著者

甲嶋 秀平 梶井 憲弘 細井 厚志 川田 宏之

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.85, no.871, pp.18-00435, 2019 (Released:2019-03-25)

参考文献数

25

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Carbon fiber reinforced plastics (CFRPs) are widely used as components of marine structures. Thus, it is important to understand the degradation of the mechanical properties and its mechanism under seawater immersion. The object of this study is the influence of seawater immersion on the mechanical properties of plain woven CFRP laminates. Static tensile test and tensile fatigue test were carried out on the CFRP immersed different time under seawater for 300, 2500 and 5400 hours. The mechanical properties immersed for 300 hours was almost the same value compared with those of no immersion. However, the tensile strength immersed for both 2500 and 5400 hours reduced by 22.5% compared with that of no immersion. Then, from the fatigue results, in the low-cycle fatigue region, the fatigue strengths decreased as immersion time was longer, on the other hand, in the high-cycle fatigue region, the fatigue strength did not change significantly regardless of immersion time. As a result, the inclination of S-N curves became gentle as immersion time was longer. From observation of fracture surfaces by scanning electron microscopy (SEM), it was shown that the fiber/matrix interface deteriorated remarkably after seawater immersion. Moreover, the difference of damage growth behaviors due to immersed in seawater under fatigue loading was investigated using soft X-ray photography. On specimen immersed in seawater, the accumulation of damage expanded more widely due to interface degradation compared with that of no immersion. Considering these results, it was suggested that the static tensile strength depended on load transmission efficiency between fiber and matrix, on the other hand, the fatigue strength in high cycle fatigue region depended on the strength of fiber along 0° that had small influences by seawater immersion.

著者

清水 誠二

出版者

一般社団法人 日本機械学会

雑誌

公開研究会・講演会技術と社会の関連を巡って : 技術史から経営戦略まで : 講演論文集 2016 (ISSN:24329487)

巻号頁・発行日

pp.111, 2016 (Released:2017-06-19)

著者

村井 亮介

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.116, no.1138, pp.624-625, 2013-09-05 (Released:2017-06-21)

被引用文献数

3 2

著者

吉住 文太 近藤 靖裕 諸井 隆宏 玉野 真司 森西 洋平

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.806, pp.2003-2018, 2013 (Released:2013-10-25)

参考文献数

3

被引用文献数

2 2

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The opening delay of a discharge reed valve for compressors caused by the oil film in the clearance between the reed and the valve seat is investigated. The developed simulation method which couples the reed deformation, the gas flow and the oil film flow is applied to simulate delay times on two types of seats with different contact areas. Three models for cavitaion in the oil film are tested; no-cavitation model, the static cavitation model (Reynolds' condition), and the dynamic cavitaton model in which the bubble expansion is directly simulated. The calculaion through the dynamic cavitation model reproduces well experimental results with regard to the delay time and oil film behaviors of cavitation and blow-by (oil film rupture). The result also shows that the growth of cavitation bubbles occupies the change in the oil film volume and prevents the oil film pressure from falling. The rupture mechanism based on the calculation results is that the increase of the oil film thickness directly causes the oil film pressure recovery leading to the blow-by flow, and both cavitation and the smaller contact area promote the growth of the oil film thickness.

著者

山中 俊治

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.112, no.1093, pp.960-961, 2009-12-05 (Released:2017-06-21)

参考文献数

3

著者

伊藤 景視 上野 哲

出版者

一般社団法人 日本機械学会

雑誌

「運動と振動の制御」シンポジウム講演論文集 2015.14 (ISSN:24243000)

巻号頁・発行日

pp.277-280, 2015-06-22 (Released:2017-06-19)

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This study expresses a novel active vibration control method for a house structure by using magnetic levitation. The magnetic levitation system is easy to install to the ceiling because there is no need to use linear guides or bearings. In this study, a magnetic levitation device is attached to the iron plate fixed firmly to ceiling of the structure and it will levitate when a vibration occurs. The total mass of structure will be decreased while levitating, resulting in the change of its natural frequency. Moreover, an efficient vibration control method is examined. Finally the results of experiments are shown to confirm its feasibility.

著者

新井 隆景 橋本 弘之

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.51, no.465, pp.1624-1630, 1985-05-25 (Released:2008-03-28)

参考文献数

7

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Helical surface instability of a cylindrical liquid jet in a cocurrent uniform gas stream were investigated theoretically and experimentally. The results of the linear instability theory showed that a nonaxisymmetric wave disturbance could grow enough for a large relative velocity between the liquid jet and the gas stream. When the relative velocity became larger than a specified value, the shape of the liquid jet changed from "axisymmetric mode". The helical disturbance on the liquid surface over the downward liquid column and broke up into droplets. For the frequency of the helical disturbance, the theoretical results agreed well with the experimental results. It was also found that the relation of the helical disturbances to the fluid Flow conditions.

著者

二ツ寺 直樹

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 2013.22 (ISSN:24243175)

巻号頁・発行日

pp.35-46, 2013-12-09 (Released:2017-06-19)

著者

小金丸 高志 黒河 周平 林 照剛 松川 洋二 後藤 愛実

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 2021.74 (ISSN:24242780)

巻号頁・発行日

pp.C21, 2021 (Released:2021-09-25)

著者

田部井 勝稲 白井 紘行

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.55, no.512, pp.1030-1034, 1989-04-25 (Released:2008-03-28)

参考文献数

8

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A numerical method is presented for inverting the moire data which represent integral light deflection to internal temperature and /or density distributions. The method is applicable to both symmetrical and asymmetrical flow field. The inverting method is constructed on the basis of the Maldonado-Olsen series representation which was developed for the inversion of an integral intensity fields. The validity and accuracy of the present method have been demonstrated by using a mathematical model with a density function of a truncated pyramid type.

著者

三村 泰成 吉村 忍 廣安 知之 三木 光範

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.69, no.683, pp.1066-1073, 2003-07-25 (Released:2008-02-21)

参考文献数

15

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This paper presents a new efficient real-coded genetic algorithms for constrained optimization. In general, it is efficient to use the gradient methods for the constrained optimization. However, because actual design problems often include extremely nonlinear or discontinuous characters, the gradient methods do not necessarily work well. Therefore, the present authors developed the "Center Neighborhood Crossover (CNX)" for real-coded genetic algorithms and applied to truss structure optimization. But, GAs have some fatal problems in handling the constraints. In the constrained optimization using GAs, designers have to translate the constrained problem to a basic unconstrained problem by using some methods such as the penalty function methods. It is, however, difficult to decide appropriate penalty parameters. In the present study, we developed "Real-coded Genetic Algorithms with Active Constraints (RGAAC)" In RGAAC, the points outside feasible area is pulled back to active constraints by the gradient method. The present method enables an efficient search.

著者

橋村 真治 山田 直樹 戸田 均

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.791, pp.1013-1022, 2012 (Released:2012-07-25)

参考文献数

10

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In this study, influence of nut configuration on fatigue characteristic of bolt/nut assembly under transverse vibration has been investigated. In the experiments, the apparent fatigue limits were investigated for two bolt/nut assemblies tightened with a flange nut and a tapered nut. The results showed that the apparent fatigue limit of the bolt/nut assembly tightened with the tapered nut was higher than that of the flange nut. Its causes were revealed by FE Analyses. As the result, it could be seen that a difference of nut inclinations when the assembly received the transverse load caused the difference of fatigue limits. It was also seen that the nominal stresses at root of the first thread were different even if the same transverse load was applied to the bolt/nut assembly.

著者

宗宮 詮 沢田 耕司 国尾 武

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.51, no.465, pp.1448-1452, 1985-05-25 (Released:2008-02-21)

参考文献数

11

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In this paper, the fatigue fracture process of FRP (SMC) was studied with a special attention to the variation of the stiffness ratio K which takes place during cyclic loading. Experimental results showed that the fatigue fracture process might be devided into the three characteristic stages, that is, (1) First stage (N=1∼N1) in which K dose not vary irrespective of cyclic loading, (2) Second stage in which the decreasing rate of the stiffness ratio defined by d(K)/d(logN) is constant, and (3) Final stage where the rapid decrease of the stiffness ratio at KIII leads to the final fatigue fracture. Furthermore, examination of scatters in experimental data at each stages by aid of probability plots showed that their distributions are the logarithmic normal ones. Also, it was found that the fatigue strength of SMC might be given by three characteristic parameters of N1, d(K)/d(logN) and KIII.

著者

樫原 輝 山口 友之

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 2019 (ISSN:24243124)

巻号頁・発行日

pp.2A2-N08, 2019 (Released:2019-12-25)

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Subjective palatability is related to human’s mental condition. According to Ministry of Health, Labour and Welfare JAPAN, unusual feeling palatability is one of depression signs. Additionally psychogenic taste disorder is occurred by stress. Subjective palatability sensing is expected to make human realize own mental health condition at objectively. However, it is difficult for us to measure subjective palatability because it has differences among individuals and many factors. We try to elucidate the relation between subjective palatability and facial biological information in order to consider subjective palatability sensing method. We found 2 relation from our experiment by using taste stimulations for 4 subjects. 1st is between vertical EOG variance and intensity of subjective palatability. 2nd is iEMG(integrated electromyogram) and tasteless or tasty. We implement subjective palatability calculation program from them. The result of it using measurement data in this study experiment shows the possibility of subjective palatability sensing.

著者

栗田 健 若林 雄介 山田 晴夫 堀内 雅彦

出版者

一般社団法人 日本機械学会

雑誌

環境工学総合シンポジウム講演論文集 2007.17 (ISSN:24242969)

巻号頁・発行日

pp.54-57, 2007-07-18 (Released:2017-06-19)

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It becomes more important to reduce the noise generated from Shinkansen train for further speed-up of Shinkansen. We developed the high-speed test train "FASTECH360" that has new equipment such as low-noise pantographs, "multi-segment slider", pantograph noise insulation plates and sound-absorbing panels for the noise from the lower area of car bodies. We investigated the noise distribution of "FASTECH360" by using a spiral microphone array, and we have taken countermeasures for the noise sources of "FASTECH360" based on the primary results of high-speed tests. Currently, the results show that the noise level of "FASTECH360" at the speed of 330km/h is approximately equal to that of the present commercial train at the speed of 275km/h (at a distance of 25m from the track).

著者

山崎 貴史 松岡 常吉 横山 博史 中村 祐二

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.86, no.889, pp.20-00210, 2020 (Released:2020-09-25)

参考文献数

25

被引用文献数

1 1

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The effects of the traveling sound wave generated by the speaker on diffusion flame were investigated experimentally. The sound frequency was varied from 50 to 1000 Hz using two sizes of loudspeakers, whose peak frequency showing the maximum sound pressure amplitude is nearly identical. A spirit lamp was used as the reference (diffusion) flame. Having irradiation of sound, the flame was inclined and stretched toward the traveling direction under specific range of the exposed frequencies and importantly, the effective range of the frequency was found to be quite different in two speakers used in this study. Precisely speaking, the deformed flame length reached its maximum value under the condition of 200 to 400 Hz for small speaker and 50 to 200 Hz for large speaker, respectively. In addition, the velocity distribution around the speaker was measured to reveal that the variation of flame length with respect to frequency, and it was found that the response against the applied frequency was rather close to that of flow velocity, not that of the acoustic pressure amplitude. Further investigation of flow field nearby the speaker clearly showed that the pump-like flow acceleration was induced by the periodic motion of the membrane of the speaker. From the above results obtained, it was confirmed that the effect of acoustic sound on the flame shall be come not only from pure acoustic wave feature but also from the factors depending on the hardware. Without the eliminating the latter effect, nature of acoustic-flame interaction behavior by using acoustic characters (e.g., frequency or acoustic pressure) is not readily available.

著者

小林 義光 浦崎 新八郎 三谷 祐一朗

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 2017 (ISSN:24243124)

巻号頁・発行日

pp.2P2-J11, 2017 (Released:2017-11-25)

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This paper describes miniaturization of electromagnetic levitation equipment with a PLC (Programmable Logic Controller). In order to learn advanced control theory with PLC, we constructed electromagnetic levitation equipment with a PLC. However it is necessary to use a small electromagnet and measure a position of a floating object without a position sensor in order to realize electromagnetic levitation conveyance system as small educational tool. Therefore we tried to find a condition of miniaturization of the equipment. The feedback controller model is designed by the linear control theory and implemented into PLC. As results, we confirmed that it is possible realize stable levitation by using a small electromagnet of low resistance value and a hall element instead of the position sensor.

著者

水口 博貴 長山 暁子 鶴田 隆治

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B編 (ISSN:18848346)

巻号頁・発行日

vol.77, no.781, pp.1826-1833, 2011 (Released:2011-09-25)

参考文献数

20

被引用文献数

1 2

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A simple theoretical expression for the evaporation/condensation coefficient in equilibrium has been proposed by Nagayama and Tsuruta based on the transition state theory and molecular dynamics simulations in 2003. It is not clear, however, whether this approach can be applied to complex molecules such as n-dodecane with long chain structures. In this study, molecular dynamics (MD) simulations have been performed to investigate the evaporation/condensation coefficients of n-dodecane in equilibrium systems. It is found that the evaporation coefficient of n-dodecane primarily depends on the translational energy and the surface temperature similar to simple molecules like argon and water, while the molecular orientation of long chain n-dodecane has less effect. Also, the MD data of n-dodecane agree well with the theoretical expression based on the transition state theory. We conclude that the evaporation coefficient can be predicted by the translational length ratio of liquid to vapor in general even for the long-chain molecules.

著者

石山 四郎

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.90, no.823, pp.670-674, 1987-06-05 (Released:2017-06-21)

著者

白木 直樹 加藤 洋子 安井 義隆 金子 貴志 大石 亨一

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 2010.19 (ISSN:24243175)

巻号頁・発行日

pp.229-232, 2010-12-01 (Released:2017-06-19)

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East Japan Railway Company (JR East) developed the hybrid system with the diesel engine and the lithium-ion battery, and began operational service of the world' s first hybrid diesel railcar Ki-Ha E200 in July 2007. This hybrid system could decrease the negative environmental impact of the diesel railcar. The rechargeable lithium-ion battery is selected for the storage battery because of high power and energy density. The deterioration investigation of the storage battery was executed in September 2009 and it is suggested the longevity might be extended for several years from this investigation.