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2020/9 Vol.123

表紙の説明:これは、フライス盤のテーブルに取り付けて使用する割出し台の割出し板部分である。ハンドルを回して穴へピンをさし込んで直接割り出す方法と、送り機構から駆動させる方法がある。これを用いて、円筒工作物の外周上に等分割の溝をフライス加工したり、インボリュートカッタを取付けて歯切り加工したりできる。
[日本工業大学工業技術博物館]

表紙写真 北原 一宏

バックナンバー

論文アクセスランキング

日本機械学会学術誌(英文) 年間アクセス数トップ10

(2019年4月~2020年3月の期間で集計) *順位の変動は2019年1月~2019年12月の期間との比較


Large eddy simulation with modeled wall-stress: recent progress and future directions

Johan LARSSON, Soshi KAWAI, Julien BODART, Ivan BERMEJO-MORENO

Mechanical Engineering Reviews(2016) DOI:10.1299/mer.15-00418
The paper provides a brief introduction to the near-wall problem of LES and how it can be solved through modeling of the near-wall turbulence. The distinctions and key differences between different approaches are emphasized, both in terms of fidelity (LES, wall-modeled LES, and DES) and in terms of different wall-modeled LES approaches (hybrid LES/RANS and wall-stress-models). The focus is on approaches that model the wall-stress directly, i.e., methods for which the LES equations are formally solved all the way down to the wall. Progress over the last decade is reviewed, and the most important and promising directions for future research are discussed.

Investigation of the mechanism of the indentation size effect for titanium

Shota HASUNUMA, Hirohisa MIYAZAKI, Takeshi OGAWA

Mechanical Engineering Journal (2019) DOI:10.1299/mej.18-00545
In this study, we investigated the mechanism of the indentation size effect for Ti, whose crystal structure is hexagonal close-packed. Indentation tests were performed for two types of single-crystal Ti with different crystal orientations: (0001) and (1120). Indentation tests were also performed with different indenter directions. The hardness depends on the crystal orientation and indenter direction because Ti has large anisotropy. The shape of the impression also changes with the crystal orientation and indenter direction. The hardness increases with decreasing penetration depth for the (0001) and (1120) orientations, so the indentation size effect occurs. For the (0001) orientation, a sudden rapid increase in displacement occurs during indentation tests owing to twinning. This sudden rapid increase in displacement causes a rapid decrease in the hardness. Electron backscatter diffraction was performed around the impressions to measure the geometrically necessary (GN) dislocation density. The GN dislocation density increases with decreasing penetration depth for the (0001) and (1120) orientations. This trend corresponds to strain gradient theory. The reason for the indentation size effect in Ti is the increase in the GN dislocation density. For the (0001) orientation, the indentation size effect also can be attributed to twinning. Considering both our previous study and this study, the experimental results correspond to strain gradient theory in many cases.

Running position matching for the monitoring bogie and temporal subtraction analysis of derailment coefficient

Yosuke ICHIYANAGI, Yohei MICHITSUJI, Akira MATSUMOTO, Yasuhiro SATO, Hiroyuki OHNO, Seigo OGATA, Masuhisa TANIMOTO, Atsushi IWAMOTO, Tomoki FUKUSHIMA, Takuji NAKAI

Mechanical Engineering Journal (2019) DOI:10.1299/mej.18-00426
The derailment coefficient, which is calculated based on the wheel-rail contact forces, indicates the running safety of a railway vehicle with respect to flange climb derailment. The value of the derailment coefficient changes constantly due to numerous factors associated with the vehicle and track conditions while the vehicle runs on a service line. Therefore, it is desirable to monitor the state of the wheel/rail contact in order to ensure the running safety. Recently, a new monitoring bogie, which can measure the derailment coefficient during commercial operations, has been developed and introduced into some service lines. Large-scale data have been collected by this monitoring bogie. In this paper, the temporal subtraction analysis is carried out for preparing appropriate plan for reducing the derailment coefficient based on these data. In the analysis, the vehicle running position is important for accurate calculation of the difference between two waveforms. However, the vehicle running position contains errors because of the accumulated error of integral calculation of the vehicle velocity. The present paper proposes a method which modifies the running position along track so that the two waveforms are well matched. The proposed method is based on DP matching, and the waveforms of the track irregularity of twist estimated by the monitoring bogie are used in the method. After DP matching, an example of temporal subtraction analysis of the derailment coefficient between two periods is performed. Finally, by using the long-term measurements acquired by the monitoring bogie, the monthly variation of the derailment coefficient for a certain spot on the track is shown as a practical example.

4位

[↑]

Development of flow-accelerated corrosion prediction method (2) Modeling and validation with thinning rate profile data

Kimitoshi YONEDA, Kazutoshi FUJIWARA, Ryo MORITA, Fumio INADA
Mechanical Engineering Journal (2018) DOI:10.1299/mej.17-00415

5位

[→]

Development of tunnel compression wave generator with multiple small solenoid valves

Tokuzo MIYACHI, Takakage ARAI, Shoji SAKAUE, Koji TAKASHIMA, Daiki TANIKAWA, Takuya YAGISHITA, Kento NAKATANI
Mechanical Engineering Journal (2019) DOI:10.1299/mej.18-00478

6位

[↓]

Prospect and Recent Research & Development for Civil Use Autonomous Unmanned Aircraft as UAV and MAV

Kenzo NONAMI
Journal of System Design and Dynamics (2007) DOI:10.1299/jsdd.1.120

7位

[NEW]

Track geometry estimation of a conventional railway from car-body acceleration measurement

Mai ODASHIMA, Shohei AZAMI, Yasukumi NAGANUMA, Hirotaka MORI, Hitoshi TSUNASHIMA
Mechanical Engineering Journal (2017) DOI:10.1299/mej.16-00498

8位

[NEW]

Strain distribution in the anterior cruciate ligament in response to anterior drawer force to the knee

Satoshi YAMAKAWA, Richard E. DEBSKI, Hiromichi FUJIE
Journal of Biomechanical Science and Engineering (2017) DOI:10.1299/jbse.16-00582

9位

[NEW]

Elastic buckling of cylindrical shell under pressure load evaluated on surface

Takeki YAMAMOTO, Takahiro YAMADA
Mechanical Engineering Journal (2019) DOI:10.1299/mej.19-00113

10位

[↓]

Estimation method of interfacial stiffness of bolted joint in multi-material structure by inverse analysis

Yoshinao KISHIMOTO, Yukiyoshi KOBAYASHI, Toshihisa OHTSUKA, Akira MATSUMOTO, Motoi NIIZUMA
Mechanical Engineering Journal (2019) DOI:10.1299/mej.18-00471

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