著者

田村 伊知郎 松浦 真一 嶋津 龍弥 木村 康治

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.17-00403, 2018 (Released:2018-06-25)

参考文献数

11

---

The ductility factors of nonlinear SDOF systems at Service Limits Ds “using elastic analysis design” in JEAC4601 are investigated, and it was confirmed that the ductility factors depend on the natural frequencies of systems, seismic motions and constant loads. Based on the above results, an acceptance criterion of components to prevent ductile failure and plastic collapse is proposed. The criterion is given as a limit of ductility factor for Service Limits Ds “using elastoplastic analysis design”. The proposed limit of ductility factor allows single state for nonlinear systems, and doesn't depend on the natural frequencies of systems, seismic motions and constant loads.

著者

山田 和明 保田 俊行 大倉 和博

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.17-00288, 2018 (Released:2018-06-25)

参考文献数

28

---

The field of multi-robot systems (MRSs), which deals with groups of autonomous robots, is recently attracting much research interest from robotics. MRSs are expected to achieve their tasks that are difficult to be accomplished by an individual robot. In MRSs, reinforcement learning (RL) is one of promising approaches for distributed control of each robot. RL allows participating robots to learn mapping from their states to their actions by rewards or payoffs obtained through interacting with their environment. Theoretically, the environment of MRSs is non-stationary, and therefore rewards or payoffs learning robots receive depend not only on their own actions but also on the action of other robots. From this point of view, an RL method which segments state and action spaces simultaneously and autonomously to extend the adaptability to dynamic environment, named Bayesian-discrimination-function-based Reinforcement Learning (BRL) has been proposed. In order to improve the learning performance of BRL, this paper proposes a technique of selecting either of two state spaces: one is parametric model useful for exploration and the other is non-parametric model for exploitation. The proposed technique is evaluated through computer simulations of a cooperative carrying task with six autonomous mobile robots.

著者

堀 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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.17-00555, 2018 (Released:2018-06-25)

参考文献数

19

---

The conserved scalar and progress variable have been modified and proposed for spray and engine combustion simulation with chemical kinetics. The global equivalence ratio (GER) and progress equivalence ratio (PER) were proposed as the conserved scalar and progress variable in multi-zone model for engine simulations with chemical kinetics (Babajimopoulos et al., 2005). The combination of GER and PER work in lean mixture without EGR gas. But these would not work under rich mixture or EGR gas conditions. Thus, the modified GER is proposed to apply the EGR gas conditions where CO2 and H2O mix in air. Furthermore, the progress variable based on the chemical energy also proposed with modified GER. The zero-dimensional combustion simulations are done under constant pressure and adiabatic conditions to validate the proposed indexes. The reaction mechanism is the detailed chemistry of n-dodecane. That consists of 1,255 chemical species and 3,075 reactions. The results show that the conventional GER works in any mixture as conserved scalar and is good agreement with equivalence ratio under the ambient gas of air. But, the conventional GER overestimates equivalence ratio in lean mixture and underestimates equivalence ratio in rich mixtures. The modified GER is good agreement with equivalence ratio under the ambient gas of air and EGR gas including CO2 and H2O, regardless of lean and rich mixtures. The results also indicate that the PER works in lean mixtures. But that do not work in stoichiometric and rich mixture. The progress variable based on the mass fraction of some chemical species (Van Oijen and De Goey, 2010) works in any mixture, but the that can not compare the reaction progress between different GER conditions. The proposed progress variable works in any mixture and compares the reaction progress at different GER conditions quantitatively.

著者

伊澤 精一郎 磯 拓朗 西尾 悠 福西 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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.18-00132, 2018 (Released:2018-06-25)

参考文献数

23

被引用文献数

1

---

Behaviors of liquid films scattering from a disk-type or cup-type rotary atomizer are studied using computations based on the three-dimensional Smoothed Particle Hydrodynamics (SPH) method. To reduce computational costs while maintaining a high spatial resolution, the computational domain is limited to a fan-shaped region near the edge of the atomizers using a periodic boundary condition in the circumferential direction. Steady inflow is considered as the inlet condition. In both disk- and cup-type cases, the liquid film leaving the atomizer edge becomes wavy in the circumferential direction and forms elongated ligaments, which break up into droplets. When the atomizer is equipped with grooves on its outer edge, the process of ligament formation and droplet break up is strongly affected by the number and shape of the grooves, particularly for the cup-type atomizer, in which the centrifugal force works more effectively. Two ligament formation patterns are observed: one ligament from each groove and a pairing of ligaments from two neighboring grooves. Droplets of uniform sizes are likely to be generated when the former pattern appears. The results suggest that droplets of uniform sizes can be obtained by choosing the appropriate shape and number of grooves.

著者

西尾 宣俊 稲葉 真一 吉田 雄太 佐藤 暁拓 田向 剛 高木 哲郎 飯田 誠

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.862, pp.18-00042, 2018 (Released:2018-06-25)

参考文献数

15

---

In case of analyzing the wind turbine design conditions and power productions accurately, the wind data at hub height is generally ideated for simulation. Recently, due to the increase in the size of the wind turbine, it is difficult to measure wind data of hub height by the cylindrical observation tower. Therefore, lattice tower mast is adopted and there are cases where high altitude measurement is performed instead of cylindrical tower mast. However, even in case of measuring wind data using lattice tower mast, there are some uncertainty of flow distortions by tower shadowing. This paper shows a study on wind speed correction method of lattice tower mast using CFD simulations (Fluent). As a result of performing the wind speed correction using the inflow wind speed ratio by CFD calculation, the uncertainty of corrected wind speed fell by less than 1 % which is recommended by IEC 61400-12-1.

著者

細谷 和輝 高橋 一成 大家 渓 岩森 暁

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.862, pp.17-00561, 2018 (Released:2018-06-25)

参考文献数

20

被引用文献数

2

---

Surface modification of polystyrene (PS) dish used as a cell culture substrate is an indispensable strategy to enhance cell adhesion. In general, plasma treatment is employed to enhance the hydrophilic nature on the PS dish surface, and sterilization treatment of the PS dish is performed after the plasma treatment. We reported on a simultaneous process of surface modification and sterilization on the PS dish in a sterilization bag by using active oxygen species (AOS) generated via ultraviolet (UV) lamps, whose wavelength are 185 and 254 nm respectively. Herein, we attempt to investigate the dependency of the distance between UV lamp and PS dish on the surface modification by using the AOS. After exposure of AOS, the oxygen content of the PS dish was increased, whereas the water contact angle was decreased along with the decrement of the distance between PS dish and UV lamp owing to increase in the AOS concentration. Cell adhesion was also enhanced with decrease of the distance between PS dish and UV lamp compared with untreated PS. Especially, chemical states such as atomic concentration and chemical bonding affect cell adhesion rather than the surface wettability. Illumination of the UV lamps and AOS concentration at the PS dish surface affects the resultant cell adhesion.

著者

中佐 啓治郎 山本 旭宏 李木 経孝

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.17-00360, 2018 (Released:2018-06-25)

参考文献数

17

被引用文献数

1

---

Argon ion sputter-etching of SUS420J2 and SUS316 stainless steels was carried out at a power of 250W for 10.8ks to form cone-shaped sharp protrusions with bottom diameter of 10-30 μm and fine quasi-column-shaped protrusions with diameter smaller than 500 nm respectively by using a radio-frequency magnetron sputter-apparatus. Effects of two types of plasma-nitriding on gripping ability were examined; one is the nitriding of both steel specimens using nitrogen gas of 0.53 Pa mixed with argon gas of 0.67 Pa at a power of 50W for 1.8 ks to maintain the original sharpness of protrusions, and another is the nitriding of SUS420J2 steel specimen using only nitrogen gas of 1.2 Pa at a power of 200 W for 7.2 ks to obtain the cone-shaped protrusions with round top. The coefficient of static friction, or gripping ability, of the plasma nitrided sharp protrusions of SUS420J2 steel specimen to polyethylene, polyvinyl-chloride, polyethylene-naphthalate sheets and a copy paper was about 1.8, 2.4, 1.1 and 1.5, respectively, at a large nominal compressive stress of 18 kPa. The reason for such large frictional coefficients is due to localized deformation of sheet under the sharp protrusions or piercing of the protrusions into the sheet. Although the sharp protrusions were partly broken, the frictional coefficients of these sheets were still about 1.6, 1.8, 1.1 and 1.4 after the second series of tests, which are more than twice as large as that of the specimen ground with #100 emery paper. The plasma-nitrided round protrusions of SUS420J2 steel and the fine protrusions of SUS316 steel were not broken during the friction tests of the polyethylene sheet and the copy paper but the frictional coefficients are smaller than those of the sharp protrusions. The protrusions with large frictional coefficients can be applied to the surface of a frictional conveying roll.

著者

住田 杏 田中 宏明 池田 忠繁

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.17-00525, 2018 (Released:2018-06-25)

参考文献数

11

---

A new method of driving and controlling multiple piezoelectric actuators individually with a single power supply unit using variable resistors was developed, and its effectiveness was investigated. This method provides effective high-accuracy shape control under weight limitation as each actuator can have a desired voltage applied individually from the single power supply unit using variable resistors. It was observed that the proposed method can drive piezoelectric actuators without degrading their operational performance when compared to representative actuator driving methods. Moreover, a shape control utilizing the proposed method was demonstrated to be more accurate than the conventional grouping method of multiple piezoelectric actuators, by numerical analysis and experiments on cantilever beams.

著者

近藤 稔

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.862, pp.17-00594, 2018 (Released:2018-06-25)

参考文献数

16

被引用文献数

4

---

Railway vehicles are equipped with many kinds of machines such as traction diesel engines and their failures sometimes lead to service disruptions and accidents. Vibration monitoring systems are expected to prevent their failures by detecting their abnormalities at an early stage. In order to make an effectual action after abnormal vibration detection, it is necessary to make a root cause diagnosis. To address this issue, a simple diagnosis method is proposed in this paper. In the method, a measured vibration octave spectrum is divided into three frequency bands and abnormality detections are conducted for the spectra to narrow down the root cause of the vibration. A one class classification method, which is an anomaly detection method in machine learning, is used in the abnormal vibration detection to make a general purpose vibration monitoring system. In addition, the ratios of abnormal vibration are calculated for the three frequency bands to show the progress of the fault. The effectiveness of the method is verified using vibration data acquired on simulated abnormality tests of traction diesel engines, i.e., auxiliary drive shaft failure test and engine abrasion test. The test results show that the proposed method is effective in detecting the abnormality and diagnosing the cause and the degree of the failure.

著者

嶋脇 聡 須田 拓也 中林 正隆 杉本 英治

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.862, pp.18-00131, 2018 (Released:2018-06-25)

参考文献数

37

---

The neck is an important body part that links the head and chest sections. However, very few analyses of cervical movement derived from muscle contractions have been conducted with numerical simulation. This study aimed to construct a multi-body model of the neck comprising the bones, muscles, and ligaments (including the intervertebral disc) and to apply flexion and extension movements to analyze the behavior of each cervical segment. We created bone models (including cervical vertebrae C1-C7) from X-ray computed tomography (CT) images of the upper half of the human body. Each bone model was bound by 17 types of ligaments constructed as 51 wire models. We set six types of muscles as the protagonists for neck flexion and 12 types for the neck extension. Muscle strength was defined with a parallel contraction element model and an elastic element model. The intervertebral discs represented five spring models with repulsion characteristics on compression and attraction characteristics on extension. The neck section could flex up to 38.1° and extend up to 61.0° with contraction in the flexor and extensor models. The maximum cervical segment angles on flexion and extension were measured at C0-C1 and C4-C5, and their contribution rates were 20.7% and 19.3%, respectively. Each cervical segment angle when flexing and extending closely matched the experimental results measured by other studies. The centers of rotation for cervical segments from C2-C3 to C4-C5 on maximum flexion were different from those in previous experimental result. This may be because of the settings pertaining to the interspinous ligament, nuchal ligament and supraspinous ligament. On the other hand, our results for maximum extension were consistent with past experimental result. An improved neck model will allow the analysis of cervical segment movement through the joint restrictions based on damage to the ligaments and muscles or arthrodesis when flexing and extending.

著者

坂上 賢一 加藤 和樹 岸部 駿之介

出版者

一般社団法人 日本機械学会

雑誌

M&M材料力学カンファレンス

巻号頁・発行日

vol.2017, 2017

---

<p>Multicycle indentation test is applied to measure viscoelastic characteristic. In multicycle indentation test, indentation test is repeated at the same position on the specimen, and the mechanical characteristics are measured from on the impression. Therefore, the evaluation formula is introduced for the indentation measurement on the impression. An undeformed specimen and plastically deformed specimen of ABS resin are used. The result shows the measured creep compliance by multicycle indentation test is in good agreement with that by uniaxial tensile test. Thus, the proposed method can measure viscoelastic characteristics with high accuracy. Measured characteristics indicate that the undeformed specimen is isotropy but the plastically deformed specimen is anisotropy. This fact implies the development of anisotropy by reorientation and elongation of polymer chains during uniaxial plastic deformation.</p>

著者

魚井 成晃 黒河 愛 廣瀨 悠二 小笹 俊博

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.18-00006, 2018 (Released:2018-06-25)

参考文献数

19

---

Elastohydrodynamic lubrication of a journal bearing has been usually calculated with bearing deformation. In this study, crank-pin deformation is included in addition to the bearing deformation of con-rod big-end. The calculated results are shown with and without the crank-pin deformation and the effects of the crank-pin deformation on calculated results are discussed. The effects of the crank-pin deformation appear after compression TDC during low speed operation and near suction TDC during high speed operation.

著者

下條 信輔

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.109, no.1049, pp.261-264, 2006-04-05 (Released:2017-06-21)

参考文献数

23

被引用文献数

1 4

著者

山崎 康彦 重松 研太 翁 嘉華 小島 史夫 髙田 祥三

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.862, pp.17-00533, 2018 (Released:2018-06-25)

参考文献数

14

被引用文献数

2

---

Current production systems are required to stay up-to-date with the changing market conditions. To date, most conventional flexible systems are dependent on human flexibility. However, the demand for flexible automation systems is increasing because of rising labor costs and higher quality requirements, even in emerging countries. To implement automation systems in the unpredictable market, cost reduction is essential to reduce the investment risk. However, there is no systematic design method for reducing the cost of automation systems. Thus, in this study, we propose a new method for the design of material handling systems, wherein the waiting time of the equipment is reduced by grouping the operations and allocating certain equipment to each group. The proposed design method uses a genetic algorithm to determine the optimal grouping of operations on the basis of the equipment cost and cycle time. The design method is then applied to an automobile engine control unit to verify its effectiveness.

著者

海津 浩一 伊藤 脩平 日下 正広 木村 真晃 木之下 広幸

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.862, pp.17-00485, 2018 (Released:2018-06-25)

参考文献数

10

被引用文献数

1

---

Joining of plastics and light metals contributes to the reduction of a product weight. In this study, the punching rivet method was applied to joining of an acrylic resin sheet and an aluminum alloy sheet. The punching rivet method can join the sheets without drilling. The riveting process of this method is constituted of the punching process of the sheets using the rivet shank and the fastening process of the sheets using the rivet and the rivet holder. The sheets are fastened by using the plastic deformation of the rivet shank. From the observation of the joints made by the punching rivet method, it was found that the acrylic resin sheet of the joint had no crack and out-of-plane deformation of the joint was small. From the results of the joint strength tests, it was considered that the joint made by the punching rivet method had high strength due to the effect of the pressures on seating faces of the rivet and the rivet holder. As a result, the punching rivet method was effective to join the acrylic resin sheet and the aluminum alloy sheet.

著者

御手洗 毅 山浦 弘 小野 京右

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.723, pp.3576-3583, 2006-11-25 (Released:2011-03-04)

参考文献数

5

被引用文献数

1

---

Rhönrad is a gymnastic equipment that is interesting in terms of dynamics and control. We presented an analytical model and governing basic equations of the Rhönrad mechanism with a human body model. Then, a control method named as Synchronous control was proposed. In this control method, the human body moves synchronously with the rotation angle of the Rhönrad. The motion caused by Synchronous control was numerically analyzed. After that, a standalone miniature Rhonrad robot that consisted of three gyro sensors, an actuator, a micro-computer and batteries was manufactured. The validities of the Synchronous control were shown by experiments with the robot.

著者

田辺 郁男 高橋 宗一郎 高橋 智

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.862, pp.18-00171, 2018 (Released:2018-06-25)

参考文献数

16

被引用文献数

1

---

The Design of Experiments (DOE) is a method that is widely used due to its effectiveness to select optimum conditions in the design stage of product development. On the other hand, a fast, low cost, labor saving and energy-saving innovative development is also required in industry. In this research, a program for quickly searching the optimum condition using design of experiments is developed and evaluated. Relationships between each parameter and the final property are firstly cleared for each formula by using the design of experiments. Then the optimum conditions for each parameter were decided by using these formulas in a program. The optimum final property with each optimum level value were calculated. In addition, the optimum condition for cooling system using alkaline water mist was investigated for evaluating this program in an experiment. It is concluded from the result that (1) the program using the design of experiments was useful for fast development process, (2) this program could quickly and accurately decide the optimum cooling condition for cooling system using alkaline water mist.

著者

井田 富夫 杉谷 恒也

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.45, no.399, pp.1650-1658, 1979-11-28 (Released:2008-03-28)

参考文献数

19

被引用文献数

1 5

---

油中の単一気ほうが急激な圧力変化を受けて膨張・収縮する際の気ほう径と圧力との関係を実験的に調べ、これを理論解と比較してつぎのことを明らかにした。(I)油圧油の基油中では数ms内に1気圧という急激な圧力変化を受ける場合にも、気ほう界面に拡散による相変化が生じる。(ii)基油に微量の界面活性剤を添加すると拡散現象は抑制される。(iii)気ほうの理論解析には表面粘性による界面変形抵抗を考慮する必要がある。

著者

竹村 文男 矢部 彰

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.64, no.623, pp.2168-2173, 1998-07-25 (Released:2008-03-28)

参考文献数

15

被引用文献数

5 5

---

The gas dis solution process of a spherical rising carbon dioxide bubble in water was investigated experimentally and numerically. We developed an experimental system that use a CCD camera coupled with a microscope to follow the rising bubble. By measuring the bubble size and the rising speed from the bubble motion data captured by a personal computer, we could precis ely estimate the drag coefficients and the Sherwood number for the dis solution of gas bubbles at Reynolds numbers below 100. The experimental results show that the drag coefficients of the carbon dioxide bubble in water show the same value of solid particle even when we use relatively clean water. We also numerically estimated Sherwood number for dis solution of gas bubbles in an infinite liquid by directly solving the Navier-Stokes equation and diffusion equation. The experimental and numerical results are in good agreement. Moreover, we compared the experimental results with a proposed equation for estimating the drag coefficients and Sherwood number and clarified the applicable region of the equation.

著者

安井 学 中野 一史 黒内 正仁 川野 伸一 金子 智

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.862, pp.18-00091, 2018 (Released:2018-06-25)

参考文献数

23

---

SU8 is a negative photoresist shows superior characteristics of heat resistance and chemical resistance. And, it is used to make high-aspect ratio micro structures such as master of electroforming. However, it is extremely difficult to remove SU8 from substrate. Researchers have investigated a means of SU8 removal. Therefore we proposed a new SU8 removal method “DI water (H2O) and lithium chloride (LiCl) doped NMP” which promises swelling furtherance of SU8, and we demonstrated that the new method could remove fine SU8 patters from substrate at proper level. The mechanism of SU8 fine patterns removal is presented as follows. A doped NMP broadens the width of SU8 patterns by swelling effect and reduces buckling stress of SU8 patterns. SU8 patterns reducing buckling stress increases the potential of buckling.