著者

新井 和吉 高橋 秀明 浦澤 俊介 長谷川 直

出版者

一般社団法人 日本航空宇宙学会

雑誌

航空宇宙技術 (ISSN:18840477)

巻号頁・発行日

vol.11, pp.117-122, 2012 (Released:2012-10-10)

参考文献数

23

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A space debris shield for use with spacecraft and satellites was designed. A space debris shield is required to have high defense performance and be lightweight. In this paper, the pressurized wall in the shield composition was made into a double wall structure, and we considered inserting a liquid layer into the shield between these walls. First, the numerical analysis conditions of aluminum alloys of shield composition materials were established from reverse analysis using the ballistic limit equation of a Whipple shield. Using the scaled-down liquid shield, the liquid layer thickness was investigated by comparing the numerical analysis and impact tests that used a two-stage light gas gun. Next, the ballistic limit curve of a real-size liquid shield was examined using the numerical analysis. From these results, it was found that the liquid layer in the debris shield substantially slowed the velocity of incoming debris fragments.

著者

柄澤 秀親 柴﨑 広樹 糸日谷 剛 山下 慎一郎 新井 和吉

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.70, no.12, pp.896-903, 2021-12-15 (Released:2021-12-20)

参考文献数

15

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Sand erosion is a phenomenon in which the collision of solid particles erodes a material surface. The rate of sand erosion is higher in carbon fiber reinforced plastics (CFRP) than in metallic materials. Therefore, CFRP requires a light and protective coating material. Herein, to improve the erosion resistance of CFRP, five polyurethane coated CFRPs with different glass transition temperatures were investigated at elevated temperatures, and a prediction formula of the erosion rate at the elevated temperatures was established. Furthermore, computational fluid dynamics was used to predict the surface temperature and erosion rate of fan exit guide vane (FEGV) when polyurethane coating was applied, and the coating thickness for FEGV in the erosion environment was estimated based on these predictions.

著者

中阪 航平 柄澤 秀親 國島 大 新井 和吉

出版者

学校法人 法政大学情報メディア教育研究センター

雑誌

法政大学情報メディア教育研究センター研究報告 (ISSN:18827594)

巻号頁・発行日

vol.36, pp.54-57, 2021-07-08 (Released:2021-07-22)

参考文献数

6

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In this study, in order to investigate the material physical properties that affect the delamination of CFRP, impact analysis was performed by changing four types of physical properties. The tensile strength, interlayer shear strength, and Mode I interlayer fracture toughness and Mode II interlayer fracture toughness were used as four kinds of material physical properties.

著者

柄澤 秀親 篠山 英恵 石橋 之宏 酒井 哲也 新井 和吉

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.87, no.902, pp.21-00145, 2021 (Released:2021-10-25)

参考文献数

13

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The performance of a table tennis racket is often stipulated using an unique standard for the manufacturer. However, the performance criteria for restitution characteristics still have been unclear due to lack of qualitative evaluation by each manufacturer. For metal baseball bats, a formula that can easily estimate the coefficient of restitution (COR) for the bat has been proposed. Similarly, it is important to establish a method that can control the COR at the design stage for table tennis rackets. In this study, first, to understand the restitution characteristics of the table tennis ball used in the official game, an impact test was conducted on a pseudo-rigid wall at low to high velocity. Then, for 15 types of rackets, the COR of the racket body (with and without rubber) was measured. Additionally, the natural frequency and flexural rigidity of the racket body without rubber were measured. Furthermore, these experimental data revealed relationships between the COR and both of the impact velocity and natural frequency of the racket. A formula for the COR was derived similar to that for a baseball bat, and developed by considering the flexural rigidity. The effect of rubber on the COR was also investigated. Consequently, the effects of ball’s impact velocity, racket’s natural frequency and racket’s flexural rigidity on the COR of the racket were clarified. From these results, an equation that can estimate and control the COR of the racket at the design stage was developed.

著者

渡邉 敬人 藤原 聖司 後藤 裕太 岩原 光男 長松 昭男 新井 和吉 寺西 幸弘 長尾 裕史

出版者

日本機械学会

雑誌

ジョイント・シンポジウム講演論文集:スポーツ工学シンポジウム:シンポジウム:ヒューマン・ダイナミックス

巻号頁・発行日

vol.2006, pp.104-109, 2006

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Recently, baseball bats that have kinds of characters have been marketed due to advances in the materials and structure of modern baseball bats. One of remarkable point is a sweet spot in bats. But a sweet spot is sensuous and its point is laxness. So the reason why a sweet spot is approved is researched in this study. First of all, the first node, the second node and center of impact were measured. Next, the ball was made to collide with them and the repulsion coefficients were measured, and compared.