著者

島田 慶一 萩原 義裕 盧 忻 アデルジャン イミティ ナンタナー ルンサワッディサップ

出版者

一般社団法人 日本機械学会

雑誌

東北支部総会・講演会 講演論文集 2019.54 (ISSN:24242713)

巻号頁・発行日

pp.139, 2019 (Released:2019-09-25)

著者

山田 崇恭 西脇 眞二 伊賀 淳郎 泉井 一浩 吉村 允孝

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.75, no.759, pp.2868-2876, 2009-11-25 (Released:2017-06-09)

参考文献数

21

被引用文献数

1 2

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In structural designs considering thermal loading, to control thermal stress and minimize decreases in material strength at high temperatures, it is important to maximize the thermal diffusivity of structures, in addition to the usual maximization of stiffness that optimal designs achieve. This paper presents a new level set-based topology optimization method for thermal problems with generic heat transfer boundaries in a fixed design domain that includes design-dependent effects, using level set boundary expressions and the Finite Element Method. First, a topology optimization method using a level set model incorporating fictitious interface energy is briefly discussed. Next, an optimization problem is formulated using the concept of total potential energy to address the design of mechanical structures that aim to minimize the mean temperature of the structure under thermal loading. An optimization algorithm that uses the Finite Element Method when solving the equilibrium equation and updating the level set function is then constructed. Finally, several numerical examples are provided to confirm the utility of the proposed optimization method.

著者

齊藤 亜由子 宮脇 和人 小松 瞭 巖見 武裕

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.84, no.865, pp.18-00263, 2018 (Released:2018-09-25)

参考文献数

20

被引用文献数

1

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This paper describes the use of nine-axis motion sensors to evaluate the motion sensor position on the thigh and lower leg during walking. The motion sensors are mounted on a subject's body using adhesive tape. The muscles constantly relax or contract because of human movement. Therefore, joint angle estimation using motion sensors produces different accuracy depending on the position where the motion sensor is mounted. Evaluating the motion sensor position is important for improving the joint angle estimation accuracy. For this study, the authors used six nine-axis motion sensors and a 3D motion analysis system to assess walking exercise. Three motion sensors were mounted to the thigh; three were mounted to the lower leg. The knee joint angle was estimated using a sensor fusion algorithm that corrected the centrifugal acceleration and the tangential acceleration in the acceleration sensor output. We evaluated the accuracy of knee joint angle estimation by comparing the nine-axis motion sensor results and the 3D motion analysis system results. Results demonstrated the possibility of high-accuracy estimation when the motion sensor is attached to a position 50% or 75% from the upper end of the thigh and another sensor is attached to a position 25% or 50% from the upper end of the lower leg.

著者

松永 拓也 越塚 誠一 保坂 知幸 石井 英二

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.85, no.877, pp.19-00186, 2019 (Released:2019-09-25)

参考文献数

37

被引用文献数

1

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In this paper, we proposed a new particle method for numerical simulation of droplet dynamics. In the proposed method, the moving surface mesh is used to define interface between gas and liquid. The volume enclosed by the mesh represents the liquid droplet, and the outer domain is inactive gas with constant pressure. The incompressible liquid flow is calculated using a particle method, in which spatial derivatives are evaluated using an arbitrary high order accurate scheme. On the free surface, the surface stress balance equations, including surface tension and viscous stress, are adopted for the boundary conditions. Deformation of the gas-liquid interface is explicitly calculated by surface nodes that move in a Lagrangian fashion. Surface tension force is directly evaluated with high accuracy on each node utilizing the mesh shape. As numerical verification, simulations of three benchmark problems, namely circular patch test, Laplace pressure test and 2D droplet (liquid column) oscillation problems with different oscillation modes, have been carried out. The computation results were compared with the theoretical solutions, and excellent agreements were obtained. As a result, high accuracy and validity of the proposed computational method were confirmed.

著者

山崎 容次郎 横川 隆一 積際 徹 原 敬

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.74, no.740, pp.867-875, 2008-04-25 (Released:2011-03-04)

参考文献数

17

被引用文献数

2 4

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This paper proposes a new switching method of control mode for a robot manipulator coming in contact with environment that has elasticity. First, the basic concept of the switching of the control mode in a robot manipulator is explained. Second, we propose a new method of switching the control mode that selects the control mode at the intersection of “Characteristic curve of position and force” and “Target value of the work composed by the desired value of position and force”. Next, the switching algorithm based on this method is obtained about a certain work coordinate with a Multi-DOF robot manipulator. In this paper, the switching method is named “A Method for Switching Control Mode Based on Position and Force Errors”. Furthermore, when a One-DOF robot manipulator driven by DC servo motor with reduction gears using an elastic joint came in contact with the object that has elasticity, the simulation and the experiment on various angle and torque controls were done. As a result, it is shown that the proposed switching method is useful and has stable and flexible characteristics.

著者

猫本 善続

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.99, no.936, pp.943, 1996-11-05 (Released:2017-06-21)

著者

炭竈 美穂 梅原 徳次 野老山 貴行 上坂 裕之

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.80, no.811, pp.SMM0038, 2014 (Released:2014-03-25)

参考文献数

13

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Disc brake is one of the most important auto mobile components and the toughest frictional components. Nowadays, the lightweight disc brake is needed for better fuel-efficient. To reduce the weight, high frictional and low aggressive brake pad is required. However, generally high friction cannot provide low wear of counter-part, therefore to make such brake pad is difficult. In addition, including many kinds of materials such as abrasive, binder, filler and so on, we cannot design it theoretically. In order to overcome these issues we focused on abrasive shape in brake pad, especially focused on open angle of abrasive φ and the important index “degree of wear fab”. If degree of wear fab decreases with open angle φ of abrasive and reduction of wear is more than reduction of friction, we can propose the high frictional and low aggressive brake pad which includes small open angle abrasive. In order to validate our proposals, we conducted the scratch test using Vickers indenter and Knoop indenter. As a result of the scratch test, we clarified that the ratio of wear coefficient to friction coefficient K / μ is correlated with degree of wear fab, and in the region of ploughing and wedge, degree of wear fab decreased with decreasing open angle φ. Due to these phenomena, the ratio of wear coefficient to friction coefficient K / μ decreased with decreasing open angle φ in the region of ploughing and wedge. Thus it was valid that small open angle abrasive provides high friction and low aggressiveness.

著者

清水 聡 木下 英二 亀田 昭雄

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会九州支部講演論文集 2010.63 (ISSN:24242780)

巻号頁・発行日

pp.357-358, 2010-03-15 (Released:2017-06-19)

著者

金子 和喜 吉本 康文

出版者

一般社団法人 日本機械学会

雑誌

北陸信越支部総会・講演会 講演論文集 2008.45 (ISSN:24242772)

巻号頁・発行日

pp.253-254, 2008-03-01 (Released:2017-06-19)

著者

林 義裕 若林 千裕 古畑 朋彦 新井 雅隆

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.72, no.716, pp.1021-1028, 2006-04-25 (Released:2011-03-03)

参考文献数

31

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Mixture formation of diesel spray impinged on an extruded surface, which was a top of cylindrical column, was investigated experimentally. A diesel spray was impinged vertically to the extruded surface. The behaviors of impinged spray were observed using a high-speed drum camera. A spray volume was estimated from the photographs. Effect of cylindrical column diameter on spray behavior was investigated. Adhering fuel was measured by a primitive “wiping by paper and mass measuring” method under various conditions. Air-fuel ratio in spray was calculated from spray volume and adhering fuel. As the result, the behavior of diesel spray impinged on an extruded column was strongly influenced by the diameter of the extruded column. From the measured results, it is clear that the air-fuel ratio in spray in the extruded column diameter of 45 mm was larger than those in the other columns.

著者

藤田 尚毅 永倉 喜一郎 角掛 繁

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.53, no.486, pp.654-658, 1987-02-25 (Released:2008-03-28)

参考文献数

8

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In this paper, we give an account of the studies of gas oil-water-methanol stable emulsified fuel, and the influence of this fuel on pre-combustion type 4-cycle diesel engine performance. By selecting a suitable surfactant and exposing the emulsion to surpersonic waves, the authors succeeded in preparing a stabilized gas oil-water-methanol emulsion. By making use of this emulsified fuel, NOx concentration and smoke in the exhaust gas from the diesel engine were decreased. In the test range, the influence of the water in the emulsion on the engine performance was greater than that of methanol. Moreover, we investigated the influence of a change in the fuel injection timing.

著者

天寅 喬文 渕端 学

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.85, no.875, pp.18-00399, 2019 (Released:2019-07-25)

参考文献数

8

---

In recent years, NOx and soot contained in the exhaust gas of diesel engines become problems. Currently they are elutriated by exhaust gas aftertreatment devices, which make the engine system more complicated. Therefore, we focused on emulsion fuel, which is known as one of the simultaneous reduction technology of NOx and soot. Although emulsion fuels are generally characterized by its water content, some literatures report that the effect on the diesel engine performance could not be controlled by the water content properly. Therefore, we focused on dispersed water droplet diameter as the other factor. In this study, we prepared emulsion fuels of different water droplet diameters and investigated the exhaust gas and power performance of a diesel engine with these fuels. The emulsion fuels consist of light oil, water and surfactant. We added 2.0 vol% of surfactant whose HLB value was adjusted to 6.0 to light oil. The water content was 10 and 15 vol%. We prepared emulsion fuels of three different mean dispersed water droplet diameters. The test fuel was 6 types of emulsion fuel (3 kinds of dispersed water droplet diameter, water content 10 and 15 vol%) and light oil. The diesel engine used in our experiment was of air-cooled, single-cylinder, jerk pump driven direct injection type. The displacement is 320 cc. We measured in-cylinder pressure, ignition delay, exhaust gas emission (NOx, Soot and CO) and power performance (Output power and Thermal efficiency). We found a relationship between the Sauter Mean Diameter of dispersed water droplets (DS.M.D.) and each parameter. The smaller DS.M.D. is, the more the NOx and soot are reduced. On the other hand, the bigger DS.M.D. is, the higher the output and thermal efficiency are.

著者

中川 洋 森 俊一 遠藤 浩之

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.61, no.590, pp.3554-3560, 1995-10-25 (Released:2008-03-28)

参考文献数

10

被引用文献数

1 1

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This paper describes the effects of water-emulsified fuel on diesel spray combustion. Theoretical analysis and numerical simulation show that the high momentum of water-emulsified fuel spray per unit mass due to lower calorific value leads to higher air entrainment into spray than in the case of ordinary fuel. The experimental results show that these effects cause a reduction in the temperature of the combustion reacting zone of water-emulsified fuel spray, and a shortened combustion duration, and less formation of soot and nitric oxide in a diesel engine.

著者

神本 武征 高橋 浩 小林 治樹 松岡 信

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.49, no.440, pp.901-908, 1983-04-25 (Released:2008-03-28)

参考文献数

15

被引用文献数

2

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急速圧縮装置を用いて平面に衝突するディーゼル火災の対流熱伝達に関する実験を行った.衝突面の熱流束は,通常の等温ガス噴流の衝突の場合と異なり,よどみ点から半径方向にほぼ一定に分布する.これは,よどみ点から半径方向に減少する熱伝達率と,半径方向に向かって燃焼が進行するにつれて増加する熱落差とが相殺し合う結果と解釈される.衝突面への熱損失率は熱発生率の約10%であり,両者の時間経過曲線は良く似ている.

著者

李 世文 榎本 良輝 神本 武征 小堀 繁治 吉川 英樹

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.63, no.609, pp.1814-1819, 1997-05-25 (Released:2008-03-28)

参考文献数

14

被引用文献数

3 3

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Combusting and evaporating diesel sprays, impinging on the wall of a square combustion chamber were obtained in a rapid compression machine. The temperature fluctuations at many locations on the impinging wall surface were measured using thin-film thermocouples, and the local heat fluxes were calculated from temperature history records. The motion of the impinging flames was photographed from two directions using a high speed camera, through optical windows attached to the square chamber. It was shown that the local heat flux increases as the fuel injection pressure and the ambient density increase, and is approximately proportional to 0.6-1.0th power of the injection velocity. However, it decreases downstream from the stagnation point. The ratios of the local heat fluxes between the combusting and evaporating sprays estimated using a two-zone model for the characteristic temperature were found to be close to the measured values.

著者

川島 進 渡邉 豊

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:18848354)

巻号頁・発行日

vol.77, no.778, pp.2376-2388, 2011 (Released:2011-06-25)

参考文献数

24

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The center of gravity of a moving train differs time to time due to variety of number of passengers on board. There can be significant difference of 3D-locations of the center of gravity on the same train between at rush hour time and at off peak one. It is essential to detect the location for preventing rollover accidents of trains on which the critical speed of rollover for them depends. In this respect, this paper applies the innovative new theory of detecting 3D-locations of the center of gravity of a moving object for trains, which was invented by the second author of this paper and abbreviated as D3DCG(1). D3DCG was created by the concept of motion dynamics of a ship floating on water. This paper assumes that similar condition can occur while a train is moving straight at constant speed. Based on this assumption, the authors measured the vertical acceleration and the roll rate of moving trains, which were to be applied to D3DCG for trains, and were successfully able to detect 3D-locations of the center of gravity on trains by D3DCG.

著者

塩谷 義

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 2018 (ISSN:24329509)

巻号頁・発行日

pp.C-21, 2018 (Released:2019-05-25)

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The turning in the ballroom dancing is analyzed in the mechanical point of view, comparing the left turn and the right turn. Reverse Turn and Natural Turn in Waltz are taken as examples. In the syllabus of ballroom dancing, the both turns are described as just exchanging the terms “right” and “left” each other. However, in fact some different feelings exist in the left and the right turns. This causes mainly come from the couple holding form which is a characteristic of modern ballroom dancing. The movements of dancers during the turns are mechanically analyzed focusing the moving paths of the dancers and the inertia forces in the direction of the partner during the turn. The results show different patterns of movements and forces in the left and the right turns. The parameters affecting the left and right difference are also shown, suggesting improvement ways of the dancers’ movements. The left and right difference caused by the Line of Dance is also explained.

著者

中山 昇 望月 隆介 澤本 一樹

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.79, no.802, pp.827-837, 2013

被引用文献数

2

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Porous materials have attracted attention because they exhibit a wide range of useful properties. They are mainly manufactured using either a precursor or a melting method. However, the processes involved are complicated because of the need for a primary extrusion step and the addition of a pore-forming agent. Also, because of the large amount of energy required for the sintering step, these methods represent a large environmental burden. To solve this problem, the present study focused on the formation of solidified porous aluminum by a reaction between pure aluminum powder and pure water, without the need for sintering. The effect of the formation temperature was investigated by measuring the amount of hydrogen released during the reaction, and the density and microstructure of the final materials. X-ray diffraction measurements and compression tests were also carried out. The results of the microstructural observations and X-ray diffraction measurements indicated that, during the reaction, a bayerite layer was formed on the surface of the powder particles. With increasing temperature, the reaction was found to start more quickly and more hydrogen was released. Furthermore, from the compression tests, the initial maximum stress, the plateau stress and the absorbed energy decreased with increasing formation temperature. The results of the present study indicated that it was possible to form highly porous aluminum using the proposed method.

著者

森山 淳

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:18848354)

巻号頁・発行日

vol.78, no.791, pp.2536-2548, 2012 (Released:2012-07-25)

参考文献数

10

被引用文献数

3 2

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For the clarification of the overturning behavior of railway vehicle exposed to strong cross wind, several experiments were done to study the effect of wind velocity and wind direction on the wheel unloading ratio. In this paper, the results of the experiment at a line in the Kanto region are described. In this line, strong wind is often observed, and various types of train are operated. To get useful knowledge about the improvement of the critical wind speed of vehicle overturning, data were analyzed in terms of the vehicle cross-sectional shape. Results of the experiment show that vehicle specifications, such as a car weight, or a bogie suspension are little effective for overturning, if there are no difference about the cross-sectional shape. Analyzed results of the experiment also show that depending on the cross-sectional shape, the behavior of wheel unloading ratio by strong wind is different. These results suggest the possibility of the superiority of round shape roof for improving the performance against overturning.

著者

大橋 博志 門脇 敏

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.799, pp.477-481, 2013 (Released:2013-03-25)

参考文献数

8

被引用文献数

1 1

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To investigate the front shape and fluctuation of cellular flames on a flat burner, we treated CH4/Air mixtures and two types of CH4/O2/CO2 mixtures. We obtained the front shape of cellular flames, i.e. the cell width and cell depth, by the planar laser-induced fluorescence of CH radicals (CH-PLIF) and measured the light emission to clarify the characteristics of fluctuation of premixed flames. As the flow rate of methane decreased, the cell width and cell depth became larger, and the size of attractors increased. Compared with CH4/Air mixtures, cellular fronts were observed at large flow rates of methane in CH4/O2/CO2 mixtures, and the trajectory of attractors was complicated. These were because of high intensity of diffusive-thermal instability resulting from the replacement of N2 with CO2.