日

vol.65, no.635, pp.2837-2844, 1999-07-25 (Released:2008-02-26)

参考文献数

13

被引用文献数

4

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Animals have various muscular as power souses and they, living in the gravitational environments, have very similar basic muscular arrangements in their muscular arrangements reflecting differences in their locomotive life styles. We have reported that the coordinating muscular activities among the three pairs of antagonistic muscles contributed to the output force direction control, in all round (360°) direction, the force/position control and the stiffness control at the endpoint of the extremities. In the present paper, relations between the differences in the muscular arrangements in animals and the differences in the characteristic differences in their locomotive styles were analyzed in terms of functional anatomy and of control engineering. The results obtained that the muscular arrangements in animals was reflected in their locomotive styles. All animals had the essential muscular arrangements to realize the force and the stiffness properties at the endpoint of the extremities.

著者

馬渕 清資 藤江 裕道 佐納 義久

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.58, no.551, pp.1068-1072, 1992-07-25 (Released:2008-02-21)

参考文献数

20

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In the present study, the relationship between the femoral head diameter and the body weight of animals is shown. The diameter of femoral heads of fifteen terrestrial mammalian animals were measured directly from their skeletons. The body weight of these animals was referred from literature. Additionally, both the mean values of the femoral head diameters and the body weights of Japanese adult men and women were referred from the literature. The logarithm of femoral head diameter of these animals were plotted against the logarithm of body weight. The positive correlation was significant (p<0.01). The gradient of the regression line was 0.29. It showed that femoral head diameter is proportional to (body weight) 0.29. By analysis, we showed that this relationship can be deduced from the condition of uniform contact pressure or uniform performance of squeezed-film lubrication.

著者

原 朝茂

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 (ISSN:00290270)

巻号頁・発行日

vol.26, no.171, pp.1581-1586, 1960-11-25 (Released:2008-03-28)

参考文献数

3

被引用文献数

5 7

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When a train enters into a tunnel, at first the pressure of the air immediately before the train head rises and the portion of the air with raised pressure spreads forward with a velocity nearly equal to that of sound. In other words the wave front, the boundary surface between the undisturbed air and the compressed air, moves forward, is reflected at the exit of the tunnel and comes back to the train head. In the present paper the aerodynamic phenomena, during the time interval from the instant of the train head entering into the tunnel to the instant either its tail end coming into the tunnel or the wave front being reflected back to its head, whichever occurs earlier, are treated theoretically. The air is assumed to be compreesible and inviscid. The velocities and pressures of air in each portion of the tunnel are calculated. The pressure drag of the train is also obtained. It is interesting to note that the effect of compressibility of air is remarkable in spite of a comparatively low speed of train.

著者

松田 明子 景山 一郎 栗谷川 幸代 原口 哲之理 金子 哲也 小林 祐範 村山 哲也

出版者

一般社団法人 日本機械学会

雑誌

交通・物流部門大会講演論文集 2019.28 (ISSN:24243175)

巻号頁・発行日

pp.2202, 2019 (Released:2020-05-25)

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In this research, we investigate an adaptability of drivers to a personal mobility vehicle (PMV) using lean mechanism. In order to evaluate PMV with a lean mechanism considering driver's feeling, the purpose is to establish an evaluation method in human-car system. Experiments were conducted with multiple vehicle characteristics using a driving simulator. In this report, we analyzed for the steering angle focused on the input of the driver. First, it was confirmed that the steering angle really obtained with DS depends on the steering characteristics. Next, we confirmed that the tendency of the trajectory was different from the difference in equivalent preview time. Finally, the frequency characteristics of the adjustable steering were examined. As a result, there was a difference in reproducibility. And this difference may be a method of expressing driver characteristics.