著者

佐藤 知広 久保田 敦斗 齋藤 賢一 藤 正督 高井 千加 瀬名 ハディ 宅間 正則 高橋 可昌

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.71, no.2, pp.167-174, 2022-02-15 (Released:2022-02-20)

参考文献数

14

被引用文献数

1

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The industrial manufacturing methods for ceramics are powder mixing, molding, and firing. Ceramics are fired at a higher temperature than metal sintering. For this reason, in the ceramics manufacturing process, a large amount of energy is consumed, and a large amount of carbon dioxide is also emitted, especially in the firing process. Therefore, attention is focused on the non-firing solidification process of ceramics. In this method, after the molding process, there is a solidification process using a solvent instead of firing. In order to realize this solidification process, a grinding process is required to increase the activation energy of the surface of the raw ceramics particle. Therefore, in this study, we set up a molecular dynamics model that simulated grinding and calculated the activation of the silica surface. The grinding of the material surface was modified by the cylindrical indenter of LAMMPS, the material surface was constantly activated by passing multiple indenters continuously instead of a single indenter. As a result, a clear increase in energy was observed. It was suggested that continuous energy input is more effective than local energy input to the surface when reproducing surface activity. Furthermore, activation of the internal structure was observed as in the experiment. Adding water molecules in the relaxation calculation on the activated surface, binding through and without water molecules was observed. It was clarified that there are hydrogen bonds and siloxane bonds in this bond.

著者

栗林 大樹 佐藤 知広 齋藤 賢一 宅間 正則 高橋 可昌

出版者

一般社団法人 粉体粉末冶金協会

雑誌

粉体および粉末冶金 (ISSN:05328799)

巻号頁・発行日

vol.68, no.8, pp.317-323, 2021-08-15 (Released:2021-08-15)

参考文献数

16

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In recent years, materials infomatics (MI), a technology that combines materials engineering and machine learning, has become popular and is used for discovering new materials. In this research, we aimed to verify whether MI can be applied to the problem of “development and maintenance of technology,” which is becoming more difficult due to the decrease in the number of engineers caused by the declining birthrate and aging population in Japan. We selected “discrimination of optical electron microscope images” as the verification target, and used Convolutional Neural Networks (CNNs) as the machine learning technology to discriminate between seven types of sintered metal objects under different sintering conditions, hoping for general applicability to the discrimination problem, and confirmed a discrimination accuracy of 98.5%. In addition, we verified the effectiveness of using pseudo-samples for the discrimination problem using Generative Adversarial Networks (GANs) in the hope of improving accuracy by increasing the number of samples, and confirmed the improvement of accuracy by adding pseudo-samples to the training data.

著者

北村 隆行 澄川 貴志 平方 寛之 高橋 可昌 嶋田 隆広

出版者

京都大学

雑誌

特別推進研究

巻号頁・発行日

2013

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single digit ナノスケール(1nm ~ 10nm)の応力特異場を有する材料に対するその場観察破壊実験方法を開発し、シリコン単結晶の実験より特異場寸法4nmであっても破壊靭性値は不変であることを明らかにした。また、第一原理解析と実験が一致することを示すとともに、応力特異場が2nm以下の場合に従来の破壊力学基準が破綻する(連続体破壊力学の適用下限)ことを明らかにした。

著者

岩田 郷志 宅間 正則 齋藤 賢一 松井 淳基 高橋 可昌 都築 勇人

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.80, no.818, pp.SMM0292-SMM0292, 2014 (Released:2014-10-25)

参考文献数

18

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A6061-T6 alloy has been used in the liner material of high-pressure hydrogen gas storage container that is mounted on a fuel cell vehicle. The degradation of the properties such as strength, toughness and hydrogen embrittlement resistance, etc., has been pointed out, because the grain structure of the mouthpiece part of the liner becomes coarse in the manufacturing process. The tensile and fatigue test for the specimens with different grain size were done, and the detected AE signals during the testing were analyzed. In the tensile test, the characteristics of the signals on dislocation motion, transgranular and intergranular fracture were extracted. In the fatigue test, it was shown that the possibility of which the damage is evaluated by the spectral analysis that utilizes the slope of an approximation straight line in the both logarithmic scale display of FFT analysis result. Then we proposed the amplitude ratio Rv that is the parameter which divided the maximum amplitude of signal for intergranular fracture by that of detected signal, and the correlation between the grain size and the Rv was recognized. These proposed information are able to be utilized in order to evaluate the damage of the container.