佐藤 太裕 (サトウ モトヒロ)

工学研究院 機械・宇宙航空工学部門 機械材料システム教授
Last Updated :2024/12/10

■研究者基本情報

学位

  • 博士(工学), 北海道大学

Researchmap個人ページ

研究キーワード

  • パイプインパイプ
  • カーボンナノチューブ
  • 海洋パイプライン
  • 座屈
  • 複合構造
  • 応力集中
  • 微生物
  • 自然エネルギー
  • 粒状体材料
  • 曲げ特性
  • 曲げ変形
  • 粒子法
  • 個別要素法
  • パイプインパイプシステム
  • 劣化
  • 再生骨材
  • パイプライン
  • 合成構造
  • 靭性能
  • フレキシブルパイプインパイプ
  • 防災
  • コスト縮減
  • 構造工学
  • 山岳トンネル
  • 凍土
  • 寒冷地工学
  • 活動層
  • 温度解析
  • 支保構造物
  • 温度依存性

研究分野

  • フロンティア(航空・船舶), 船舶海洋工学
  • 社会基盤(土木・建築・防災), 安全工学
  • 社会基盤(土木・建築・防災), 社会システム工学
  • 社会基盤(土木・建築・防災), 土木材料、施工、建設マネジメント
  • 社会基盤(土木・建築・防災), 構造工学、地震工学

■経歴

経歴

  • 2023年04月 - 現在
    北海道大学大学院工学研究院 副研究院長(研究担当)
  • 2019年04月 - 現在
    北海道大学大学院, 工学研究院 機械・宇宙航空工学部門, 教授
  • 2012年02月 - 2019年03月
    北海道大学大学院, 工学研究院 北方圏環境政策工学部門, 准教授
  • 2017年06月 - 2017年09月
    英国ケンブリッジ大学, Visiting Academic Fellow
  • 2016年06月 - 2016年09月
    韓国仁川大学校, Visiting Professor
  • 2007年04月 - 2012年01月
    北海道大学大学院工学研究科(研究院), Graduate School of Engineering, 助教
  • 2010年09月 - 2011年03月
    英国インペリアルカレッジロンドン, Visiting Lecturer
  • 2002年04月 - 2007年03月
    北海道大学大学院工学研究科, Graduate School of Engineering, 助手
  • 2005年09月 - 2006年08月
    英国クランフィールド大学, Visiting Researcher

学歴

  • 1999年04月 - 2002年03月, 北海道大学大学院, 工学研究科社会基盤工学専攻 博士後期課程
  • 1997年04月 - 1999年03月, 北海道大学大学院, 工学研究科社会基盤工学専攻 修士課程
  • 1995年10月 - 1997年03月, 北海道大学, 工学部, 土木工学科
  • 1993年04月 - 1995年09月, 北海道大学, 教養部理Ⅰ系
  • 1990年04月 - 1993年03月, 北海道札幌北高等学校

委員歴

  • 2022年04月 - 現在
    北海道企業局 総合評価検討会委員
  • 2019年10月 - 現在
    北海道財務局, 国有財産北海道地方審議会委員, 政府
  • 2018年04月 - 現在
    北海道小樽建設管理部, 総合評価検討会委員, 自治体
  • 2018年01月 - 現在
    東日本高速道路(株)北海道支社, 狩勝第二トンネル土石流対策検討会, その他
  • 2016年01月 - 現在
    北海道札幌建設管理部, 総合評価審査委員会委員, 自治体
  • 2015年11月 - 現在
    鉄道・運輸機構, 北海道新幹線冬季対策委員会委員・幹事, その他
  • 2013年04月 - 現在
    東日本高速道路(株)北海道支社, トンネル技術検討会委員, その他
  • 2012年06月 - 現在
    道路管理技術センター, 道路管理技術委員会委員, その他
  • 2011年07月 - 現在
    Editorial Board, "Coupled Systems Mechanics(CSM)", An International Journal of Interactions of Structures, Fluids, Soil, Wind, Foundation and Multiple Systems, 学協会
  • 2009年10月 - 現在
    土木学会応用力学委員会, 委員, 学協会
  • 2002年04月 - 現在
    北海道土木技術会, 鋼道路橋研究委員会委員, その他
  • 2002年04月 - 現在
    北海道土木技術会, トンネル研究委員会委員, その他
  • 2013年04月 - 2018年03月
    北海道大学大学院工学研究院, 広報・情報管理室員, その他
  • 2015年10月 - 2016年03月
    札幌市, 道路トンネル補修計画検討会議委員, 自治体
  • 2011年04月 - 2013年03月
    土木学会構造工学委員会, 構造工学論文集編集小委員会委員(構造力学・構造工学一般部門担当), 学協会
  • 2008年04月 - 2009年12月
    日本鉄鋼連盟, 鋼構造ネットワーク北海道地区代表幹事, その他
  • 2008年05月 - 2009年04月
    土木学会, 土木学会誌編集委員(特集担当), 学協会
  • 2005年05月 - 2009年04月
    土木学会, 北海道支部幹事, 学協会
  • 2004年11月 - 2005年10月
    平成15年(2003年)十勝沖地震検討会委員・幹事, その他

学内役職歴

  • 大学院工学研究院副研究院長, 2023年4月1日 - 2025年3月31日

■研究活動情報

受賞

  • 2019年12月, 文部科学省 科学技術・学術政策研究所, 科学技術への顕著な貢献2019(ナイスステップな研究者)               
    竹が「軽さ」と「丈夫さ」を併せもつ理由の構造・材料力学的解明
    佐藤太裕
  • 2018年06月, 土木学会, 土木学会論文賞               
    竹の節・組織構造が織り成す円筒体としての合理的な構造特性の理論的解明
    佐藤太裕
  • 2016年02月, Editors’ suggestion, Physical Review E               
    佐藤太裕
  • 2016年01月, IASTEM Excellent Paper Award               
    佐藤太裕
  • 2014年02月, 北海道科学技術奨励賞(北海道知事表彰)               
    構造力学的手法を用いた新しい次世代型構造システムの研究開発
    佐藤太裕
  • 2010年07月, Selected paper, International Conference on Modelling and Simulation 2010 in Prague               
    佐藤太裕
  • 2008年12月, (財)国際科学技術財団(Japan Prize), 研究助成               
    佐藤太裕
  • 2002年04月, 土木学会北海道支部奨励賞               
    佐藤太裕
  • 2000年12月, 土木学会年次学術講演会優秀講演者表彰               
    佐藤太裕

論文

  • 力学のレンズから見えた「草」と「木」の境目
    佐藤太裕
    科学, 94, 3, 270, 272, 2024年03月, [招待有り], [筆頭著者, 最終著者, 責任著者]
    日本語, 論文集(書籍)内論文, 11970368
  • Self-buckling with initial imperfections: Application to trees
    Tohya Kanahama, Motohiro Sato
    International Journal of Engineering Science, 194, 103972, 103972, Elsevier BV, 2024年01月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), 11970368
  • Mechanical Instability of Heavy Column with Rotational Spring
    Tohya Kanahama, Carol Lee Chalermsin, Motohiro Sato
    Journal of Mechanics, Oxford University Press (OUP), 2023年12月14日, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), Abstract

    In previous research on the mechanical instability of trees based on mechanical theory, wild tree has been modeled as a cantilever which was perfectly attached to the ground. However, experimental research has identified two failure modes, including root turnover and self-buckling of the trunk. This suggests that the imperfect fixation caused by root-soil interaction must be considered when discussing tree stability. The purpose of this study is to clarify the self-buckling characteristics of wild trees considering soil instability. To account for the resistance moment caused by the interaction between the root and soil, trees as cantilevers fixed to the ground by a rotational spring were modeled. In this model, the self-buckling problem was formulated considering the rotational rigidity of the spring, and the formula derived for the critical height and buckling mode. As a result, the formula for critical height considering rotational rigidity was obtained, and it was found that the buckling modes can be classified into the rigid-body mode and beam mode based on the rotational rigidity. By comparing this result with the statistical law based on the measurement of real trees reported in previous research, it was determined that real trees were designed based on beam mode. This suggests that the wild tree skillfully balances the moment of resistance caused by the interaction between the root and soil to prevent “uprooting,” which is extremely fatal for trees. Moreover, it was also found that the safety factor of trees for self-buckling is ensured enough to prevent the beam mode., 11970368
  • Plant strategies for greatest height: tapering or hollowing
    Tohya Kanahama, Motohiro Sato
    Scientific Reports, 13, 1, Springer Science and Business Media LLC, 2023年10月24日, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), Abstract

    The tapered form and hollow cross-section of the stem and trunk of wild plants are rational mechanical approaches because they facilitate the plant simultaneously growing taller for photosynthesis and supporting its own weight. The purpose of this study is to clarify the advantages and disadvantages of tapering and hollowing from the perspective of the greatest probable height before self-buckling. We modelled woody plants using tapering or hollow cantilevers, formulated the greatest height before self-buckling, and derived a theoretical formula for the greatest probable height considering tapering and hollowing. This formula theoretically explains why almost all plants exhibit a tapered form: it allows for a greater height at an earlier growth stage than a hollow cross-section., 11970368
  • Impact of Land-Use Differences on Block-Size Distribution in Tokyo
    Yuri Akiba, Siyu Wang, Motohiro Sato, Hiroyuki Shima
    Journal of the Physical Society of Japan, 92, 10, Physical Society of Japan, 2023年10月15日, [査読有り]
    英語, 研究論文(学術雑誌), 11970368
  • Mechanics-based classification rule for plants
    Tohya Kanahama, Motohiro Sato
    Proceedings of the National Academy of Sciences, 120, 41, Proceedings of the National Academy of Sciences, 2023年10月06日, [査読有り], [最終著者]
    英語, 研究論文(学術雑誌), The height of thick and solid plants, such as woody plants, is proportional to two-thirds of the power of their diameter at breast height. However, this rule cannot be applied to herbaceous plants that are thin and soft because the mechanisms supporting their bodies are fundamentally different. This study aims to clarify the rigidity control mechanism resulting from turgor pressure caused by internal water in herbaceous plants to formulate the corresponding scaling law. We modeled a herbaceous plant as a cantilever with the ground side as a fixed end, and the greatest height was formulated considering the axial tension force from the turgor pressure. The scaling law describing the relationship between the height and diameter in terms of the turgor pressure was theoretically derived. Moreover, we proposed a plant classification rule based on stress distribution., 11970368
  • Preparation of bamboo-derived structured cellulose and its evaluation as resin composite materials
    Hiroya Ishimaru, Misuzu Matsumoto, Takuya Yoshikawa, Motohiro Sato, Yuta Nakasaka, Takao Masuda
    Biomass and Bioenergy, 173, 106778, 106778, Elsevier BV, 2023年06月, [査読有り]
    英語, 研究論文(学術雑誌), 12050706
  • Bamboo: A Mechanically Optimum Design in Nature
    Hiroyuki Shima, Akio Inoue, Motohiro Sato
    Bamboo Science and Technology, 1, 29, Springer Nature Singapore, 2023年03月15日, [査読有り], [招待有り], [最終著者]
    英語, 論文集(書籍)内論文, 11970368
  • 竹取工学物語⑦ 科学技術に立脚した「現代・未来の竹取物語」
    佐藤太裕
    科学, 93, 3, 248, 253, 2023年03月, [招待有り], [筆頭著者, 責任著者]
    日本語, 論文集(書籍)内論文, 11970368
  • Rigidity control mechanism by turgor pressure in plants
    Tohya Kanahama, Satoru Tsugawa, Motohiro Sato
    Scientific Reports, 13, 1, Springer Science and Business Media LLC, 2023年02月04日, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), Abstract

    The bodies of herbaceous plants are slender, thin, and soft. These plants support their bodies through the action of turgor pressure associated with their internal water stores. The purpose of this study was to apply the principles of structural mechanics to clarify the underlying mechanism of rigidity control that is responsible for turgor pressure in plants and the reason behind the self-supporting ability of herbaceous plants. We modeled a plant a horizontally oriented thin-walled cylindrical cantilever with closed ends enclosing a cavity filled with water that is acted on by its own weight and by internal tension generated through turgor pressure. We derived an equation describing the plant’s consequent deflection, introducing a dimensionless parameter to express the decrease in deflection associated with the action of turgor pressure. We found that the mechanical and physical characteristics of herbaceous plants that would appear to be counter-productive from a superficial perspective increase the deflection decreasing effect of turgor pressure., 11970368
  • 竹取工学物語⑥ 竹の「しなり」と「形」を利用した先人たちの智恵と技術
    佐藤太裕
    科学, 93, 2, 167, 172, 2023年02月, [招待有り], [筆頭著者, 責任著者]
    日本語, 論文集(書籍)内論文, 11970368
  • 竹取工学物語⑤ 植物が「⾼さ」を稼ぐための⼯夫
    佐藤太裕
    科学, 93, 1, 70, 75, 2023年01月, [招待有り], [筆頭著者, 責任著者]
    日本語, 論文集(書籍)内論文, 11970368
  • 竹取工学物語④ 植物の茎や枝の断面が「丸」であるのは当たり前?
    佐藤太裕
    科学, 92, 12, 1103, 1108, 2022年12月, [招待有り], [筆頭著者, 責任著者]
    論文集(書籍)内論文, 11970368
  • 竹取工学物語③ ⽵の「維管束」がもつ⼒学的役割               
    佐藤太裕
    科学, 92, 11, 956, 961, 2022年11月, [招待有り], [筆頭著者, 責任著者]
    日本語, 論文集(書籍)内論文
  • Empirical Rule of Fruit Rind Fragmentation in Muskmelon Netting
    Yuri Akiba, Akari Ishibashi, Motohiro Sato, Hiroyuki Shima
    Journal of the Physical Society of Japan, 91, 10, Physical Society of Japan, 2022年10月15日, [査読有り]
    英語, 研究論文(学術雑誌), 11970368
  • 竹取工学物語② ⽵の「節」がもつ⼒学的役割               
    佐藤太裕
    科学, 92, 10, 872, 877, 2022年10月, [招待有り], [筆頭著者, 責任著者]
    日本語, 論文集(書籍)内論文
  • 竹取工学物語① 竹取の翁は優れたエンジニアだった?               
    佐藤太裕
    科学, 92, 9, 811, 815, 2022年09月, [招待有り], [筆頭著者, 責任著者]
    日本語, 論文集(書籍)内論文
  • Summation rules in critical self-buckling states of cylinders
    Tohya Kanahama, Motohiro Sato
    Mechanics Research Communications, 123, 103905, 103905, Elsevier BV, 2022年07月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), 11970368
  • Effective length of bamboo-like stiffened hollow cylindrical structures
    Ryo Nishiyama, Motohiro Sato
    Journal of Mechanics, 38, 250, 256, Oxford University Press (OUP), 2022年06月02日, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), ABSTRACT

    Hollow cylindrical structures are susceptible to local buckling because they flatten and significantly reduce their stiffness when they bend. Therefore, many previous studies aimed to improve the strength of pipelines and building structures were conducted. Our research group has focused on bamboo and has theoretically proven that stiffness anisotropy caused by bamboo's unique nodes and vascular bundles enhances the stiffness of cylindrical structures. In this study, to investigate this analytically, we carried out a finite-element analysis and succeeded in deriving a new dimensionless parameter that the stiffening effect of an anisotropic consideration. This result is applicable to a wide range of cylindrical structures, from thin-walled to thick-walled, and it is expected that bamboo-inspired bionic designs will be proposed in the future., 11970368
  • Structural rationalities of tapered hollow cylindrical beams and their use in Japanese traditional bamboo fishing rods
    Ryo Nishiyama, Motohiro Sato
    Scientific Reports, 12, 1, Springer Science and Business Media LLC, 2022年02月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), AbstractBamboo has historically been used in Japan as a structural material and for building tools such as fishing rods owing to its remarkable structural properties. In recent years, the materials used for manufacturing fishing rods have changed greatly owing to the development of composite materials; however, the basic slender tapered hollow cylindrical fishing rod design has remained unchanged throughout the long history of fishing. However, the mechanical rationale behind this structural design has not yet been sufficiently verified, and this study clarifies this. The analysis was performed by solving the nonlinear bending equation of a slender tapered cantilever beam with a concentrated load at the tip, which causes large deflection, using the Runge–Kutta method. The deflection curves and bending stresses were obtained, and the structural design to minimize the stresses was explored. Our results may prove useful for bamboo-inspired bionic design and bring to light our ancestors’ deep knowledge of natural materials and their advanced technological capabilities., 11970368
  • Mathematical modelling to determine the greatest height of trees
    Tohya Kanahama, Motohiro Sato
    Scientific Reports, 12, 1, Springer Science and Business Media LLC, 2022年02月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), AbstractThis study aimed to analyse the critical height of a column whose weight varies vertically in order to obtain a simple scaling law for a tree where the weight distribution considered. We modelled trees as cantilevers that were fixed to the ground and formulated a self-buckling problem for various weight distributions. A formula for calculating the critical height was derived in a simple form that did not include special functions. We obtained a theoretical clarification of the effect of the weight distribution of heavy columns on the buckling behaviour. A widely applicable scaling law for trees was obtained. We found that an actual tree manages to distribute the weight of its trunk and branches along its vertical extent in a manner that adequately secures its critical height. The method and findings of this study are applicable to a wide range of fields, such as the simplification of complicated buckling problems and the study of tree shape quantification., 11970368
  • A new taper index based on form-factor: application to three bamboo species (Phyllostachys spp.)
    Akio Inoue, Motohiro Sato, Hiroyuki Shima
    EUROPEAN JOURNAL OF FOREST RESEARCH, SPRINGER, 2021年09月, [査読有り]
    英語, 研究論文(学術雑誌), The form-factor for the stem surface area is directly proportional to the square root of the form-factor for the stem volume, i.e., the square root law of the form-factor. Although the square root law addresses the stems of coniferous trees, the nature of the proportional coefficient of the law has not been discussed. In this study, we demonstrated that the coefficient indicates the stem taper; therefore, it is named "Taper Index based on Form-Factor (TIFF)." We also examined the relationship between the form-factor for the culm surface area and the form-factor for the apparent culm volume of 570 culms across three bamboo species (Phyllostachys pubescens Mazel ex Houz., P. bambusoides Sieb. et Zucc., and P. nigra var. henonis). The square root law held true for all three bamboo species. The species-specific TIFF was determined to be 0.873 for P. pubescens, 0.897 for P. bambusoides, and 0.901 for P. nigra. This result implied that P. pubescens had a more tapering culm form compared to the other two species, while culm taper was similar between P. bambusoides and P. nigra. Our findings align with empirical observations of the culm taper of the bamboo species. Intra-species variation in TIFF was considerably small, allowing us to evaluate the species-specific culm taper from a small number of samples. Therefore, we conclude that TIFF provides a simple and useful method for quantifying species-specific culm or stem taper, and facilitates the estimation of merchantable or total volume.
  • テーパーを有する樹木の自重座屈に対する限界高さの導出
    金浜 瞳也, 藤村 高憲, 佐藤 太裕
    土木学会論文集A2(応用力学), 77, 1, 62, 71, 公益社団法人 土木学会, 2021年, [査読有り], [最終著者, 責任著者]
    日本語, 研究論文(学術雑誌),

    樹木はそれぞれの生存環境に対して的確に順応し,高く大きく成長する能力が求められる.そのため,樹木の形態は様々な力学的合理性を秘めており,その形態や成長則を構造力学的な視点から明らかにすることは,既成概念からは生み出すことのできない革新性と合理性を有する新たな製品や構造概念の創出を可能にすると考えられる.本研究は,テーパーを有する樹木の自重座屈に対する限界高さの理論解を導出し,樹木のテーパー形状が限界高さに与える影響を明らかにすることを目的とする.本研究により,テーパーを有する樹木の限界高さ方程式が得られ,それを解いて得られる理論解から簡便に利用可能な限界高さ算定式を導くとともに,導出した理論解と有限要素解の比較検証を行った.

  • Scaling law for the onset of the surface wrinkling of multilayer tubes
    Motohiro Sato, Kazusa Ishigami, Hiroyuki Kato, Yoshitaka Umeno, Hiroyuki Shima
    Extreme Mechanics Letters, 40, 100970, 100970, Elsevier BV, 2020年10月, [査読有り], [筆頭著者]
    英語, 研究論文(学術雑誌)
  • Corrugation of an unpaved road surface under vehicle weight
    C. Matsuyama, Y. Tanaka, M. Sato, H. Shima
    Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 476, 2241, 20200323, 20200323, The Royal Society, 2020年09月, [査読有り]
    英語, 研究論文(学術雑誌), Road corrugation refers to the formation of periodic, transverse ripples on unpaved road surfaces. It forms spontaneously on an initially flat surface under heavy traffic and can be considered to be a type of unstable growth phenomenon, possibly caused by the local volume contraction of the underlying soil due to a moving vehicle’s weight. In the present work, we demonstrate a possible mechanism for road corrugation using experimental data of soil consolidation and numerical simulations. The results indicate that the vertical oscillation of moving vehicles, which is excited by the initial irregularities of the surface, plays a key role in the development of corrugation.
  • Cross-Sectional Performance of Hollow Square Prisms with Rounded Edges
    Hiroyuki Shima, Nao Furukawa, Yuhei Kameyama, Akio Inoue, Motohiro Sato
    SYMMETRY-BASEL, 12, 6, MDPI, 2020年06月, [査読有り], [最終著者, 責任著者]
    英語, 研究論文(学術雑誌), Hollow-section columns are one of the mechanically superior structures with high buckling resistance and high bending stiffness. The mechanical properties of the column are strongly influenced by the cross-sectional shape. Therefore, when evaluating the stability of a column against external forces, it is necessary to reproduce the cross-sectional shape accurately. In this study, we propose a mathematical method to describe a polygonal section with rounded edges and vertices. This mathematical model would be quite useful for analyzing the mechanical properties of plants and designing plant-mimicking functional structures, since the cross-sections of the actual plant culms and stems often show rounded polygons.
  • Estimation of culm volume reduction factors in five bamboo species (Phyllostachys spp.)
    Inoue, A, Shimada, M, Sato, M, Shima, H
    Journal of Forestry Research, 30, 6, 2069, 2078, 2019年12月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Allometric equations for predicting the aboveground biomass of square bamboo, Chimonobambusa quadrangularis
    Inoue Akio, Koshikawa Kazuki, Sato Motohiro, Shima Hiroyuki
    JOURNAL OF FOREST RESEARCH, 2019年11月18日, [査読有り]
    英語, 研究論文(学術雑誌)
  • Buckling-induced band-gap modulation in zigzag carbon nanotubes
    Umeno Yoshitaka, Sato Masanobu, Sato Motohiro, Shima Hiroyuki
    PHYSICAL REVIEW B, 100, 15, 2019年10月08日, [査読有り]
    英語, 研究論文(学術雑誌)
  • On the atomistic energetics of carbon nanotube collapse from AIREBO potential
    Umeno Yoshitaka, Yachi Yu, Sato Motohiro, Shima Hiroyuki
    PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 106, 319, 325, Elsevier BV, 2019年02月, [査読有り]
    英語, 研究論文(学術雑誌)
  • Maximum size-density relationship in bamboo forests: Case study of Phyllostachys pubescens forests in Japan
    Akio Inoue, Motohiro Sato, Hiroyuki Shima
    Forest Ecology and Management, 425, 138, 144, Elsevier B.V., 2018年10月01日, [査読有り]
    英語, 研究論文(学術雑誌), Bamboo forests are likely to be subjected to self-thinning due to their rapid growth rate. In fully stocked bamboo forests, the stand density (ρ) was suggested to be inversely proportional to the square of mean diameter at breast height (D) (ρ ∝ D−2), differing from the conventional power-law for trees, i.e., Reineke equation (ρ ∝ D−1.6). Nevertheless, the validity and mechanism of the inverse-square law remained unclear, despite its significance for managing bamboo forests. In this study, we derived an allometric model that predicts the slope of the maximum size-density relationship (MSDR) between D and ρ on double logarithmic coordinates based on well-known ecological laws. The model indicates that the slope of −2 for bamboo is theoretically valid, with the difference in the slope between bamboo and trees being caused by their differences in inner-culm (or inner-stem) structure. We also determined the MSDR empirically by compiling data of 415 Phyllostachys pubescens Mazel ex Houz. pure stands across Japan. The obtained MSDR describes the upper boundary of the D-ρ relationship well, with a slope of −1.996 that is very close to − 2. We further established a stand density management diagram of P. pubescens stands based on the MSDR. This diagram allows forest managers to regulate ρ depending on D as well as management purposes (production of bamboo shoot, bamboo charcoal and culm wood).
  • Axial buckling behavior of single-walled carbon nanotubes: Atomistic structural instability analysis
    Masanobu Sato, Hiroyuki Shima, Motohiro Sato, Yoshitaka Umeno
    Physica E: Low-Dimensional Systems and Nanostructures, 103, 130, 142, Elsevier B.V., 2018年09月01日, [査読有り]
    英語, 研究論文(学術雑誌), To reveal the atomistic scale mechanism of buckling of single-walled carbon nanotubes (SWCNTs) under axial compression, we carried out molecular dynamics (MD) simulation and atomistic structural instability (ASI) analysis. The ASI analysis enables us to reveal the development of ‘latent’ instability modes until buckling of structure, which cannot be clarified with MD alone. Euler-type buckling was found in relatively thin and long nanotube models, while buckling triggered by change of cross-sectional shape (i.e., radial buckling) was found in thick and short models. With growing radius, a crossover between the Euler-type and radial buckling modes was clearly found in the ASI analysis. Even when the deformation behavior was apparently the same, the buckling can be triggered by different instability modes. We also analyzed the structural instability using the Flügge theory based on linear continuum mechanics (LCM) to compare the results with the ASI analysis. Initial eigenvalues and development of instability modes were different between the ASI and LCM results, leading to a significant deviation of buckling strain and instability crossover points. We investigated the effect of chirality of CNT which is difficult to explain by LCM.
  • Allometric equations for predicting culm surface area of three bamboo species (Phyllostachys spp.)
    Akio Inoue, Yoshiyuki Miyazawa, Motohiro Sato, Hiroyuki Shima
    Forests, 9, 6, MDPI AG, 2018年05月25日, [査読有り]
    英語, 研究論文(学術雑誌), It is strongly debated whether bamboo forest ecosystems are a carbon sink or a carbon source because of insufficient knowledge regarding carbon loss via CO2 emissions from these forests. The surface area (S) of bamboo culms (stems) is important for estimating culm respiration, a major component of carbon cycling in bamboo forests. However, few studies have attempted to formulate predictive equations for S. In this study, we developed allometric equations for predicting S in three bamboo species grown in Kyushu Island, western Japan: Phyllostachys pubescens Mazel ex Houz., P. bambusoides Sieb. et Zucc. and P. nigra var. henonis. We used a power equation between S and diameter at breast height (D) and a linear equation between S and D × total culm length (H). The results indicated that P. bambusoides and P. nigra shared common site-independent equations. In contrast, P. pubescens required species-specific equations due to interspecific variation in culm slenderness and tapering. We also found that D was a better predictive variable than DH when quantifying S because of its satisfactory predictive performance and simplicity. These findings will be beneficial for evaluating the contribution of bamboo forest ecosystems to carbon cycling.
  • 多層カーボンナノチューブに生じる特異な断面座屈挙動の分子動力学解析
    谷内 湧, 梅野 宜崇, 島 弘幸, 佐藤 太裕
    土木学会論文集A2(応用力学), 74, 1, 51, 62, 公益社団法人 土木学会, 2018年, [査読有り], [最終著者, 責任著者]
    日本語, 研究論文(学術雑誌), 本研究は,一定圧力を作用させたカーボンナノチューブの断面座屈挙動を,分子動力学法によって精査することを目的とした.また,分子動力学法と薄肉円筒シェル理論の各々によって得られた結果を比較し,それらの適用限界を検証したうえで,カーボンナノチューブの直径や層数がその座屈特性に与える影響を調べた.更に,後座屈領域の時間発展追跡計算が可能という分子動力学法の利点を生かして,シェル理論では解析が困難な大変形過程の定量的検証と載荷-除荷曲線の導出を行った.
  • Dynamics of washboard road formation driven by a harmonic oscillator
    Teeranai Srimahachota, Hao Zheng, Motohiro Sato, Shunji Kanie, Hiroyuki Shima
    PHYSICAL REVIEW E, 96, 6, AMER PHYSICAL SOC, 2017年12月, [査読有り]
    英語, 研究論文(学術雑誌), Granular surfaces subjected to repeated passage often spontaneously develop a corrugated pattern. In this study, we scrutinized the growth dynamics of surface corrugation in a self-rotating sand bed that is traced by the edge of a vertically oscillating arm. We found that both the rotation velocity and the frequency of the oscillator strongly affect the occurrence rate of corrugation as well as the time evolution in the corrugation pattern, due to the intermittent collision between the oscillator and sand bed. We also discovered that the growth dynamics involves two distinct collective modes that describe the translational motion of the corrugation pattern on the sand bed.
  • Universal node distribution in three bamboo species (Phyllostachys spp.)
    Akio Inoue, Shiori Tochihara, Motohiro Sato, Hiroyuki Shima
    TREES-STRUCTURE AND FUNCTION, 31, 4, 1271, 1278, SPRINGER HEIDELBERG, 2017年08月, [査読有り]
    英語, 研究論文(学術雑誌), Bamboo exhibits unique structural properties that distinguish it from most other woody plants. One of the most remarkable properties is that the long hollow culm is separated into many small chambers by a sequence of nodes. The node distribution along the culm is, in general, sparse at the mid-culm and dense near the ends of the culm. In this study, we examined the intraspecific and interspecific variation in the node distribution of three species of the genus Phyllostachys (Phyllostachys pubescens Mazel ex Houz., Phyllostachys nigra var. henonis and Phyllostachys nigra Munro) with different culm sizes. The node distribution followed a single fitting curve via the normalization procedure, indicating the existence of a hidden universal law that governs the node distribution of the three species, despite their different appearances. Our findings also suggest that the node distribution along the mature culm could be determined at the stage of bamboo shoot by its base diameter.
  • POWER LAW OF CRITICAL BUCKLING IN STRUCTURAL MEMBERS SUPPORTED BY A WINKLER FOUNDATION
    M. Sato, S. Harasawa, Y. Konishi, T. Maruyama, S. J. Park
    JOURNAL OF MECHANICS, 33, 3, 369, 374, CAMBRIDGE UNIV PRESS, 2017年06月, [査読有り]
    英語, 研究論文(学術雑誌), In the fields of engineering, nanoscience, and biomechanics, thin structural members, such as beams, plates, and shells, that are supported by an elastic medium are used in several applications. There is a possibility that these thin structures might buckle under severe loading conditions; higher-order, complicated elastic buckling modes can be found owing to the balance of rigidities between the thin members and elastic supports. In this study, we have shown a new and simple 'power law' relation between the critical buckling strain (or loads) and rigidity parameters in structural members supported by an elastic medium, which can be modelled as a Winkler foundation. The following structural members have been considered in this paper: i) a slender beam held by an outer elastic support under axial loading, ii) cylindrical shells supported by an inner elastic core under hydrostatic pressure (plane strain condition), and iii) complete spherical shells that are filled with an inner elastic medium.
  • Bamboo-inspired optimal design for functionally graded hollow cylinders
    Motohiro Sato, Akio Inoue, Hiroyuki Shima
    PLOS ONE, 12, 5, PUBLIC LIBRARY SCIENCE, 2017年05月, [査読有り]
    英語, 研究論文(学術雑誌), The optimal distribution of the reinforcing fibers for stiffening hollow cylindrical composites is explored using the linear elasticity theory. The spatial distribution of the vascular bundles in wild bamboo, a nature-designed functionally graded material, is the basis for the design. Our results suggest that wild bamboos maximize their flexural rigidity by optimally regulating the radial gradation of their vascular bundle distribution. This fact provides us with a plantmimetic design principle that enables the realization of high-stiffness and lightweight cylindrical composites.
  • Atomistic model analysis of buckling behavior of compressed carbon nanotubes
    Yoshitaka Umeno, Masanobu Sato, Hiroyuki Shima, Motohiro Sato
    Solid State Phenomena, 258, 61, 64, Trans Tech Publications Ltd, 2017年, [査読有り]
    英語, 研究論文(国際会議プロシーディングス), We carried out the atomistic structural instability (ASI) analysis with an empirical interatomic potential for carbon nanotubes (CNTs) under axial compression with the aim to reveal the mechanism of buckling. We investigated how ‘latent’ instability modes develop until one of them is activated at the structural instability. For pristine single-walled carbon nanotubes (SWCNTs), Euler-type buckling was found in relatively thin nanotubes, while buckling modes corresponding to change in the cross-sectional shape (radial buckling) were found in thick nanotubes. The crossover between the Euler-type buckling and radial buckling modes was clearly seen in the ASI analysis. While the reduction of Hessian eigenvalues in the pristine nanotubes and nanotubes with a vacancy is nearly linear until instability, rapid decrease of eigenvalues just before instability was found in models with Stone-Wales defects. This is due to localization of instability mode vectors around the defects that tends to arise before structural instability.
  • Cross-sectional deformation in multi-walled carbon nanotubes under hydrostatic pressure
    Motohiro Sato, Yu Yachi, Ikuyo Koike, Hiroyuki Shima, Yoshitaka Umeno
    Solid State Phenomena, 258, 65, 68, Trans Tech Publications Ltd, 2017年, [査読有り]
    英語, 研究論文(国際会議プロシーディングス), This contribution provides simulated results of cross-sectional deformations observed in carbon nanotubes under high pressure. Molecular dynamics (MD) simulations were performed to explore radial buckling characteristics of multi-walled carbon nanotubes, and confirmed a variety of large-amplitude deformation modes. The energetically stable deformation mode turned out to be strongly dependent on the diameter of the innermost tube and the number of concentric walls. Critical buckling pressure obtained by MD simulations was compared with that estimated from a continuum elastic approximation, by which the validity of the continuum approximation was assessed.
  • Self-adaptive formation of uneven node spacings in wild bamboo
    Hiroyuki Shima, Motohiro Sato, Akio Inoue
    PHYSICAL REVIEW E, 93, 2, AMER PHYSICAL SOC, 2016年02月, [査読有り]
    英語, 研究論文(学術雑誌), Bamboo has a distinctive structure wherein a long cavity inside a cylindrical woody section is divided into many chambers by stiff diaphragms. The diaphragms are inserted at nodes and thought to serve as ring stiffeners for bamboo culms against the external load; if this is the case, the separation between adjacent nodes should be configured optimally in order to enhance the mechanical stability of the culms. Here, we reveal the hitherto unknown blueprint of the optimal node spacings used in the growth of wild bamboo. Measurement data analysis together with theoretical formulations suggest that wild bamboos effectively control their node spacings as well as other geometric parameters in accord with the lightweight and high-strength design concept.
  • Self-adaptive formation of uneven node spacings in wild bamboo
    Hiroyuki Shima, Motohiro Sato, Akio Inoue
    Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 93, 2016年02月, [査読有り]
    © 2016 American Physical Society.Bamboo has a distinctive structure wherein a long cavity inside a cylindrical woody section is divided into many chambers by stiff diaphragms. The diaphragms are inserted at nodes and thought to serve as ring stiffeners for bamboo culms against the external load; if this is the case, the separation between adjacent nodes should be configured optimally in order to enhance the mechanical stability of the culms. Here, we reveal the hitherto unknown blueprint of the optimal node spacings used in the growth of wild bamboo. Measurement data analysis together with theoretical formulations suggest that wild bamboos effectively control their node spacings as well as other geometric parameters in accord with the lightweight and high-strength design concept.
  • Atomistic model analysis of deformation of carbon nanotubes under axial compression               
    M. Sato, Y. Umeno
    Key Engineering Materials, 725, 451, 455, 2016年, [査読有り]
    英語, 研究論文(国際会議プロシーディングス)
  • 竹の節・組織構造が織り成す円筒体としての合理的な構造特性の理論的解明
    佐藤 太裕, 谷垣 俊行, 佐藤 諭佳, 島 弘幸, 井上 昭夫
    土木学会論文集A2(応用力学), 72, 2, I_25, I_34, 公益社団法人 土木学会, 2016年, [査読有り]
    日本語, 自然界に生息するタケは中空円筒であり,かつ節と組織構造を有する植物である.これは適者生存の厳しい環境下でできるだけ強く,高く生育するためにタケ自身が進化の過程で獲得してきた形態であり,力学的に極めて高い合理性を有すると考えられる.本研究は,タケの生態を構造力学的に紐解き,節配置の高さ方向分布と維管束の横断面内分布の不均一性が織り成す力学的優位性を実証するものである.この研究により,曲げを受けるタケの節配置による断面偏平抑制効果を剛性に関する異方性を考慮した無次元パラメータにより記述し,タケが外力により生じる曲げモーメント分布に合わせて断面偏平を効率的に抑制していること,また横断面内維管束分布は曲げ剛性を高めるように効果的に配置されていることが初めて理論的に示された.
  • HELICAL BUCKLING OF SLENDER BEAM STRUCTURES SURROUNDED BY AN ELASTIC MEDIUM
    S. Harasawa, M. Sato
    JOURNAL OF MECHANICS, 31, 3, 241, 247, CAMBRIDGE UNIV PRESS, 2015年06月, [査読有り]
    英語, 研究論文(学術雑誌), The goal of this study was to investigate analytically the buckling phenomena of slender beam structures embedded in an elastic medium. In such cases, there is a possibility that spiral-shaped buckling modes can occur due to the restraining effect of the surrounding medium. As a result of analytical investigations, helical buckling occurs radically. Furthermore the pitch of the helix does not fluctuate as the radius of the helix increases. The interesting mechanical implications of the embedding effect are demonstrated by the theoretical approach established in this study.
  • INTERLAYER COUPLING EFFECT ON BUCKLING MODES OF SPHERICAL BILAYERS
    M. Sato, Y. Konishi, S. -J. Park
    JOURNAL OF MECHANICS, 31, 1, 29, 36, CAMBRIDGE UNIV PRESS, 2015年02月, [査読有り]
    英語, 研究論文(学術雑誌), This study examined the critical buckling characteristics of hydrostatically pressurized double-walled complete spherical shells. An analytical model based on small deflection thin shell theory is presented; the equations are solved in conjunction with variational principles. Axisymmetric and inextensional assumptions are not initially used in the exact formulation. This approach therefore avoids any discussion about the validity of the solution and allows the model to be extended to cover more generic nonaxisymmetric cases with relative ease. The analytical results are presented using illustrative buckling modes. Based on the developed formulation, only axisymmetric eigenmodes were found to occur despite the inclusion of the effect of interactions between outer and inner shells. Critical modes that are symmetric or antisymmetric about the equator may be determined depending on the combination of the stiffness connecting the outer and inner shells and the radius-to-wall thickness ratios.
  • Molecular Dynamics Study of Radial Corrugation in Carbon Nanotubes
    Hiroyuki Shima, Yoshitaka Umeno, Motohiro Sato
    MECHANICS OF ADVANCED MATERIALS AND STRUCTURES, 22, 6, 423, 427, TAYLOR & FRANCIS INC, 2015年, [査読有り]
    英語, 研究論文(学術雑誌), Molecular dynamics simulations of multiwalled carbon nanotubes under hydrostatic pressure are performed to elucidate the novel class of radial buckling in the systems. It is revealed by all-atom simulations that the initial circular cross section transforms into a flower-like wavy configuration at critical pressure on the order of hundreds mega pascals or less. This kind of radial buckling, called radial corrugation, originates from the competition of the three relevant energies in the system: in-plane strain energy, van der Waals interaction energy between adjacent tubes, and out-of-plane bending energy. Their possible consequences for physical properties of carbon nanotubes are also discussed.
  • Brazier effect of single- and double-walled elastic tubes under pure bending
    Motohiro Sato, Yuta Ishiwata
    STRUCTURAL ENGINEERING AND MECHANICS, 53, 1, 17, 26, TECHNO-PRESS, 2015年01月, [査読有り]
    英語, 研究論文(学術雑誌), The cross sections of hollow cylindrical tubes ovalise under a pure bending condition, and this reduces their flexural stiffness as their curvatures increase. It is important to accurately evaluate this phenomenon, known as the, Brazier effect., to understand the bending behaviour of the systems considered. However, if the tubes are supported by an elastic medium or foundation, the ovalisation displacements of their cross sections may decrease. From this point of view, the purpose of this research is to analytically investigate the bending characteristics of single-and double-walled elastic tubes contacted by an elastic material by considering the Brazier effect. The Brazier moment, which is the maximum moment-carrying capacity of the ovalised cross section, can be calculated by introducing the strain energy per unit length of the tube in terms of the degree of ovalisation for the tube and the curvature. The total strain energy of the double-walled system is the sum of the strain energies of the outer and inner tubes and that of the compliant core. Results are comparatively presented to show the variation in the degree of ovalisation and the Brazier moment for single-and double-walled tubes.
  • Atomistic origin of radial corrugation in a few-walled carbon nanotubes: A molecular dynamics study
    Yoshitaka Umeno, Ikuyo Koike, Ayako Kusano, Hiroyuki Shima, Motohiro Sato
    PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, 65, 135, 140, ELSEVIER SCIENCE BV, 2015年01月, [査読有り]
    英語, 研究論文(学術雑誌), We perform molecular dynamics simulations of a few-walled (with 3-4 walls) carbon nanotubes using empirical interatomic potential. We demonstrate that the radial corrugation occurs in such thin nanotubes under hydrostatic pressure, which is apparently similar to the corrugation in thicker (e.g., several tens-walled) nanotubes that had been predicted using continuum mechanics approximation. The mechanism underlying the corrugation of a few-walled nanotubes, however, is found to be much distinct from thick nanotubes; i.e., the sp(3) bonds between adjacent concentric walls and registry of atom arrangement take important roles in the formation and stabilization of corrugation modes in a few-walled nanotubes. (C) 2014 Elsevier B.V. All rights reserved.
  • 竹はなぜ節をもつのか?~剛と柔が共存する竹形態の妙~
    古屋健, 岡本佳子, 佐藤諭佳, 佐藤太裕, 島弘幸
    形の科学会誌, 29, 2, 156, 157, 2014年11月
    日本語
  • Suppression of Brazier Effect in Multilayered Cylinders
    Hiroyuki Shima, Motohiro Sato, Sung-Jin Park
    ADVANCES IN CONDENSED MATTER PHYSICS, 2014, HINDAWI PUBLISHING CORPORATION, 2014年, [査読有り]
    英語, 研究論文(学術雑誌), When a straight hollow tube having circular cross-section is bent uniformly into an arc, the cross-section tends to ovalize or flatten due to the in-plane stresses induced by bending; this ovalization phenomenon is called the Brazier effect. The present paper is aimed at theoretical formulation of the Brazier effect observed in multilayered cylinders, in which a set of thin hollow cylinders are stacked concentrically about the common axis. The results indicate that mechanical couplings between stacked cylinders are found to yield pronounced suppression of the cross-sectional ovalization. Numerical computations have been performed to measure the degree of suppression in a quantitative manner and to explore how it is affected by the variations in the bending curvature, the number of stacked cylinders, and the interlayer coupling strength.
  • 分子動力学法を用いた多層カーボンナノチューブの波状変形挙動解析
    小池育代, 草野彩子, 佐藤太裕, 梅野宜崇, 島弘幸
    土木学会論文集 A2(応用力学)(Web), 70, 2, I.25-I.32 (J-STAGE), I_32, Japan Society of Civil Engineers, 2014年, [査読有り]
    日本語, 本研究では,円筒状のナノ炭素物質であるカーボンナノチューブについて,一定圧力作用時に発生が予想された特異な座屈変形モードを分子動力学法で再現することを目的とする.特に径が小さく原子数が少ない場合の解析を実施し,薄肉円筒シェル理論により得られた臨界座屈荷重との比較を行うことにより,円筒シェル理論の適用性についても言及する.さらに,一定圧力下での単層および多層カーボンナノチューブの座屈挙動を原子レベルで検証し,円筒シェル理論では解析できない座屈後の大変形挙動を追跡する.
  • STIFFENER INSERTION BASED VARIANCE IN RADIAL STIFFNESS OF MULTI-CONCENTRIC HOLLOW TUBES
    Motohiro Sato, Hiroyuki Shima, S-J Park
    JOURNAL OF MECHANICS, 29, 4, 583, 588, CAMBRIDGE UNIV PRESS, 2013年12月, [査読有り]
    英語, 研究論文(学術雑誌), ABSTRACT Shell theory solutions for radial buckling of multiply-concentric hollow cylinders are presented. Multi-cylindrical systems are those composed of two or more concentically mounted hollow tubes, wherein the annular space mediates inter-tube forces, attractive or repulsive depending on structural details of composites. Reflecting the multiple core-shell structures, the systems often exhibit peculiar radial buckling modes, which should be relevant to macro scale applications for deep water oil and gas transportation andmicroscale realization in lipid bilayer tubes. In this article, we focus on an illustrative example of such the multiply-tubular systems with nanometric dimension, the so-called multiwalled carbon nanotubes (MWNTs). Theoretical analysis based on a thin shell theory allows us to find anomalous radial buckling behaviors of MWNTs driven by hydrostatic pressure. The obtained buckling modes are characterized by petal-like wavy cross sections, which is what we call the radial corrugation of MWNTs. An important observation is the mechanical consequence of stiff core-tube insertion into the innermost hollow region of a given MWNT. The insertion results in a significant variance in the critical buckling pressure, above which the MWNT undergoes radial corrugation. The insertion-induced-variance in the critical pressure is due to the primary role of inter-tube interaction between adjacent constituent tubes, as explained within our theoretical model. Copyright © 2013 The Society of Theoretical and Applied Mechanics, R.O.C.
  • 投射体の最大到達距離に関する一考察
    平 久夫, 佐藤 太裕, 島 弘幸
    物理教育, 61, 4, 194, 197, 日本物理教育学会, 2013年12月, [査読有り]
    日本語
  • KALEIDOSCOPIC MODE CHANGE IN CROSS-SECTIONAL DEFORMATION OF REINFORCED CARBON NANOTUBES
    Sung-Jin Park, Hiroyuki Shima, Motohiro Sato
    INTERNATIONAL JOURNAL OF MODERN PHYSICS B, 27, 31, 1350179.1-1350179.9, WORLD SCIENTIFIC PUBL CO PTE LTD, 2013年12月, [査読有り]
    英語, 研究論文(学術雑誌), Cross-sectional deformation of multiwalled carbon nanotubes under isotropic radial pressure is investigated in a realm of continuum elastic approximation. The nanotube we assumed is subjected to the embedment into an elastic medium and stiffener insertion into the core cavity. Combination of the two reinforcement manipulations is found to cause kaleidoscopic mode changes in the radial corrugation, in which the cylindrical walls exhibit wavy patterns along the circumferential direction. Physical consequences of the diverse corrugation patters are also discussed.
  • Radial deformation and band-gap modulation of pressurized carbon nanotubes               
    H. Taira, H. Shima, Y. Umeno, M. Sato
    Coupled Systems Mechanics, 2, 2, 147, 157, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Effect of open-core screw dislocation on axial conductivity in semiconductor crystals               
    H. Taira, M. Sato
    Effect of open-core screw dislocation on axial conductivity in semiconductor crystals, 1, 3, 171, 182, 2013年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Embedding effect on the mechanical stability of pressurised carbon nanotubes
    Motohiro Sato, Hisao Taira, Tetsuro Ikeda, Hiroyuki Shima
    Journal of Nanomaterials, 2013, 3, ARTICLE ID 767249,1-9, 2013年, [査読有り]
    英語, 研究論文(学術雑誌), We elaborate on the cross-sectional deformation of carbon nanotubes embedded into a self-contracting host medium. The continuum elastic approach is used to formulate the mechanical energy of both the embedded nanotubes and the self-contracting outer medium with finite thickness. Our formula allows us to evaluate the critical radial pressure applied on the interface between the embedded nanotube and the outer contracting medium as well as the deformation mode that arises immediately above the critical pressure. An interesting mechanical implication of the embedding effect, that is, the power-law dependence of the critical pressure on the elastic modulus of the medium, is deduced by the theoretical approach established. © 2013 Motohiro Sato et al.
  • Buckling patterns of complete spherical shells filled with an elastic medium under external pressure
    M. Sato, M. A. Wadee, K. Iiboshi, T. Sekizawa, H. Shima
    INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 59, 1, 22, 30, PERGAMON-ELSEVIER SCIENCE LTD, 2012年06月, [査読有り]
    英語, 研究論文(学術雑誌), The critical buckling characteristics of hydrostatically pressurized complete spherical shells filled with an elastic medium are demonstrated. A model based on small deflection thin shell theory, the equations of which are solved in conjunction with variational principles, is presented. Axisymmetric and inextensional assumptions are not used initially in the exact formulation and the elastic medium is modelled as a Winkler foundation, i.e. using uncoupled radial springs with a constant foundation modulus that is independent of wave numbers of shell buckling modes. Simplified approximations based on a Rayleigh-Ritz approach are also introduced for the critical buckling pressure and the mode number with a considerable degree of accuracy. Characteristic modal shapes are demonstrated for a wide range of material and geometric parameters. A phase diagram is established to obtain the requisite thickness to radius, and stiffness ratios for a desired mode profile. The present exact formulation can be readily extended to apply to more general cases of non-axisymmetric buckling problems and the approximate method can be extended to the post-buckling range. (C) 2012 Elsevier Ltd. All rights reserved.
  • Thin-shell theory based analysis of radially pressurized multiwall carbon nanotubes
    Hiroyuki Shima, Susanta Ghosh, Marino Arroyo, Kohtaroh Iiboshi, Motohiro Sato
    COMPUTATIONAL MATERIALS SCIENCE, 52, 1, 90, 94, ELSEVIER SCIENCE BV, 2012年02月, [査読有り]
    英語, 研究論文(学術雑誌), The radial deformation of multiwall carbon nanotubes (MWNTs) under hydrostatic pressure is investigated within the continuum elastic approximation. A thin-shell theory, with accurate elastic constants and interwall couplings, allows us to estimate the critical pressure above which the original circular cross-section transforms into radially corrugated ones. The emphasis is placed on the rigorous formulation of the van der Waals interaction between adjacent walls, which we analyze using two different approaches. Possible consequences of the radial corrugation in the physical properties of pressurized MWNTs are also discussed. (C) 2011 Elsevier B.V. All rights reserved.
  • Hard-to-Soft Transition in Radial Buckling of Multi-Concentric Nanocylinders               
    S. -J. Park, M. Sato, T. Ikeda, H. Shima
    World Journal of Mechanics, 2, 1, 42, 50, 2012年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Approximate formulation for Bifurcation Buckling Loads of Axially Compressed Cylindrical Shells with an Elastic Core               
    M. Sato, K. Shimazaki
    Interactions and Multiscale Mechanics, 4, 4, 313, 320, 2011年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Elastic and Plastic Deformation of Carbon Nanotubes
    M. Sato
    PROCEEDINGS OF THE TWELFTH EAST ASIA-PACIFIC CONFERENCE ON STRUCTURAL ENGINEERING AND CONSTRUCTION (EASEC12), 14, 2366, 2372, ELSEVIER SCIENCE BV, 2011年, [査読有り]
    英語, 研究論文(国際会議プロシーディングス), Carbon nanotubes (CNTs) consist of a graphene sheet (two-dimensional hexagonal lattices of carbon atoms) rolled up into a cylinder. This nanoscale structure has generated enormous interest in the research field of science and engineering in the last decades because of its excellent mechanical properties. For example, Young's modulus of CNTs is estimated to be on the order of TPa (i.e., several times stiffer than steel) and the tensile strength is as high as tens of GPa. This means that CNTs are the stiffest and strongest materials on earth. On the other hand, CNTs are known to have its remarkable flexibility when subjected to external hydrostatic pressure and bending force. Owing to such mechanical properties, CNTs are regarded as an ideal material for superstrong nano-fiber and thus hold great promise for use as next-generation materials. It has also been broadly accepted that mechanical deformation of a carbon nanotube causes significant changes in its physical and chemical properties. Precise knowledge of its deformation mechanism and available geometry is, therefore, crucial for understanding the precise physics of CNT systems and in developing CNT-based applications. Here we introduce such remarkable elastic and plastic deformation properties of CNTs, as well as recent theoretical and experimental progresses in the field of many excellent CNT researches. (C) 2011 Published by Elsevier Ltd.
  • Hydrostatically pressurized buckling of complete spherical shells filled with an elastic medium
    SATO Motohiro, WADEE M. Ahmer, SEKIZAWA Takafumi, IIBOSHI Kohtaroh, SHIMA Hiroyuki
    土木学会論文集 A2(応用力学)(Web), 67, 2, I.15-I.22 (J-STAGE), 2011年, [査読有り]
    英語
  • Diverse corrugation pattern in radially shrinking carbon nanotubes
    Hiroyuki Shima, Motohiro Sato, Kohtaroh Iiboshi, Susanta Ghosh, Marino Arroyo
    Physical Review B - Condensed Matter and Materials Physics, 82, 8, 085401.1-085401.7, 2010年08月02日, [査読有り]
    英語, 研究論文(学術雑誌), Stable cross sections of multiwalled carbon nanotubes subjected to electron-beam irradiation are investigated in the realm of the continuum mechanics approximation. The self-healing nature of s p2 graphitic sheets implies that selective irradiation of the outermost walls causes their radial shrinkage with the remaining inner walls undamaged. The shrinking walls exert high pressure on the interior part of nanotubes, yielding a wide variety of radial-corrugation patterns (i.e., circumferentially wrinkling structures) in the cross section. All corrugation patterns can be classified into two deformation phases for which the corrugation amplitudes of the innermost wall differ significantly. © 2010 The American Physical Society.
  • Diverse corrugation pattern in radially shrinking carbon nanotubes
    Hiroyuki Shima, Motohiro Sato, Kohtaroh Iiboshi, Susanta Ghosh, Marino Arroyo
    PHYSICAL REVIEW B, 82, 8, AMER PHYSICAL SOC, 2010年08月, [査読有り]
    英語, 研究論文(学術雑誌), Stable cross sections of multiwalled carbon nanotubes subjected to electron-beam irradiation are investigated in the realm of the continuum mechanics approximation. The self-healing nature of sp(2) graphitic sheets implies that selective irradiation of the outermost walls causes their radial shrinkage with the remaining inner walls undamaged. The shrinking walls exert high pressure on the interior part of nanotubes, yielding a wide variety of radial-corrugation patterns (i.e., circumferentially wrinkling structures) in the cross section. All corrugation patterns can be classified into two deformation phases for which the corrugation amplitudes of the innermost wall differ significantly.
  • 完全没水係留浮体のスナップ荷重発生メカニズムに関する解析的検討
    佐藤太裕, 星崎心吾, 蟹江俊仁, 三上隆
    海洋開発論文集, 26, 801, 805, 2010年06月, [査読有り]
    日本語
  • パイプインパイプの軸圧縮座屈に対するコアの力学的役割
    佐藤太裕, 嶋崎賢太
    海洋開発論文集, 26, 531, 535, 2010年06月, [査読有り]
    日本語
  • STRUCTURAL MODELING OF CARBON NANOTUBES BASED ON CONTINUUM ELASTIC THEORY
    Motohiro Sato, Mohammad Rahimi, Marino Arroyo, Hiroyuki Shima
    PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON MODELLING AND SIMULATION 2010 IN PRAGUE (MS'10 PRAGUE), 387, 390, CZECH TECHNICAL UNIV PRAGUE, 2010年, [査読有り]
    英語, 研究論文(国際会議プロシーディングス), This study presents an applicability of a structural modeling of carbon nanotubes using continuum elastic thin cylindrical shell approximations. Molecular dynamics- or atomistic-based simulations are quite powerful and sophisticated analytical tools to accurately investigate the structural behaviors of carbon nanotubes under external loads. However, computational costs of such high performance numerical methods become expensive especially when we deals with large scale problems such as simulations of "multi"-walled carbon nanotubes (MWNTs). For this reason, continuum models can be frequently applied to analyze its structural and mechanical properties of carbon nanotubes as an alternative way, but the validity of using the continuum model is still under debate. In this study, we firstly formulate hydrostatically pressurized buckling behaviors of MWNTs based on the continuum elastic thin sell theory. Next, the analytical results, such as critical buckling pressures, obtained from shell theory based modeling are compared with the numerical results calculated from atomistic-based modeling.
  • 弾性体中多層カーボンナノチューブの半径方向圧力作用に対する特異な断面変形座屈モード発現の理論予測
    佐藤太裕, 島弘幸, 飯干晃太朗, 三上隆
    応用力学論文集(CD-ROM), 13, 19, 28, 2010年, [査読有り]
    日本語
  • CORE-TUBE MORPHOLOGY OF MULTIWALL CARBON NANOTUBES
    Motohiro Sato, Hiroyuki Shima, Kohtaroh Iiboshi
    INTERNATIONAL JOURNAL OF MODERN PHYSICS B, 24, 1-2, 288, 294, WORLD SCIENTIFIC PUBL CO PTE LTD, 2010年01月, [査読有り]
    英語, 研究論文(学術雑誌), The present paper investigates the cross-sectional morphology of Multiwalled Carbon Nanotubes (MWNTs) restrained radially and circumferentially by an infinite surrounding elastic medium, subjected to uniform external hydrostatic pressure. In this study, a two-dimensional plane strain model is developed, assuming no variation of load and deformation along the tube axis. We find some characteristic cross-sectional shapes from the elastic buckling analysis. The effect of the surrounded elastic medium on the cross-sectional shape which occurs due to pressure buckling is focused on by the comparison with the shape for no elastic medium case in our discussion. It is suggested that in no embedded elastic medium cases, the cross-sectional shapes of inner tubes maintain circle or oval; on the other hand, an embedded medium may cause inner tube corrugation modes especially when the number of shells for MWNTs is small.
  • Pressure-induced structural transitions in multi-walled carbon nanotubes
    Hiroyuki Shima, Motohiro Sato
    PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 206, 10, 2228, 2233, WILEY-V C H VERLAG GMBH, 2009年10月, [査読有り]
    英語, 研究論文(学術雑誌), We demonstrate a novel cross-sectional deformation, called the radial corrugation, of multi-walled carbon nanotubes (MWNTs) under hydrostatic pressure. Theoretical analyses based on the continuum elastic approximation have revealed that MWNTs consisting of more than ten concentric walls undergo elastic deformations at critical pressure p(c) similar or equal to 1 GPa, above which the circular shape of the cross-section becomes radially corrugated. Various corrugation modes have been observed by tuning the innermost tube diameter and the number of constituent walls, which is a direct consequence of the core-shell structure of MWNTs.
    [GRAPHICS]
    Cross-sectional views of MWNT under high hydrostatic pressure: elliptic deformation with the mode index n = 2 (left), and radial corrugations with n = 5 (center), and n = 6 (right). The index it indicates the circumferential wave number of the deformed cross-section. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
  • フレキシブルパイプインパイプの提案とその曲げ特性に関する基礎的検討
    佐藤太裕, 渡辺香奈, 白石圭祐, 蟹江俊仁, 赤川敏
    海洋開発論文集, 25, 737, 740, 2009年06月, [査読有り]
    日本語
  • Buckling Characteristics of Multiwalled Carbon Nanotubes under External Pressure               
    M. Sato, H. Shima
    Interactions and Multiscale Mechanics, 2, 2, 209, 222, 2009年, [査読有り]
    英語, 研究論文(学術雑誌)
  • Multiple radial corrugations in multiwalled carbon nanotubes under pressure
    Hiroyuki Shima, Motohiro Sato
    NANOTECHNOLOGY, 19, 49, 495705 (8 PP.), IOP PUBLISHING LTD, 2008年12月, [査読有り]
    英語, 研究論文(学術雑誌), Radial elastic corrugation of multiwalled carbon nanotubes under hydrostatic pressure is demonstrated by using the continuum elastic theory. Various corrugation patterns are observed under a pressure of several GPa, wherein the stable cross-sectional shape depends on the innermost tube diameter D and the total number N of concentric walls. A phase diagram is established to obtain the requisite values of D and N for a desired corrugation pattern among choices. In all corrugation patterns, the cylindrical symmetry of the innermost tube is maintained even under high external pressure.
  • Static displacement and elastic buckling characteristics of structural pipe-in-pipe cross-sections
    M. Sato, M. H. Patel, F. Trarieux
    STRUCTURAL ENGINEERING AND MECHANICS, 30, 3, 263, 278, TECHNO-PRESS, 2008年10月, [査読有り]
    英語, 研究論文(学術雑誌), Structural pipe-in-pipe cross-sections have significant potential for application in offshore oil and gas production systems because of their property that combines insulation performance with structural strength in an integrated way. Such cross-sections comprise inner and outer thin walled pipes with the annulus between them fully filled by a selectable thick filler material to impart an appropriate combinations of properties. Structural pipe-in-pine cross-sections can exhibit several different collapse mechanisms and the basis of the preferential occurrence of one over others is of interest. This paper presents an elastic analyses of a structural pipe-in-pine cross-section when subjected to external hydrostatic pressure. It formulates and solves the static and elastic buckling problem using the variational principle of minimum potential energy. The paper also investigates a simplified formulation of the problem where the outer pipe and its contact with the filler material is considered as a 'pipe on an elastic foundation'. Results are presented to show the variation of elastic buckling pressure with the relative elastic modulus of the filler and pipe materials, the filler thickness and the thicknesses of the inner and outer pipes. The range of applicability of the simplified 'pipe on an elastic foundation' analysis is also presented. A brief review of the types of materials that could be used as the filler is combined with the results of the analysis to draw conclusions about elastic buckling behaviour of structural pipe-in-pipe cross-section.
  • パイプインパイプ断面を有する海洋パイプラインの曲げ特性に対するコアの力学的役割について
    嶋崎 賢太, 佐藤 太裕, 蟹江 俊仁, 三上 隆
    海洋開発論文集, 24, 24, 1047, 1050, Japan Society of Civil Engineers, 2008年06月, [査読有り]
    日本語, Structural pipe-in-pipe cross-sections have significant potential for application in offshore oil and gas production systems because of their property that combines thermal insulation performance with structural strength and self weight in an integrated way. Such cross-sections comprise inner and outer thin walled pipes with the annulus between them fully filled by a selectable filler material to impart an appropriate combination of properties. For offshore pipelines, bending characteristics become one of the most important factors for the structural design of the pipelines. The purpose of this research is to investigate the bending characteristics of such pipe-in-pipe systems analytically by considering the Brazier effect. Results are presented to show the variation of the degree of ovalization and bending moment with the relative elastic modulus of the filler and pipe materials and the filler thickness.
  • 係留索配置形状が完全没水型係留浮体の三次元動揺特性に及ぼす影響
    佐藤 太裕, 星崎 心吾, 蟹江 俊仁, 三上 隆
    海洋開発論文集, 24, 24, 981, 985, Japan Society of Civil Engineers, 2008年06月, [査読有り]
    日本語, For a type of "perfectly underwater"structures moored by some tension legs, namely submerged floating structures, the dynamic behaviors of the floating body are expected to involve many severe design and computational problems. In addition, three dimensional motions with six degrees of freedom induced by some external forces like strong waves and earthquakes may be very complex and it is difficult to explain the mechanisms of the behavior accurately.<BR>This paper presents the three dimensional dynamic response characteristics of the submerged floating structures. Three dimensional restoring forces due to tension legs are introduced and dynamic properties such as natural period and fluctuating tension force are investigated here. Especially, we focus on the effect of tension leg arrangement on dynamic characteristics of submerged floating structure.
  • Mathematical analogy of a beam on elastic supports as a beam on elastic foundation
    Motohiro Sato, Shunji Kanie, Takashi Mikami
    APPLIED MATHEMATICAL MODELLING, 32, 5, 688, 699, ELSEVIER SCIENCE INC, 2008年05月, [査読有り]
    英語, 研究論文(学術雑誌), This paper presents the mathematical hypothesis that a beam on equidistant elastic supports (BOES) can be considered as a beam on an elastic foundation (BOEF) in static and free vibration problems. This modeling of BOES as BOEF is presumed to be applicable to a limited range of support stiffness, spacing and flexural rigidity of the beam. The authors investigate the applicability of the modeling of BOEF from the property of characteristic solutions obtained from governing equations of both BOES and BOEF. In this study, the formulation of BOES leads to governing difference equations, and the motions of BOEF are expressed by differential equations. This is because exact solutions must be employed in order to verify their analogy accurately. The characteristic solutions obtained from these two governing equations are compared to each other in order to investigate the relationship between them. (c) 2007 Elsevier Inc. All rights reserved.
  • Exact and simplified estimations for elastic buckling pressures of structural pipe-in-pipe cross sections under external hydrostatic pressure
    Motohiro Sato, Minoo H. Patel
    JOURNAL OF MARINE SCIENCE AND TECHNOLOGY, 12, 4, 251, 262, SPRINGER TOKYO, 2007年11月, [査読有り]
    英語, 研究論文(学術雑誌), Structural pipe-in-pipe cross sections have significant potential for application in offshore oil and gas production systems because they combine thermal insulation performance with structural strength and self weight in an integrated way. Such cross sections comprise inner and outer thin-walled pipes with the annulus between them fully filled by a selectable filler material to impart an appropriate combination of properties. Structural pipe-in-pipe cross sections can exhibit several different collapse mechanisms, and the basis of the preferential occurrence of one over the others is of interest. This article presents an exact analysis for predicting the elastic buckling behaviours of a structural pipe-in-pipe cross section when subjected to external hydrostatic pressure. Simplified approximations are also investigated for elastic buckling pressure and mode when the outer pipe and its contact with the filler material is considered as a pipe on an elastic foundation. Results are presented to show the variation of elastic buckling pressure with the relative elastic modulus of the filler and pipe materials, the filler thickness, and the thicknesses of the inner and outer pipes. Case studies based on realistic application scenarios are used to show that the simplified approximations are sufficiently accurate for practical structural design purposes.
  • Structural modeling of beams on elastic foundations with elasticity couplings
    Motohiro Sato, Shunji Kanie, Takashi Mikami
    MECHANICS RESEARCH COMMUNICATIONS, 34, 5-6, 451, 459, PERGAMON-ELSEVIER SCIENCE LTD, 2007年07月, [査読有り]
    英語, 研究論文(学術雑誌), A new simplified structural model and its governing equations for beams on elastic foundations with elastic coupling are proposed. This modeling system is simple but appropriate for the initial structural design of large-scale submerged floating-beam structures moored by tension legs spaced at uniform interval along the beam. The model is actually for beam on discrete elastic supports rather than on continuous elastic foundations. Therefore, the governing equations are based on finite difference calculus and solutions for beams on discrete elastic supports with elasticity coupling are also proposed. To clarify the applicability limit of the proposed model, the equivalence between a beam on discrete elastic supports and that on continuous elastic foundation is investigated by comparisons of characteristic solutions. (c) 2007 Elsevier Ltd. All rights reserved.
  • パイプインパイプ断面を有する海洋 パイプラインの静水圧作用時における簡易な座屈荷重評価式の検討
    佐藤 太裕, 嶋崎 賢太, 蟹江 俊仁, 三上 隆
    海洋開発論文集, 23, 23, 907, 911, Japan Society of Civil Engineers, 2007年06月, [査読有り]
    日本語, Structural pipe-in-pipe cross-sections have significant potential for application in offshore oil and gas production systems because of their property that combines thermal insulation performance with structural strength and self weight in an integrated way. Such cross-sections comprise inner and outer thin walled pipes with the annulus between them fully filled by a selectable filler material to impart an appropriate combination of properties. Structural pipe-in-pipe cross-sections can exhibit several different collapse mechanisms and the basis of the preferential occurrence of one over others is of interest. This paper presents a simplified evaluation method for predicting the elastic buckling behaviours of a structural pipe-in-pipe cross-section when subjected to external hydrostatic pressure. Results are presented to show the validity of the proposed simplified formulations for estimating the local and global buckling pressures.
  • 三次元流動解析に基づく底泥回収装置の検討
    蟹江 俊仁, 鈴木 雄太, 佐藤 太裕, 旭 幸司, 高橋 伸次郎, 井上 卓悦
    海洋開発論文集, 23, 23, 309, 314, Japan Society of Civil Engineers, 2007年06月, [査読有り]
    日本語, At the time being, deterioration in water quality of closed water body has become a serious issue for local fishery and accumulation of mud layer which covers lakebed has been thought as the cause of deterioration. Then, it can be said that maintenance and preservation of the water environment by retrieving those mud layer is one of the most important subjects to enhance and to promote regional economy in the vicinity with preserving precious marine resources.<BR>The authors have proposed a new retrieving method of lakebed mud on site. This method has been developed as an innovative way that requires neither additional chemicals for condensation of the mud nor a temporary yard for desiccation of the mud. After the first phase with indoor model experiment, it was confirmed that the method successfully retrieve the mud and an on-site experiment is now under planning. In this paper, the authors report a study result on the device, especially the shape of retrieving fan, with 3-D flow analysis. Through this study, important knowledge for designing the shape of fan was obtained in order to expect efficient retrieving. Though further experiment is necessary under various mud conditions to improve the efficiency, the method is getting close to a reality.
  • 極めて柔軟かつ厚いコアを有するパイプインパイプ断面の静水圧による局部座屈特性
    佐藤 太裕, PATEL Minoo H, TRARIEUX Florent
    応用力学論文集, 9, 25, 32, Japan Society of Civil Engineers, 2006年08月, [査読有り]
    日本語, This paper presents an analysis of local collapse mechanisms of a structural pipe-in-pipe cross-section with very soft and thick core when subjected to external hydrostatic pressure. It formulates and solves the elastic collapse problem using the variational principle of minimum potential energy. Effects of therelative stiffness between the outer/inner pipes and the core, and the core thickness on the critical external pressures and the collapse modes are investigated. The paper also proposes a simplified formulation of the localbuckling problem where the outer pipe and its contact with the filler material is considered as a 'ringon an elastic foundation'.
  • Free vibration characteristics of cylindrical shells partially buried in elastic foundations
    HG Tj, T Mikami, S Kanie, M Sato
    JOURNAL OF SOUND AND VIBRATION, 290, 3-5, 785, 793, ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD, 2006年03月, [査読有り]
    英語, 研究論文(学術雑誌), Free vibrations of cylindrical shells partially buried in elastic foundations based on the finite element method were examined. The shells are discretized into cylindrical finite elements and the distribution of the foundation in the circumferential direction is defined by the expansion of Fourier series. The present formulation can be simply applied to consider non-uniformities in the foundation both in the circumferential and longitudinal directions. Convergence issues with the present method are explained. Numerical results of the natural frequency and mode for various shell geometries and foundation parameters are given to provide a clearer picture of the shell characteristics in linear vibrations. The relative stiffness ratio of foundation and shell is discussed. The results of free vibration analysis for partially suspended shells on elastic foundations are also presented. (c) 2005 Elsevier Ltd. All rights reserved.
  • Response of Cylindrical Shells Partially Buried in Elastic Foundations to Impact Loads
    TJ Haryadi Gunawan, MIKAMI Takashi, KANIE Shunji, SATO Motohiro
    構造工学論文集 A, 52, 3, 1219, 1226, 2006年03月, [査読有り]
    英語
  • Free vibrations of fluid-filled cylindrical shells on elastic foundations
    HG Tj, T Mikami, S Kanie, M Sato
    THIN-WALLED STRUCTURES, 43, 11, 1746, 1762, ELSEVIER SCI LTD, 2005年11月, [査読有り]
    英語, 研究論文(学術雑誌), The free vibration characteristics of fluid-filled cylindrical shells on elastic foundations are presented by a semi-analytical finite element method. A shell is discretized into cylindrical finite elements where shell governing equations based shape functions in the longitudinal direction are used instead of the usual simple polynomials. Non-uniformities of the foundations in the circumferential and longitudinal directions are handled by the Fourier series and an element mesh Strategy, respectively. The fluid domain is described by the potential flow theory. The hydrodynamic pressure acting on shells is derived from the condition for dynamic coupling of the fluid-structure. The effect of fluid in a shell, shell geometries, and foundation parameters on the dynamic behavior of fluid-containing shells is investigated. Numerical results based on the present method converge more rapidly than those obtained by the simple polynomial formulation. The method is suitable for the problem considered due to its generality, simplicity, and potential for further development. (c) 2005 Elsevier Ltd. All rights reserved.
  • 凍土中に埋設された冷却ガスパイプラインの凍上変形とその簡易評価法
    蟹江 俊仁, 赤川 敏, 三上 隆, 佐藤 太裕, 金 高義
    土木学会論文集 = Proceedings of JSCE, 798, 157, 166, 土木学会, 2005年09月, [査読有り]
    日本語
  • Finite element analysis of cylindrical shells partially buried in elastic foundations
    H Gunawan, T Mikami, S Kanie, M Sato
    COMPUTERS & STRUCTURES, 83, 21-22, 1730, 1741, PERGAMON-ELSEVIER SCIENCE LTD, 2005年08月, [査読有り]
    英語, 研究論文(学術雑誌), A method for analyzing cylindrical shells partially buried in an elastic foundation based on the finite element method is presented by using the expansion of a Fourier series in the circumferential direction to define the distribution of the foundation. Numerical analysis of convergence of the results is presented for a gravity load. The effect of the foundation on the distribution of stress resultants was investigated. Numerical results are also given for the internal liquid pressure load. In addition, cylindrical shells partially suspended on elastic foundations are also analyzed. (c) 2005 Elsevier Ltd. All rights reserved.
  • Free Vibrations of Cylindrical Shells Partially Suspended on Elastic Foundations
    TJ Haryadi Gunawan, MIKAMI Takashi, KANIE Shunji, SATO Motohiro
    構造工学論文集 A, 51A, 1, 1, 10, 2005年03月20日
    英語
  • 底質改善工法開発のための底泥回収実験
    旭 幸司, 高橋 伸次郎, 井上 卓悦, 蟹江 俊仁, 佐藤 太裕, 鈴木 雄太
    海洋開発論文集, 21, 21, 879, 883, Japan Society of Civil Engineers, 2005年, [査読有り]
    日本語, At present, deterioration of water quality in closed water body has become a serious issue for the local fishery and an accumulated mud layer which covers lakebed has been thought as the cause of the deterioration. Then, it can be said that the maintenance and preservation of the water environment by retrieving the mud layer is one of the most important subjects to preserve and to promote the regional economy with maintaining precious marine resources.<BR>In this paper, the authors propose a new retrieving method of lakebed mud on site. This method has been developed as an innovative way that requires neither additional chemicals for condensation of the mud nor a temporary yard for desiccation of the mud. This research aims to obtain fundamental knowledge about the retrieving torque and its efficiency to establish this new method. The experimental result shows that the mud can be retrieved with the fan efficiently enough to adopt the method practically. However, further experiment is necessary under various mud conditions to improve the efficiency.
  • チルドガスパイプラインと凍土との相互作用評価について
    蟹江俊仁, 赤川敏, 佐藤太裕, 三上隆
    寒地技術論文・報告集, 20, 472, 478, 2004年10月
    日本語
  • 水中浮遊式トンネルの係数励振振動特性に関する基礎的検討
    佐藤 太裕, 蟹江 俊仁, 三上 隆
    応用力学論文集, 7, 1, 31, 38, 土木学会, 2004年08月, [査読有り]
    日本語
  • 海中固定構造物に作用する波力と断面形状の関係に関する一考察
    三倉寛明, 蟹江俊仁, 三上隆, 佐藤太裕
    海洋開発論文集, 20, 20, 85, 88, Japan Society of Civil Engineers, 2004年, [査読有り]
    日本語, Recently, completely submerged structure resting on piles is expected as a new alternative structure to bridge and/or immersed tunnel for relatively shallow-water crossing. In case of those structures, no change in buoyancy can be expected and only pile must resist against external wave force. As a result, the piles should have enough length to exert their friction strength against pulling out force due to wave. Since high safety factor for pulling out is required, reducing vertical force acting on piles becomes important for economical design. This study aims to evaluate the effect of sectional shape on the wave force and to introduce the relationship between sectional shape and vertical wave force acting on supporting structure.
  • 完全没水係留浮体の結合共振特性について
    佐藤太裕, 蟹江俊仁, 三上隆, 小室達明
    海洋開発論文集, 20, 20, 1277, 1282, Japan Society of Civil Engineers, 2004年, [査読有り]
    日本語, This paper deals with the characteristics of combination resonance for submerged floating structure. The combination resonance takes place in a vibratory system having multiple degrees-of-freedom and under parametric excitation. In this study, it is assumed that the floating structure is moored by some tension legs and located in the water between seabed and water surface. Due to such a structural form, there is much possibility that complicated dynamic phenomena like parametric excitation take place. The parametric excitation is caused by the time-varying tension force of tension legs. The time-varying tension force arises when some dynamic loads such as regular waves act on the floating body and the body moves in the water. In this paper, analytical studies are carried out to confirm the possibility of the occurrence of unstable motions by introducing Mathieu equations and effects of tension leg arrangements on the combination resonance characteristics are investigated in particular.
  • 係留索の周期的変動張力による水中係留浮体の動的不安定性
    佐藤太裕, 小室達明, 蟹江俊仁, 三上隆
    海洋開発論文集, 20, 20, 1283, 1286, Japan Society of Civil Engineers, 2004年, [査読有り]
    日本語, Submerged Floating Structure is a whole new type of strait crossing which is fixed in the water and supported by the balance between buoyancy and drag force of tension legs. This structure is expected to be widely applicable for railway, road, pedestrian walk and transportation system of material and fluid. In order to realize this construction technology, however, there are a lot of problems to be solved.<BR>One of the most important probrems is parametric excitation which is the response caused by time-varying tension force of legs. In this paper, the parametric excitation phenomena of Submerged Floating Structure are studied analytically and characteristics of the dynamic instability are investigated
  • 水中浮遊式トンネルの係数励振振動特性に関する基礎的検討
    佐藤 太裕, 蟹江 俊仁, 三上 隆, 小室 達明
    応用力学論文集, 7, 31, 38, Japan Society of Civil Engineers, 2004年, [査読有り]
    This paper deals with the characteristics of the parametric excitation, which is one of the dynamic instability phenomena, of Submerged Floating Tunnel. In this study, it is assumed that the structure is moored by some tension legs and located in the water between seabed and water surface. The parametric excitation is caused by the time tension force of tension legs. The time-varying tension force arises when some dynamic loads such as regular waves act on the floating body and the body moves in the water. The analytical studies are carried out to confirm the possibility of the occurrnce of unstable motions by introducing Mathieu-type equations in this study and effects of tension leg arrangements, viscous damping, quadratic damping and external forces on the parametric excitation characteristics are investigated in particular.
  • 係留索配置形状が水中係留浮体の動的特性に与える影響の評価
    佐藤太裕, 蟹江俊仁, 三上隆
    海洋開発論文集, 19, 19, 649, 652, Japan Society of Civil Engineers, 2003年, [査読有り]
    日本語, For a type of "perfectly underwater" structures moored by tension legs like Submerged Floating tunnel, dynamic behaviors of the floating body are expected to involve many severe design and computational problems. In addition, motions induced by some external forces like strong waves and earthquakes may be very complex and it is difficult to explain the mechanisms of the behavior accurately. Especially, dynamic characteristics in consideration of elasticity coupling caused by restoring force of tension leg arrangement have not been clear so far. When elasticity coupling can arise, restoring forces of tension legs associated with the rotation show some bad influences on the dynamic behaviors. From this point of view, we focus on the effect of tension leg arrangement on dynamic characteristics of submerged floating structure in this study.
  • 係留索の動的挙動を考慮した完全没水浮体の振動特性
    蟹江俊仁, 佐藤太裕, 三上隆
    海洋開発論文集, 19, 19, 653, 658, Japan Society of Civil Engineers, 2003年, [査読有り]
    日本語, In case of completely submerged floating structure, no change in buoyancy can beexpected with its dynamic motion and the restoring force fully depends on cables. Consequently, it is necessary to seize the relation between structural displacement and restoring force and to evaluate the effect ofnonlinear deformation of cables on the dynamic response. This study aims to evaluate the effect of deformation of mooring cable caused by self-weight, inertia and fluid force on the vibration of the structure. This paper introduces nonlinear equations of motion considering the dynamic behavior of the cables and investigates the effect of dynamic deformation of cables on whole behavior with numerical examples.
  • 弾性床上梁にモデル化した水中浮遊式トンネルの波浪応答特性
    佐藤太裕, 蟹江俊仁, 三上隆
    構造工学論文集 A, 48A, 1, 27, 34, 2002年03月, [査読有り]
    日本語
  • 動的問題における水中浮遊式トンネルと弾性床上梁の等価性に関する検討
    佐藤太裕, 蟹江俊仁, 三上隆
    構造工学論文集 A, 47A, 1, 1, 8, 2001年03月, [査読有り]
    日本語
  • Modeling of Submerged Floating Tunnel as a beam on elastic foundation under bending vibration
    M Sato, S Kanie, T Mikami, T Yaginuma, H Hamaguchi
    STRAIT CROSSINGS 2001, 535, 540, A A BALKEMA PUBLISHERS, 2001年, [査読有り]
    英語, 研究論文(国際会議プロシーディングス), This paper presents a modeling for simplified analysis of the global dynamic behaviors of Submerged Floating Tunnel (S.F.T.). The simple model that we proposed is a beam on elastic foundation. In static problems, it is known that this modeling of S.F.T as a beam on elastic foundation is applicable only to a limited range of support stiffness, spacing and flexural rigidity of the tunnel. However it should be verified that the modeling is applicable also for dynamic response analysis. In this study we investigate the applicability of this modeling in dynamic problems. As a result, we conclude that dynamic effect has no influence on equivalence and the modeling proposed in this study is useful even for dynamic problems.
  • 水中浮遊式トンネルの初期構造設計法に関する一考察
    佐藤 太裕, 横濱 秀明, 蟹江 俊仁, 三上 隆
    海洋開発論文集, 17, 17, 277, 280, Japan Society of Civil Engineers, 2001年, [査読有り]
    This paper is concerned with modeling for simplified analyses of Submerged Floating Tunnel (S. F. T.). The simple model that we proposed is a beam on elastic foundation. It is known that this modeling of S. F. T. as a beam on elastic foundation is applicable only to a limited range of support stiffness, spacing and flexural rigidity of the tunnel from the aspect of structural mechanics. If this modeling gives satisfactory solution for global behaviors of the structure, it is very effective for designers to assume structural dimensions and evaluate the basic characteristics quickly. In this paper we investigate the applicability of this modeling in applying the structural conditions and dimensions of really assumed S. F. T. to the condition of equivalence between S. F. T. and beams on elastic foundation. Furthermore, we consider the effects of boundary condition when this beam model on elastic foundation can be applied.
  • 水中浮遊式トンネル解析における等価な弾性床上梁モデルについて
    佐藤太裕, 蟹江俊仁, 三上隆
    構造工学論文集 A, 46A, 1, 41, 49, 2000年03月, [査読有り]
    日本語

その他活動・業績

書籍等出版物

講演・口頭発表等

  • 植物の不思議な形態に学ぶ(マルチスケール)材料力学
    佐藤太裕
    第8回マルチスケール材料力学シンポジウム, 2023年05月28日, 日本語, 口頭発表(招待・特別)
    2023年05月28日 - 2023年05月28日, 11970368, [招待講演]
  • 直立植物のかたちに潜む材料力学的合理性:樹木、竹(など)を例に
    佐藤太裕
    日本材料学会 北海道・東北支部合同材料フォーラム, 2022年03月17日, 日本語, 口頭発表(招待・特別)
    2022年03月17日 - 2022年03月17日, 11970368, [招待講演]
  • 賢い「竹」がもつ構造・材料力学的戦略
    佐藤太裕
    日本塑性加工学会 ポーラス材料分科会 2021年研究討論会「自然界のポーラス構造」, 2021年12月02日, 日本語, 口頭発表(招待・特別)
    2021年12月02日 - 2021年12月02日, 11970368, [招待講演]
  • 「植物」がエンジニアに教えてくれること -植物のかたちの力学的合理性から見えてくるもの-               
    佐藤太裕
    北海道技術者育成プラットフォームシンポジウム, 2021年11月17日, 日本語, 公開講演,セミナー,チュートリアル,講習,講義等
    2021年11月17日, [招待講演]
  • 工学の視点で植物を見る -賢い「竹」が軽さと丈夫さを併せもつ秘密-               
    佐藤太裕
    ナイスステップな研究者2019講演会, 2020年09月08日, 日本語, 公開講演,セミナー,チュートリアル,講習,講義等
    2020年09月08日, [招待講演]
  • 竹が「軽さ」と「丈夫さ」を併せもつ理由の構造・材料力学的解明               
    佐藤太裕
    材料・材料強度・加工懇話会, 2020年02月17日, 日本語, 公開講演,セミナー,チュートリアル,講習,講義等
    [招待講演]
  • 賢い「竹」が生み出す巧みな材料力学的機能の秘密               
    佐藤太裕
    第51回溶融塩化学討論会, 2019年10月24日, 日本語, 口頭発表(招待・特別)
    [招待講演], [国内会議]
  • Learning from bamboo: New mechnical concept of "Plant"-mimetics
    Motohiro Sato
    The 9th East Asia Mechanical and Aerospace Engineering Workshop, 2019年05月30日, 英語, 口頭発表(基調)
    11970368, [招待講演]
  • Learning from bamboo: Plant-mimetic design toward less-material & high-stiffness structure               
    佐藤太裕
    University of Cambridge, Engineering Department Structures Research Seminars, 2017年06月16日, 英語, 公開講演,セミナー,チュートリアル,講習,講義等
    [招待講演]
  • Learning from bamboo: Plant-mimetic design toward less material & high-stiffness structure               
    佐藤太裕
    Joint Seminar on the Application of Nano materials in Civil Engineering, 2016年12月, 英語, 公開講演,セミナー,チュートリアル,講習,講義等
    [招待講演]
  • 構造力学的手法を用いた新しい次世代型構造システムの研究開発               
    佐藤太裕
    北海道コーディネータ・ネットワーク・フォーラム、合同基調報告(平成25年度北海道科学技術奨励賞受賞記念研究報告会), 2014年02月20日, 日本語, 公開講演,セミナー,チュートリアル,講習,講義等
    [招待講演], [国内会議]
  • The past, present and future of the Seikan Tunnel               
    佐藤太裕
    6th International Symposium on Strait Crossings, 2013年06月, 英語, 口頭発表(基調)
    [招待講演], [国際会議]

担当経験のある科目_授業

  • 計算固体力学特論               
    北海道大学大学院工学院
    2021年04月 - 現在
  • 構造力学特論               
    北海道大学大学院工学院
    2020年 - 現在
  • 材料力学Ⅰ               
    北海道大学工学部機械知能工学科
    2019年 - 現在
  • 寒冷地構造力学特論               
    北海道大学大学院工学院
  • 物理学実験               
    北海道大学教養部
  • 応用数学演習Ⅱ               
    北海道大学工学部
  • 構造解析学               
    北海道大学工学部
  • 構造力学演習Ⅱ               
    北海道大学工学部
  • 構造力学Ⅱ               
    北海道大学工学部
  • 構造力学演習Ⅰ               
    北海道大学工学部
  • 構造力学I               
    北海道大学工学部

所属学協会

  • 2021年04月 - 現在
    日本材料学会               
  • 日本機械学会               
  • 日本計算工学会               
  • 土木学会               

共同研究・競争的資金等の研究課題

  • 積雪期の交通安全を脅かす「そろばん道路」の発生機序解明と予知システムの開発
    科学研究費助成事業
    2024年04月01日 - 2028年03月31日
    島 弘幸, 佐藤 太裕, 梅野 宜崇
    日本学術振興会, 基盤研究(B), 山梨大学, 24K01111
  • プラントニックデザイン:植物の力学 的戦略に内在する構造設計指導原理の 発見と利用               
    一般研究助成
    2024年04月 - 2025年03月
    鹿島財団, 研究代表者
  • 竹林資源の高度利用技術開発:工学・農学・化学3方向からのアプローチ               
    環境研究助成
    2023年11月 - 2024年11月
    住友財団, 一般研究, 研究代表者
  • 空間周期性の構造安定論的解釈と合理化社会・構造システム設計思想のパラダイムシフト
    科学研究費助成事業(基盤研究(A))
    2018年04月 - 2023年03月
    佐藤太裕
    文部科学省, 研究代表者, 競争的資金
  • 竹の優れた機能に関する経験知・言い伝えの理論的解釈と新しい竹林資源利用技術の開発
    科学研究費助成事業(基盤研究(B)(特設分野研究))
    2018年07月 - 2021年03月
    佐藤太裕
    文部科学省, 研究代表者, 競争的資金
  • 車両走行により自然発生する路面凹凸パターン:安全性向上に向けた科学的形成機構解明
    科学研究費助成事業
    2016年04月01日 - 2019年03月31日
    蟹江 俊仁, 佐藤 太裕, 島 弘幸, 金田 安弘, 永田 泰浩, 正木 智
    理論・実験・実地観測という3つのアプローチによる理論と立証の繰返しにより、凹凸パターンの静的分布形態や動的成長過程を含めた形成機構の科学的解明に取り組んだ。特に路面材料については、砂、粘土、粒状体、人工雪など様々な素材を適用し、その湿潤度や密度、温度条件等を変化させながら、形成機構に関わる影響因子の特定や、数理・物理モデルに基づく予測・制御方法の提案を試みた。
    その結果、パターン形成問題についての物理的な面からの現象説明は大きく進んだものと考えている。また積雪凍結路面に発生するそろばん道路についても、発現の予測や予報も可能となり、今後の道路管理に必要な情報提供が可能なレベルに到達した。
    日本学術振興会, 基盤研究(C), 北海道大学, 16K01278
  • ナノ技術および生物科学の積極導入による新しい多重機能型構造システムの研究開発(国際共同研究強化)               
    科学研究費助成事業(国際共同研究加速基金(国際共同研究強化))
    2016年04月 - 2019年03月
    佐藤太裕
    文部科学省, 研究代表者, 競争的資金
  • 自然界における周期性の自発的パターン形成機構解明と社会システム設計への合理的応用               
    科学研究費助成事業(挑戦的萌芽研究)
    2016年04月 - 2018年03月
    佐藤太裕
    文部科学省, 研究代表者, 競争的資金
  • ナノ技術および生物科学の積極導入による新しい多重機能型構造システムの研究開発
    科学研究費補助金(基盤研究(B))
    2015年04月 - 2018年03月
    佐藤 太裕
    本研究はナノ技術および生物科学的知見を積極的に導入することにより、既存の概念にとらわれない卓越した多重機能を有する構造材料、構造システムの提案を行うことを大きな目的とするものである。具体的には「カーボンナノチューブ」に代表されるナノスケール炭素繊維の形状変形性能と、それに伴う電子状態変化を積極利用した新しい構造システムや、竹を例に植物が長年の進化の過程で獲得した力学的に最適な形態の模倣技術を活かした構造設計技術の新規提案を行ったものである.
    文部科学省, 基盤研究(B), 北海道大学, 研究代表者, 競争的資金, 15H04207
  • 竹の節と組織構造に学ぶ合理的な構造システムの設計技術開発               
    研究助成金
    2016年04月 - 2017年03月
    佐藤太裕
    寿原記念財団, 研究代表者, 競争的資金
  • 人工凍結を利用した「高靱性」パイプインパイプの実用化開発
    科学研究費助成事業
    2013年04月01日 - 2016年03月31日
    蟹江 俊仁, 佐藤 太裕
    人工凍結を利用したパイプインパイプは、既存材料を使いながらも、弾性域から塑性域まで滑らかな曲げ変形挙動を示し、高い靱性を発揮するものである。本研究の結果、大きな曲げ変形挙動まで追える実験装置の改良が施され、画像処理による変形計測方法の導入により、その変形挙動が仔細に把握できた。実験結果は、中詰材料の特性を反映した靱性の向上を示しており、特に人工凍結させた供試体では、著しい性能の改善が見られた。このような現象を物理的に説明するためのモデル構築にも取り組み、適切なモデルの提案がなされた。これらの成果により、人工凍結を利用した高靱性パイプインパイプの実用化は大きく前進したものと考える。
    日本学術振興会, 基盤研究(C), 北海道大学, 25420473
  • 悪路で自然発生する波状起伏の機構解明とそれに基づく道路管理技術の新構築
    科学研究費補助金(挑戦的萌芽研究)
    2014年04月 - 2016年03月
    佐藤 太裕
    本研究では自動車が走行した際に未舗装路に生じる「波状起伏現象」、および積雪・凍結路面特有のこぶ状の起伏、いわゆる「そろばん道路」について、その発生メカニズムを独自に考案した科学的アプローチにより解明することを目的とした挑戦的研究である。実験・理論・計測の三方向から現象の根源に迫り、成果報告書に後述するいくつかの興味深い知見を得ることができた。
    文部科学省, 挑戦的萌芽研究, 北海道大学, 研究代表者, 競争的資金, 26560160
  • 剛・柔の効果的組合せにより高靭性・応力集中低減を実現する革新的海洋構造技術の開発
    科学研究費補助金(若手研究(A))
    2012年04月 - 2015年03月
    佐藤 太裕
    本研究は、海洋構造物、社会基盤構造物等に広く用いられる既存の構造材料、複合構造の概念を大きく覆す、「剛・柔材料を効果的に組み合わせることにより高靭性・応力集中の低減を容易に実現可能な、ナノテクの知見を応用した新しい発想に基づく構造システム」の研究開発を目的とするものである。初年度である平成24年度に得られた研究成果を以下に列挙する。(1)剛・柔の簡易な二次元規則積層構造モデルを構築し、定式化を行った。その結果、柔層の存在しない構造に対して剛・柔の規則積層構造は亀裂進展に対する応力集中低減効果があることが解析的に確認された。(2)他媒体に埋め込んだカーボンナノチューブの機能を解析的に検証した。具体的には他媒体との相互作用による外圧印加時のカーボンナノチューブの力学的性質の変化を、分子動力学モデルおよび連続弾性体モデルを構築し、両モデルに対して座屈変形解析を実施した。その結果外圧印加の状態や多層化などによりいくつかの特異な幾何形状の変化がみられ、それによる導電性変化の可能性が見出された。分子動力学解析においては大変形の解析を正確に行うことができ、連続体モデルでは計算負荷の少ない解析を行えることから、双方の利点を活かした諸特性の検証が可能となった。(3)高靱性パイプとして期待されるパイプインパイプの曲げ挙動について、断面偏平の観点から検証し、塑性領域での高靱性化に提案する砂粒子コア材の有用性を確認した。
    文部科学省, 若手研究(A), 北海道大学, 研究代表者, 競争的資金, 24686096
  • 極微スケール炭素繊維を用いた高機能構造材料開発を可能にする革新的マルチスケール構造解析技術の開発               
    研究助成金
    2013年04月 - 2014年03月
    佐藤太裕
    寿原記念財団, 研究代表者, 競争的資金
  • 水中係留浮体の構造挙動を積極活用した新しい発電・防災兼用システムの研究開発
    科学研究費補助金(挑戦的萌芽研究)
    2012年 - 2013年
    佐藤 太裕
    現在世界を取り巻く地球環境の悪化、およびそれに伴う甚大な自然災害問題は、人類が取り組むべき喫緊の最重要課題の一つである。本研究は将来的な環境保全技術として、係留索を用いて水中に安定化させる水中係留浮体構造の「動揺しやすい」性質を積極活用することでエネルギーを得るとともに、波浪・災害から陸地を守るという二重の機能を有した革新的次世代洋上施設の技術成立性について多角的に検討することを本研究期間の目的としている。初年度である平成24年度は、国内外の海洋エネルギー、防災施設に関する調査を実施するとともに、構造力学的観点から以下の課題に取り組んだ。得られた知見を以下に示す。(1)水中係留浮体構造解析モデルの検証:浮体部を質点系としてモデル化し、係留索のゆるみ(スラック状態)を考慮可能な解析モデルを構築した。(2)上記解析モデルによる大波浪の作用による非線形動的挙動の時刻歴計算:上記の解析モデルを用い、波浪入射時の構造挙動の時刻歴解析を実施し、大波浪時のスラック状態と係留索の急激な張力回復に伴い生じる準衝撃的な力(スナップ荷重)の発生メカニズムを再現した。(3)浮体を円筒シェルとした場合のモデル構築:構造挙動は係留索配置の状態とともに、浮体と浮体をジョイントする部分の剛性や浮体自身の弾性も大きく影響することから、これらに関するモデル化と、その基本的な構造特性について差分方程式を用いたモデルを構築し、検討を行った。
    文部科学省, 挑戦的萌芽研究, 北海道大学, 研究代表者, 競争的資金, 24651183
  • 曲げ特性を容易に制御可能とする新しいフレキシブルパイプインパイプの研究開発
    科学研究費補助金(若手研究(B))
    2009年04月 - 2012年03月
    佐藤 太裕
    本研究は、二重管パイプの間に中詰コアとして砂などの粒状体材料を挿入することにより高靭性を発揮し、かつ中詰コアの物性を変化させることにより曲げ特性を容易に制御可能とする、新しい「フレキシブルパイプインパイプ」の開発を行うことを目的としたものである。研究期間内に理論的、実験的両面から多角的な検討が行われ、本提案形式の優位性が実証された。
    文部科学省, 若手研究(B), 北海道大学, 研究代表者, 競争的資金, 21760662
  • 「環境変化順応型」冷却ガスパイプライン技術の開発~複合材料利用による新しい可能性
    科学研究費補助金(基盤研究(B))
    2008年04月 - 2011年03月
    蟹江 俊仁, 赤川 敏, 三上 隆, 岩花 剛, 佐藤 太裕, 赤川 敏
    天然ガス資源に恵まれる北方寒冷地域を対象に,冷却ガスパイプラインの新しい構造形式として,中詰材に砂などの可塑性材料を用いるパイプインパイプの開発を行なった.特に中詰材に水を飽和させ凍結することで,より高い靭性が発揮され,材料の非線形領域まで有効に利用できるため,周辺環境の変化に対しても柔軟に対応できる.さらに,周辺土の凍結・融解を人為的に制御することで,曲げ剛性の回復や漏洩防止も可能となった.
    文部科学省, 基盤研究(B), 北海道大学, 連携研究者, 競争的資金, 20360196
  • チューブ状構造の複雑な変形挙動に関する構造力学的研究~ナノからマクロスケールまでを包含する新しい力学的数理モデルの構築~               
    若手教員在外研究助成
    2010年 - 2011年
    佐藤太裕
    北海道大学大学院工学研究科, 研究代表者, 競争的資金
  • 二重管構造の採用による埋設配管の応力集中回避性能に関する解析的検討               
    大学助成制度
    2010年 - 2011年
    佐藤太裕
    北海道ガス, 研究代表者, 競争的資金
  • ナノ構造体の優れた力学特性を利用した新しい高強度構造材料の創製               
    重点配分経費(若手研究者自立支援)
    2009年 - 2010年
    佐藤太裕
    北海道大学, 研究代表者, 競争的資金
  • 災害安全性の高い埋設配管構造技術とその構造力学的特性に関する研究               
    大学助成制度
    2009年 - 2010年
    佐藤太裕
    北海道ガス, 研究代表者, 競争的資金
  • 海洋パイプラインの複雑な挙動解析に適した新規な構造解析モデルの理論的構築
    科学研究費補助金(若手研究(B))
    2006年04月 - 2009年03月
    佐藤 太裕
    海洋パイプラインは、大水深域での極めて大きな静水圧作用など、厳しい海洋環境下でも安定したエネルギー輸送が要求される構造物である。本研究はこの要求性能を高い次元で満足し、かつ構造設計の自由度が大きい海洋パイプラインとして現在世界的に注目されている「パイプインパイプシステム」について、その構造設計に関わる構造解析モデルの構築と、構造挙動の把握を行ったものである。
    文部科学省, 若手研究(B), 北海道大学, 研究代表者, 競争的資金, 18760615
  • パイプインパイプ構造における曲げ挙動評価システムの構築               
    大学助成制度
    2008年 - 2009年
    佐藤太裕
    北海道ガス, 研究代表者, 競争的資金
  • 寒冷地道路トンネルの建設コスト縮減を意図した支保構造設計法の提案
    科学研究費補助金(基盤研究(B))
    2004年04月 - 2007年03月
    三上 隆, 須藤 敦史, 佐藤 京, 蟹江 俊仁, 佐藤 太裕
    トンネルの支保構造物の設計は、その多くを過去の経験に基づく設計法によるため、ややもすると地上のコンクリート構造物の設計に比べて過大な設計になりがちである。本研究では、設計段階における建設コスト縮減を意図し、さらに寒冷地特有の諸条件を加味した道路トンネルの支保構造設計法の提案を目的に行ったもので、主な成果は以下となる。1.支保工特性曲線の提案:円筒殻理論(吹き付けコンクリート)及びリング理論(鋼アーチ支保工)に基づき、両者の相互作用を考慮した解析モデルより、支保剛性評価式を提示した。主な結果は以下となる。(1)リング理論による従来法の支保剛性は、本算定式による支保剛性より常に大き目の評価をし、その差は最大で20%程度である。(2)鋼製アーチ支保の有効支保間隔は、鋼製アーチ支保間隔をLと記せば、(0.35〜1)Lである。2.トンネル延長方向の温度(気温)算定式の提案:寒冷地トンネルでは、寒さに起因する変状を防止するために、断熱材が施工されるが、その合理的な施工のためにはトンネル延長方向の温度分布が必要となる。ここでは、トンネル-地山系の熱伝達・熱伝導及びトンネル内風速を考慮した解析的モデルに基づき、温度評価式を求めた。(1)本算定式より得られるトンネル延長方向の温度及び道内トンネルの実測値との比較によれば、両者には良好な一致が認められ、本算定式の有効性・妥当性が確認された。(2)その結果、本算定式によれば、トンネル坑口からの断熱材の施工範囲が合理的に決定できる。
    文部科学省, 基盤研究(B), 北海道大学, 連携研究者, 競争的資金, 16360221
  • 係留浮体式風力発電システムの技術成立性に関する調査研究               
    研究助成(電気・エネルギー一般研究)
    2006年 - 2007年
    佐藤太裕
    (財)東電記念科学技術研究所, 研究代表者, 競争的資金
  • 水中浮遊式トンネルの実現に向けた動的不安定問題の解明               
    研究者海外派遣援助(長期)
    2005年 - 2006年
    佐藤太裕
    鹿島学術振興財団, 研究代表者, 競争的資金
  • 水中浮遊式トンネルにおける動的不安定挙動発生機構の解明               
    基礎的研究開発育成事業(若手研究補助金)
    2004年 - 2005年
    佐藤太裕
    ノーステック財団, 研究代表者, 競争的資金
  • 微生物を利用した再生骨材の製造とその品質に関する研究
    科学研究費補助金(萌芽研究)
    2003年 - 2004年
    角田 與史雄, 佐藤 太裕, 佐藤 太裕, 松村 宇, 伊藤 正澄, 佐藤 靖彦
    本研究は,バクテリアリーチングにおいて利用されてきた方法を基本とし,微生物を利用して再生骨材を製造し,その品質を明らかにすることで,再生骨材の製造に微生物を利用することの有用性を示そうとするものである.本研究において,多種多様な微生物の中から硫黄酸化細菌と鉄酸化細菌に着目した基礎実験を行った.すなわち,細菌の有無,骨材の有無,コンクリート塊の大きさ,炭酸化の有無がペースト及びモルタルの劣化度に及ぼす影響を実験的に明らかにした.得られた知見を以下に列挙する.・硫黄酸化細菌及び鉄酸化細菌が増加すると培地のPHを低下させ,モルタルをよく剥離させ,カルシウムイオンを溶脱させる.・硫黄酸化細菌と鉄酸化細菌の活動は,コンクリート塊のサイズが5-20mmの範囲の方が,5mm以下の範囲よりも活発化した.これは塊のサイズが小さいと培地に溶け出すアルカリ量が多くなるためである.それゆえ,微生物を摂取する前に炭酸化させた方が良い.・硫黄酸化細菌と鉄酸化細菌が骨材に及ぼす影響は工学的に無視できる.・酸性硫黄温泉水を培地として利用した場合,効率よくカルシウムイオンを遊離させることができる.しかし,コンクリート塊の表面に生成される腐食性生物が硫酸イオンの浸透を阻止する為,反応速度が著しく低下する.
    文部科学省, 萌芽研究, 北海道大学, 研究代表者, 競争的資金, 15656103

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