山口 栄輝 (ヤマグチ エイキ)

YAMAGUCHI Eiki

写真a

職名

教授

研究室住所

福岡県北九州市戸畑区仙水町1-1

研究分野・キーワード

鋼橋,構造解析,維持管理,設計

出身大学 【 表示 / 非表示

  • 1981年03月   東京大学   工学部   土木工学   卒業   日本国

取得学位 【 表示 / 非表示

  • パデュー大学 -  工学博士(Ph.D.)  1987年12月

学内職務経歴 【 表示 / 非表示

  • 2016年04月
    -
    2018年03月

    九州工業大学   副学長  

  • 2008年04月
    -
    継続中

    九州工業大学   大学院工学研究院   建設社会工学研究系   教授  

学外略歴 【 表示 / 非表示

  • 1992年04月
    -
    1994年03月

    東京大学   助教授   日本国

  • 1990年07月
    -
    1992年03月

    東京大学   講師   日本国

  • 1987年04月
    -
    1990年06月

    九州大学   助手   日本国

専門分野(科研費分類) 【 表示 / 非表示

  • 構造工学・地震工学・維持管理工学

 

論文 【 表示 / 非表示

  • Effect of rubber insertion on impact behavior of multilayer steel fiber reinforced concrete bulletproof panel

    Maho B., Sukontasukkul P., Jamnam S., Yamaguchi E., Fujikake K., Banthia N.

    Construction and Building Materials    216   476 - 484   2019年08月  [査読有り]

     概要を見る

    © 2019 Elsevier Ltd In this study, the effect of para rubber insertion sheet on impact behavior of multilayer bulletproof panel made of steel fiber reinforced concrete was investigated. The objective of inserting rubber sheet into the middle layer was to act as a trapping layer to prevent bullets from ricocheting off the panel. Two test series were carried out: (1)investigation on energy absorption of each materials and (2)investigation on impact behavior of multilayer panel. The results from the 1st test series were used in the design of multilayer panels used in the 2nd series. The target impact energy of the bullet was 607 J. The multilayer panels were designed to have energy level ranging from 450 to 750 J. The panels were subjected impact by 9 mm caliber bullet with velocity of about 398 m/s. Results showed that the panels with impact energy absorption (IEA)level lower than the kinetic energy of the bullet (607 J.)failed by perforation. The panels with IEA level equal to or higher than 607 J. exhibited penetration failure mode with circular spalling at the back surface. There was no bullet ricocheting that occurred beyond this IEA level. At the level of IEA higher than 672 J, the failure mode shifted to penetration without visible damage at the back surface.

    DOI Scopus

  • Thermally induced dynamics of deployable solar panels of nanosatellite

    Ibrahim S., Yamaguchi E.

    Aircraft Engineering and Aerospace Technology    91 ( 7 ) 1039 - 1050   2019年07月  [査読有り]

     概要を見る

    © 2019, Emerald Publishing Limited. Purpose: This study aims to predict the types of thermally induced dynamics (TID) that can occur on deployable solar panels of a small form factor satellite, CubeSat which flies in low Earth orbit (LEO). The TID effect on the CubeSat body is examined. Design/methodology/approach: A 3U CubeSat with four short-edge deployable solar panels is considered. Time historic temperature of the solar panels throughout the orbit is obtained using a thermal analysis software. The results are used in numerical simulation to find the structural response of the solar panel. Subsequently, the effect of solar panel motion on pointing the direction of the satellite is examined using inertia relief method. Findings: The thermal snap motion could occur during eclipse transitions due to rapid temperature changes in solar panels’ cross-sections. In the case of asymmetric solar panel configuration, noticeable displacement in the pointing direction can be observed during the eclipse transitions. Research limitations/implications: This work only examines an LEO mission where the solar cells of the solar panels point to the Sun throughout the daylight period and point to the Earth while in shadow. Simplification is made to the CubeSat structure and some parameters in the space environment. Practical implications: The results from this work reveal several practical applications worthy of simplifying the study of TID on satellite appendages. Originality/value: This work presents a computational method that fully uses finite element software to analyze TID phenomenon that can occur in LEO on a CubeSat which has commonly used deployable solar panels structure.

    DOI Scopus

  • Seismic retrofit of steel truss bridge using buckling restrained damper

    Sosorburam P., Yamaguchi E.

    Applied Sciences (Switzerland)    9 ( 14 )   2019年07月  [査読有り]

     概要を見る

    © 2019 by the authors. Buckling Restrained Bracings (BRBs) are widely used to improve the seismic behavior of buildings. They are employed for bridges as well, but their application in this respect is limited. BRBs can also be used as a function of the individual damper rather than the structural component or the bracing, in which case the device may be called a Buckling Restrained Damper (BRD). Yet, such application has not been explored much. There are quite a few bridges designed according to the old design codes in Japan. Their seismic resistance may not be satisfactory for the current seismic design codes. Against this background, the behavior of a steel truss bridge under a large seismic load was investigated by nonlinear dynamic finite element analysis. Some members were indeed found to be damaged in the earthquake. Retrofitting is needed. To this end, the application of BRD was tried in the present study: a parametric study on the seismic behavior of the truss bridge with BRD was conducted by changing the length, the cross-sectional area, the location and the inclination of BRD. The effectiveness of BRD was then discussed based on the numerical results thus obtained. In all the analyses, ABAQUS was used.

    DOI Scopus

  • Comparison of solar radiation torque and power generation of deployable solar panel configurations on nanosatellites

    Ibrahim S., Yamaguchi E.

    Aerospace    6 ( 5 )   2019年05月  [査読有り]

     概要を見る

    © 2019 by the authors. Nanosatellites, like CubeSat, have begun completing advanced missions that require high power that can be obtained using deployable solar panels. However, a larger solar array area facing the Sun increases the solar radiation torque on the satellite. In this study, we investigated solar radiation torque characteristics resulting from the increased area of solar panels on board the CubeSats. Three common deployable solar panel configurations that are commercially available were introduced and their reference missions were established for the purpose of comparison. The software algorithms used to simulate a variety of orbit scenarios are described in detail and some concerns are highlighted based on the results obtained. The solar power generation of the respective configurations is provided. The findings are useful for nanosatellite developers in predicting the characteristics of solar radiation torques and solar power generation that will be encountered when using various deployable solar panels, thus helping with the selection of a suitable configuration for their design.

    DOI Scopus

  • Thermal distortion on deployable solar panels of cubesat in low earth orbit

    Ibrahim S., Yamaguchi E.

    Advances in the Astronautical Sciences    165   2107 - 2117   2018年01月  [査読有り]

     概要を見る

    © 2018 KASHYAP. This study predicts thermal distortion that can occur on deployable solar panels of a CubeSat in low earth orbit during eclipse transition of night-day. A 3U CubeSat with four short edge deployable solar panels that point to the Sun is considered. There are three steps of modeling involved. Firstly, the time historic temperature of the solar panel is characterized. Secondly, the results obtained are used in general stress analysis using a finite element software to obtain deformation of the solar panel. Finally, the effect of solar panel motion on the attitude displacement of the satellite is examined using inertia relief method. Results show that quasi-static deformation appears due to the difference in crosssection temperature of the solar panel. Brief thermal snap disturbances are likely to take place during eclipse transitions as well. As a result, the pointing direction of the CubeSat could be disturbed in the case when the solar panels are in asymmetric configuration.

    Scopus

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科研費獲得実績 【 表示 / 非表示

  • 既設鋼桁橋の維持管理性向上手法の開発

    基盤研究(C)

    研究期間:  2011年04月  -  2014年03月

    研究課題番号:  23560570

  • 鋼桁橋・鋼製橋脚の実変形挙動に関する解析的・実験的研究

    基盤研究(B)

    研究期間:  2003年04月  -  2005年03月

    研究課題番号:  15360244

  • 台湾集集地震により被災した橋梁の損傷メカニズム推定のための詳細調査

    基盤研究(B)

    研究期間:  2002年04月  -  2004年03月

    研究課題番号:  14404001

  • 既設鋼道路橋の疲労抵抗度診断とレトロフィッティング技術の開発に関する研究

    基盤研究(A)

    研究期間:  2001年04月  -  2004年03月

    研究課題番号:  13355020

 

担当授業科目 【 表示 / 非表示

  • 2018年度  材料力学特論

  • 2018年度  構造力学Ⅱ

  • 2018年度  構造力学Ⅰ

  • 2018年度  構造解析学特論

  • 2017年度  材料力学特論

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