著者

檜木 正博

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2012, pp."W003003-1"-"W003003-3", 2012-09-09

著者

渡邉 大貴 藤本 修平 緒方 正幸 熊谷 一郎

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2015, pp."S0510104-1"-"S0510104-5", 2015-09-13

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Laboratory experiments on the flow visualization of the airless sprayer were conducted using shear thinning fluids (xanthan gum solutions) in order to improve the efficiency and the quality in the painting process for the ship hull. The behavior of liquid film instability and the droplet formation were strongly affected by the fluid rheology (concentration of xanthan gum solutions) and the spray pressure. In the atomization of 2.0 wt% xanthan gum solution, which is similar to the real paint in rheological property, the behavior of the spinnability was observed. We quantitatively examined the spatio-temporal variation of the liquid film collapsing, and extracted the dominant frequency components of the droplet formation by DFT analysis.

著者

佐藤 一永 橋田 俊之

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."J061023-1"-"J061023-2", 2013-09-08

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The influence of uniaxial compressive stress on the oxygen ion and mixed conductivity of Zr_<0.82>Y_<0.18>O_<1.91>, Ce_<0.9>Gd_<0.1>O_<1.95-δ>,Yba_2Cu_3O_<7-δ>,and La_2NiO_<4+δ> were investigated by using AC 4 probe method under controlled oxygen partial pressure condition. The applied compressive stress was ranged from 0 Mpa to 350 MPa for these specimens in air at 600℃. In order to clarify the reason for the phenomenon of conductivity change, the mixed conductivity of Ce_<0.9>Gd_<0.1>O_<1.95-δ> for the application of stresses were measured under reducing conditions. The experimental result revealed that as the application compressive stress increases, the carrier concentration remain steady, whereas the mobility decreases. The conductivity was decreased with increasing compressive strain, this trend agreed with that of the simulation results. Therefore, the decrease of mobility was considered to be the reason for the decline conductivity under compressive strain/stress conditions.

著者

山藤 勝彦 山本 建 橋本 真 新 誠一 澤田 賢治

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."J101012-1"-"J101012-5", 2013-09-08

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Judder is well known oscillation occurring in dry clutches. To maintain riding comfort and silence in dry clutches, a lot of studies of judder analysis and machine design suppressing judder have been done. This paper describes the design and implementation of a robust control technique as a judder suppression approach for clutch during shifting. We address the automatic transmission using dry clutches of which the μ-V characteristics show a complicated nonlinearity. Specifically, their friction coefficient varies non-linearly with respect to the rotational speed during shifting. In this paper, it is clarified that the non-linear μ-V characteristic can be expressed as frequency uncertainties and then the control system is constructed with H∞ control. To verify the validity of such the approach, the results of simulation and bench testing are presented. As a result, we see that the proposed approach allows us to achieve the shifting without judder. Furthermore, we show the three controller requirements by analyzing the robust controllers.

著者

西嶋 規世 遠藤 彰 山口 和幸

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."J101022-1"-"J101022-3", 2013-09-08

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Labyrinth seals have the potential to cause rotordynamic instability induced by the fluid force of seal flows. We conducted a computational fluid dynamics (CFD) study to investigate the rotordynamic characteristics of the shaft labyrinth seal of a steam turbine. The effects of different seal gap (0.42-0.85 mm) and seal length (47.6-357 mm) were systematically investigated. The predicted stiffness coefficients increased with increasing seal length as expected, but short seals (<100 mm) indicated stronger dependence on seal length. Stiffness coefficients of short seals also indicated strong dependence on seal gap, and increased inversely with decreasing gap, while stiffness coefficients of long seals depend less on seal gap.

著者

吉田 浩之 境野 恵理

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2014, pp."S1140105-1"-"S1140105-4", 2014-09-07

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With downsizing of automobile electrical components, the sliding conditions of gears and clutches have become more severe. As a response to this, PTFE powder is used in lubricating oils as an additive. However, the relationship between the properties of PTFE powder and the friction characteristics of lubricants containing PTFE powder has not been clarified yet. In this study, we measured the friction characteristics of a lubricant by varying the powder concentration and particle size on a pin-on-disk friction tester. As a result, the following two findings were obtained; 1. As the powder concentration increases, the coefficient of friction decreases. 2. At a high powder concentration, the lower the lubricating oil liquidity, the lower the coefficient of friction.

著者

田中 健輔 福富 純一郎 重光 亨 清水 大喜

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."J055022-1"-"J055022-5", 2013-09-08

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Small-sized axial fan is used as air cooler for electric equipments. But there is strong demand for higher power of fan according to the increase of quantity of heat from electric devices. Therefore, higher rotational speed design is necessary, however it causes the deterioration of efficiency and increases the noise. Contra-rotating axial fan is smaller than conventional axial fan under the same rotational speed, and is effective for lower rotational speed design under the same diameter. Then, contra-rotating rotors were proposed for the improvement of the performance of small-sized axial fans and the advantages of it on the point of view of the performance were confirmed. In the present paper, the performance curves and internal flow of the contra-rotating small-sized axial fan with 100mm diameter obtained by the experimental and numerical analysis results are shown and the pressure distribution and attack angle of rear rotor at the design flow rate are clarified. Furthermore, the influence of the blade row distance on the performance and internal flow condition is clarified and higher performance design of the contra-rotating small-sized axial fan are discussed.

著者

小木曽 望 上馬場 雄太 岡田 侑樹 坂本 啓

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2011, pp."J191013-1"-"J191013-5", 2011-09-11

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Design of a very precise space structural system requires an accurate estimation of uncertainties on structural and environmental parameters. For the purpose, high accurate estimations of uncertainties of the structural parameters and the effect of the paremeter uncertainties on the structural response uncertainty are required. Then, the robust design optimization based on the accurate estaimation is required. This study focuses on the former part, a high accurate estimation of the uncertainties. The applicability of a bootstrap method known as a nonparametric technique is investigated to estimate the confidence intervals of the uncertain parameters related to vibration responses of simple structures. The target structure is a cantileverd bow-shaped structure composed of beam and tether that is a breadboard model of a lightweight space reflector. The confidence intervals identified from several numbers of vibration tests is compared by the nonlinear finite-element analysis.

著者

大場 恭子 吉澤 厚文 北村 正晴

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2015, pp."G1700106-1"-"G1700106-5", 2015-09-13

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The Fukushima nuclear plant accident has been examined aiming at clarifying the factors influencing responding which is one of the four cornerstones of resilience engineering. Among the causal factors of responding, such as attitude, skill, health and environment, particular attention has been paid on the role of attitude. In addition, the case of Tokai Dai-ni nuclear plant, which was the success case despite tsunami attack, and the case of Fukushima Dai-ichi nuclear plant have been examined focusing on preparatory actions taken prior to the tsunami attack. Through the camparative exainations, attitudes of several kinds have been identified as key factors contributing to enhance organizational resilience. Moreover, the importance of safety-II concept proposed in conjunction with the methodology of resilience engineering has been clearly exemplified. As a whole, it can be concluded that the methodology of resilience engineering and the concept of safety-II are quite effective when utilized with the structured model.

著者

アルマハドウリ アディル 江目 宏樹 岡島 淳之介 小宮 敦樹 円山 重直

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2013, pp."G061052-1"-"G061052-5", 2013-09-08

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In the present study, a theoretical non-gray rigorous model was established to study the radiative heat transfer through greenhouse covering materials by using Radiative Element Method by Ray Emission Model (REM2). This model was applied to find the difference in thermal performances between silica glass, polyvinylchloride (PVC) and low density polyethylene (LDPE) covering materials. Using the advantage of the previously predicted spectral radiative properties of these materials, accurate estimations of greenhouse temperatures were achieved. In addition, an outdoor experiment was conducted to measure the thermal performances of three rectangular enclosures covered by the mentioned claddings. Enclosures inside, floor and cover temperatures calculated using the rigorous model showed a satisfactory correlation with the experimental measurements

著者

延明 雅通 田中 慎也 杉本 旭

出版者

一般社団法人日本機械学会

雑誌

年次大会 : Mechanical Engineering Congress, Japan

巻号頁・発行日

vol.2012, pp."S171014-1"-"S171014-4", 2012-09-09

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It was widely known by the Fukushima nuclear power plant disaster at the nuclear power plant that it may be a fatal accident. Since there is possibility of fatal damage, even if it will be unexpected accident, the nuclear power plant disaster must avoid. It consider that in order to correspond to an unexpected accident, the stop based on the definite theory of safety, especially a time concept Moreover, it consider that the safety of a nuclear power plant and the active safety which attains a high operating ratio simultaneously.