著者

藤川 正毅 山辺 純一郎 小石 正隆

出版者

一般社団法人 日本機械学会

雑誌

計算力学講演会講演論文集

巻号頁・発行日

vol.2017, 2017

---

Industrial rubber, commonly used in the fabrication of tires and engine mounts, exhibits nonlinear viscoelastic behavior. In the design of these rubber products, it is important to capture the stress–strain responses under arbitrary loading conditions. However, the stress–strain responses exhibit complicated behavior, which depends on strain rate, strain history, strain amplitude, etc. The main purpose of this study is to develop a new constitutive model that captures the nonlinear viscoelastic stress–strain response of carbon-black-filled styrene-butadiene rubber vulcanizates (SBR-CB). In the assumed micro-mechanical network structure, we decomposed the isochoric free energy into the elastic equilibrium and the viscoelastic overstress response. Based on the results of our performance evaluation of various hyperplastic material models, we used an eight-chain model for the equilibrium network. For the nonlinear viscoelastic network, we used the micro-sphere model. The micro-stress/strain equation was assumed to be in simple phenomenological form, as reported by Miehe. For the revolution equation of the micro-inelastic strain, the Rendek and Lion model was employed. In addition, to reproduce the stress-strain relationship under from infinitesimal to 50% strain amplitude, the relaxation time depending on the strain amplitude of the free dangling chains was proposed as a new metric. The proposed model was able to practically and precisely reproduce the dynamic responses of SBR-CB25 under a wide range of applied strains and strain rates, was thermodynamically consistent for arbitrary deformation, could be implemented in commercial FEM software (Abaqus), and reproduced the stress-strain relationship under various experimental loading conditions.

著者

米須 清一郎 松田 昇一 加藤 純郎

出版者

一般社団法人 日本機械学会

雑誌

年次大会

巻号頁・発行日

vol.2017, 2017

---

<p>Impingement jets are often used for the cooling and heating of a surface or a body because a high heat transfer coefficient is obtained near the stagnation point of an impingement surface. Recently, as equipment becomes smaller, impingement jets have been utilized in narrow spaces. In such a case, the nozzle diameters and Reynolds number which based on the nozzle exit velocity also become tinier as a matter of course. Generally, in the case of measuring the heat transfer coefficient by using a thin heat transfer surface, heat loss, <i>q</i>_e due to heat conduction in the in-plane direction in the heating surface occurs. However, <i>q</i>_e has been considered inconsequential in the case of the common impinging jets having large diameters and with large Reynolds number. However, <i>q</i>_e may not be negligible in the case of impinging jets having a small diameter and with low Reynolds number. In this research, heat transfer characteristics using rows of impinging jets with small diameters and with low Reynolds number were investigated experimentally. The jet holes with the diameters <i>D</i> of 1, 2 and 3 mm were used. The experiments were performed with the relatively low Reynolds number range of 170~1460. The surface temperature of the impingement plate was measured using an infrared camera, from which heat transfer coefficients on the surface were obtained. It was found that the <i>q</i>_e needs to be considered in the case of impinging jets having small diameters and with low Reynolds number.</p>

著者

笠原 直人 林 眞琴

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:18848338)

巻号頁・発行日

vol.78, no.789, pp.583-598, 2012 (Released:2012-05-25)

参考文献数

39

被引用文献数

1

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Various kinds of thermal fatigue failure modes exist in nuclear power plant components. Main causes of thermal loads are structural responses to fluid temperature changes. These phenomena have complex mechanisms and so many patterns, that their problems still occur even though well-known issues. Among them, this paper treats high cycle thermal fatigue of branch pipes as the typical mode. Firstly, experimental and analytical researches are explained for thermal load evaluation. Through them, both numerical and kinematic methods were developed. Next chapter describes thermal fatigue strength studies on both crack initiations and propagations. They revealed the similarities of thermal crack initiations with mechanical ones and frequency characteristics of crack propagation. Finally, current status and future challenges are discussed for evaluation of actual plants.

著者

佐藤 俊之 阿部 梨恵 齋藤 直樹 永瀬 純也 嵯峨 宣彦

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.81, no.827, pp.15-00084-15-00084, 2015 (Released:2015-07-25)

参考文献数

13

被引用文献数

2 3

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This paper addresses position and path-tracking problems of robot manipulators subject to constraints on both the magnitude and difference of the control input. Along with the model predictive control (MPC), the disturbance observer (DOB) is used to compensate for disturbances and nominalize the plant dynamics. To constrain the total control input, which is the sum of the MPC output and DOB output, we adopt time-varying input constraints and construct a useful structure of the combined DOB-MPC system. The effectiveness of the proposed control scheme is validated through a few experiments using a real two-link manipulator.

著者

中山 万希志 奥井 博己 木村 尚人 栗屋 効典

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 (ISSN:21879761)

巻号頁・発行日

vol.84, no.857, pp.17-00362-17-00362, 2018 (Released:2018-01-25)

参考文献数

12

被引用文献数

1

---

In this paper, we discuss a modeling method and an altitude control system for a drone type UAV using the image information from the forward camera of the UAV. The model for the UAV dynamics is constructed based on the motion equation and the unknown velocity control logic which was made the internal organs in the drone system, and the parameters of the model are obtained by some experiments of the velocity constant control. The transfer function are expressed the 2 dimensional state space equation, and the optimal control method applied to the system include some limitation of the velocity control logic. This optimal control logic is realized as a PID control system. The P gain range of the PID controller is determined by the parameter of performance index of optimal control logic and the system keep optimal control feature in the range. By the experimental results, we confirmed that this system is stable and efficient.

著者

古巣 克也 尼子 龍幸 中川 稔章 浜辺 勉 青木 典久

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:18848338)

巻号頁・発行日

vol.79, no.801, pp.573-581, 2013 (Released:2013-05-25)

参考文献数

12

被引用文献数

2 8

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Recently, high strength steel material is used increasingly for plates which constitute the frame structures of vehicles. Since these plates become thinner, the buckling on the plates has been recognized as an important issue for automotive industries. In this paper, the expression is derived to obtain simply the shear stress on plates at torsional buckling for the box beams which represent the frame structure. Assuming the deflection shape of the buckled plate simply supported on all sides and the right angle at four corners, the precise expression is derived based on the energy method. However, this expression is complicated and hard to use easily. Therefore, the approximate expression is proposed by the knowledge from the aforementioned derivation. The accuracy of that expression is investigated as compared with the results acquired in the buckling eigenvalue analysis by FEM. As the results, the difference of shear stress at torsional buckling is less than about 5% as for the aspect ratio of the cross section between 0.4 - 1.0.

著者

相良 誠

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.107, no.1024, pp.149-151, 2004-03-05 (Released:2017-06-21)

著者

武田 真和 渡辺 昌宏

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.858, pp.17-00415-17-00415, 2018 (Released:2018-02-25)

参考文献数

16

被引用文献数

3

---

This paper presents experiments and an analysis of the self-excited vibration of a plate supported by air pressure. In the analysis, the unsteady fluid force acting on the plate is calculated based on the basic equation of a two-dimensional gap flow between the plate and a chamber surface. The basic equation considers the effect of air compressibility in the chamber. The characteristic equation of the system is derived from the plate motion coupled with the unsteady fluid force acting on the plate. The instability condition and vibration frequency are predicted through the root locus of the system with changing air flow rate supplied to the chamber. The experiment consists of a plate supported by the air pressure supplied from a slit on the upper surface of the chamber, where the vibration characteristics are examined. The influence of the slit width and chamber volume on the instability condition of the self-excited vibration is clarified comparing the analytical result with experiments. Moreover, the local work done by the unsteady fluid force acting on the plate (bottom surface) is shown in this paper, and the instability mechanism is discussed. Lastly, the influence of slit width on the unsteady fluid force is addressed by the block diagram showing the phase relationship of pressure fluctuation and plate displacement.

著者

藤田 貴行 塚本 哲 多田 茂

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.780, pp.3017-3024, 2011 (Released:2011-08-25)

参考文献数

35

被引用文献数

2

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1/f noises, the power spectrum density (PSD) of signals inversely proportional to the frequency, have been observed in various types of physical and physiological systems; e.g. current and heart beat. 1/f noise is suggested to be generated by superimposing stochastic processes. Among stochastic processes, autoregressive process is suitable for analyzing physical and physiological systems in that the autoregressive process is time-discrete. A time-discrete model is suitable for analyzing those systems because those systems are observed in time-discrete manner as well. However, it is obscure whether 1/f noises are generated by superimposing those autoregressive processes. In this study, first order autoregressive (AR(1)) processes were superimposed with varied the process parameter and a driving noise. As a result, PSD of superimposed time sequences was inversely proportion to the frequency when the process parameter and a driving noise were a uniformly distribution and white noises, respectively. This result suggests that 1/f noises could be generated from the superimposing AR(1) processes when the process parameter is distributed uniformly.

著者

和栗 明

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.83, no.738, pp.612-613, 1980-05-05 (Released:2017-06-21)

著者

河村 隆 野内 知樹 降旗 克行 栗林 直樹 青柳 匡尚 中﨑 滉平 北橋 尚浩 鈴木 智 飯塚 浩二郎

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 2016 (ISSN:24329509)

巻号頁・発行日

pp.C-20, 2016 (Released:2017-06-19)

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Curling is one of the winter sports called chess on ice. Athletes are required high level skill and smart strategy. This paper deals with curling phenomenon of rotation stone on the ice.To Understand this phenomenon, polypropylene and Teflon sheet makes low friction environment, and curling stone experiment was carried out. Then curling stone phenomenon was reproduced on force plate instead of ice.

著者

小原 伸哉 伊藤 優児 岡田 昌樹

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00266-17-00266, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

---

To level the fluctuations in electric power sourced from renewable energy, the transmission network can be spread over a wide area, but this is expected to dramatically increase the renewable energy rate. Therefore, this paper proposes an algorithm that analyzes the maximum amount of renewable energy in the network, and hence optimizes the type of electric power source connected to the transmission network, and the arrangement and capacity of each power source. The proposed algorithm is based on a genetic algorithm, which effectively processes many nonlinear variables concurrently. Accounting for the power interchange in the transmission network and the energy storage in electric heat pumps and heat storage tanks, the objective function plans the arrangement of the electric power sources that maximizes the economic efficiency of the system. The developed algorithm is applied to a renewable-energy network in Hokkaido, Japan. In this area, the introductory rate of renewable energy was 39.5% of the total electricity production. Moreover, the cost of a distributed power-supply network was 9.99 × 1010 USD. The proposed system is equivalent to 1.88 years of Hokkaido's energy consumption.

著者

岡田 和也 佐藤 明 二村 宗男

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.83, no.856, pp.17-00378-17-00378, 2017 (Released:2017-12-25)

参考文献数

16

被引用文献数

1

---

We have investigated a regime change in the aggregate structures of a suspension composed of magnetic cubic particles in thermodynamic equilibrium, by means of Monte Carlo simulations. In concrete, we have addressed the dependence of the regime change on a variety of factors such as the magnetic field strength and the magnetic particle-particle interaction strength. The orientational distribution function and order parameters have been focused on for quantitatively discussing these characteristics. The main results obtained here are summarized as follows. If the magnetic interaction strength is sufficiently large for cluster formation, closely-packed clusters are formed under the combination and expansion of a cluster unit composed of 8 particles. A regime change in the internal structure of aggregates appears in a narrow range of the magnetic interaction strength, which is clearly exhibited by the order parameter employed here. A closely-packed configuration can be clearly characterized by the orientational distribution function; 8 high peaks appear in the orientational space in the case of the closely-packed structure. As the magnetic field is increased, the closely-packed clusters are collapsed and transformed into wall-like clusters along the magnetic field direction. This is because the magnetic moment of each particle has a strong tendency to incline in the magnetic field direction in the situation of a strong magnetic field.

著者

横山 真男 瀬田 陽平 矢川 元基

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.83, no.856, pp.17-00287-17-00287, 2017 (Released:2017-12-25)

参考文献数

15

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Based on experimental observation of liquid dripping, a method to prevent liquid adhesion at the wall of cup was proposed in this paper. When water or sauce etc. is poured from edge of a cup or a pot, the liquid adheres to the wall of cup, which often makes a table or clothes dirty. To clarify the above annoying problem, the flow dripping from the cup, whose edge was shaped to have various thin channels, was observed by using high speed camera. We found the water adhesion on cup's wall reduced when the channels were located at the outside of edge of the cup.

著者

天野 歩 阪口 基己 黒川 悠 岡嶋 芳史 井上 裕嗣

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.83, no.856, pp.17-00377-17-00377, 2017 (Released:2017-12-25)

参考文献数

28

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In order to investigate the fundamental process of residual stress development in thermal barrier coating during thermal spray, a model experiment was conducted using a paraffin wax. Melted paraffin wax was dropped onto a circular substrate of type 430 stainless steel, and strain and temperature were measured on the back surface of substrate. The model experiment revealed that tensile quenching strain was developed during solidification and adhesion process and it was increased with the number of droplets. Development of the quenching strain and failure of paraffin coating were significantly influenced by substrate temperature. The lower substrate temperature caused the larger quenching strain, and facilitated cracking, delamination and debonding of the coating. Findings in a series of the model experiments showed some similarities to actual phenomena during thermal spray, and will provide a helpful suggestion to optimize various process parameters in thermal spray.

著者

上 剛司 山田 浩之 小笠原 永久

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00261-17-00261, 2017 (Released:2017-12-25)

参考文献数

37

被引用文献数

1

---

Indentation tests are used to determine the local mechanical properties of materials. Previously, the indentation strain rate was correlated with the strain rate in uniaxial tests based on the hardness, which was the obtained load divided by the cross-sectional area. However, the hardness can be influenced by pile-up of material after indentation. The purpose of this study was to relate the indentation strain rate with the uniaxial strain rate through serration behavior. The material used in this study was 5082 aluminum alloy, whose main alloying elements are aluminum and magnesium, and which is known to exhibit serration at certain temperatures and strain rates. Quasi-static uniaxial tensile tests were performed at strain rates from 10-4 to 10-1 s-1 at room temperature. Micro-indentation using a Berkovich indenter was performed at constant loading rates from 0.7 to 350 mN/s. The loading curvature, which was defined as the load divided by the square of the displacement, was used instead of the hardness to avoid the pile-up effect. As a result, the serrated loading curvature in the indentation tests was obtained as the decreasing loading rate. The effective strain rate, which was defined as the derivative of the load with respect to time divided by two times the applied load, decreased with increasing displacement. The serrated loading curvature changed its behavior as the effective strain rate decreased. It behaved similarly to the serration observed in uniaxial tensile tests. It was found that the indentation strain rate is correlated with the strain rate in uniaxial tensile tests through the serration behavior.

著者

吉中 奎貴 中村 孝 髙久 和明 塩澤 大輝 中井 善一 上杉 健太朗

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.83, no.856, pp.17-00104-17-00104, 2017 (Released:2017-12-25)

参考文献数

23

被引用文献数

2

---

The initiation and growth of internal small fatigue cracks with around ten or several dozen μm in Ti-6Al-4V were nondestructively examined by using synchrotron radiation μCT at the large synchrotron radiation facility SPring-8. Lots of grain-sized internal cracks were observed roughly evenly in the observation volume in the specimen; in contrast, only one surface crack was detected. The initiation lives of the internal cracks were widely different for each crack and had no significant correlation with the crack initiation site nor the initial crack size. The internal cracks propagated microstructure-sensitively with several crack deflections, and the growth rates were very small, less than 10-10 m/cycle. The crack growth rates just after facet formations showed large variability and had no apparent relationship with the crack initiation life nor the initial crack size. This variability can likely be attributed to microstructural inhomogeneities around the crack initiation facets. The estimated facet formation rate indicated that most facets formed rapidly compared with the following internal crack growth rate.

著者

渡邉 麻友美 射手園 健斗 遠藤 央 菅原 雄介 岡本 淳 柿崎 隆夫

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

巻号頁・発行日

vol.2017, pp.2A2-L05, 2017

---

<p>In this study, focusing on the sustainability of the environment and health, it has proposed a mobility that human-powered. The proposed system is designed on the "Man-powered robotics", which realizes the intelligent operation by controlling the power to be transmitted to the output shaft in the robot system. Manpower to implement the safety control in mobility to the power source, it puts control to allow prolonged exercise. As a result , to health by increasing the chance of occupant movement. Moreover, by making human power to power, it becomes environmentally friendly mobility. In this paper, the mobility of control is discussed. Specifically, when mobility operates in one dimension, Simulate the torque around the pedal axis. This confirms the effectiveness of control.</p>

著者

林 晃生 中尾 陽一

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 (ISSN:21879761)

巻号頁・発行日

vol.83, no.856, pp.17-00268-17-00268, 2017 (Released:2017-12-25)

参考文献数

14

被引用文献数

1

---

Recently, the ultra-precision parts have become essential in many areas of advanced technology, including medical equipment, aircraft equipment, optical equipment and so on. These ultra-precision parts are required to have a high surface quality. Therefore, further precise machining and motion accuracy are required for the ultra-precision machine tools that machine these parts. Thus, the water-driven spindle, which is equipped with water hydrostatic bearings and a water-driven mechanism, was developed for ultra-precision machine tools. This spindle has higher stiffness than a spindle supported by aerostatic bearings. However, the heat generation due to fluid viscosity occurs at the bearings. If the temperature of each part in the spindle changes, undesirable deformation of the parts will occur. Deformation of the spindle during the machining process will then degrade the machining accuracy. In contrast, the water-driven spindle uses water as a lubricating fluid. Furthermore, water flow is supplied into the spindle in order to generate the driving power. Therefore, the water flow is an effective cooling medium for the water-driven spindle. Water cooling can be used to improve the thermal stability of the spindle because water has higher thermal conductivity and higher specific heat. In the present paper, the thermal stability of the water driven spindle is investigated experimentally. As a preliminary step, the changes in temperature of the water flow and the outer surface of the spindle are measured experimentally during spindle rotation at various rotational speeds. Furthermore, the influence of the power loss during spindle rotation on the temperature change of the water flow is investigated through calculations and experiments.

著者

寺井 久宣 浅尾 晃通 吉川 浩一 水垣 善夫

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.83, no.856, pp.17-00265-17-00265, 2017 (Released:2017-12-25)

参考文献数

11

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The ball end mill is used as a tool for cutting the metal mold and some complicated shape lake a screw. The demand for the precise machining of the ball end milling is increasing. The ball end milling has the unavoidable problem of machining error by the elastic deformation of tool because of its low rigidity. So this report is set up the new method of the high precision machining used by the tool orientation control. The machining area at the point of the surface generation is changed depend on the tool orientation of the ball end mill. The geometric mechanism is analyzed and the relationship between the machining area and the tool orientation is clarified. And the cutting force and the machining error are measured by the machining test that the tool orientation has been varied. As the result, it is verified that the machining error becomes large at the point, which the machining area is large. And the machining error estimation index has been proposed and calculated about three dimensional surface.