{"created":"2021-03-01T06:51:31.679317+00:00","id":32813,"links":{},"metadata":{"_buckets":{"deposit":"a5245e68-1cd8-4336-a7d1-0a35460a2e3e"},"_deposit":{"id":"32813","owner":"1","owners":[],"pid":{"revision_id":0,"type":"depid","value":"32813"},"status":"published"},"_oai":{"id":"oai:repository.dl.itc.u-tokyo.ac.jp:00032813","sets":["80:4535:4747:4748","9:504:4538:4749:4750"]},"author_link":["127744","127745","127742","127743"],"item_4_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"Fracture Analyses of Concrete Structures by Granular Assembly Simulation"}]},"item_4_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1989-03-31","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"4","bibliographicPageEnd":"468","bibliographicPageStart":"409","bibliographicVolumeNumber":"63","bibliographic_titles":[{"bibliographic_title":"東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo"}]}]},"item_4_description_13":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_4_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"本研究は,非連続体解析法を用いたコンクリートの破壊解析手法を,提案するものである.従来,コンクリートの破壊解析は,主として媒質を均質な連続体と近似して取扱う,有限要素法(FEM)や境界要素法(BEM)などの連続体解析法を用いて行われてきた.しかし,これらの手法は,解析対象物に破壊が発生するまでの解析を主眼とするものであり,破壊発生後の挙動や大変形問題等の解析には,多くの困難を伴う.また,コンクリートの媒質は鋼などに比べて不均質であり,骨材とモルタルという物性の違う物質から成る混合体である.破壊の強度や形状は,コンクリート中の骨材の強度や粒度,その量や分布の影響を受け,更にモルタルの性質によって変化する.媒質を均質な弾性体と近似して取り扱う従来の連続体解析法を用いて,これらの現象をうまく説明することは困難である.これらの現象をうまく表現できる解析手法を提案することは,現在のコンクリートの破壊解析における,1つの大きな課題であると考えられる.ところで最近,電子計算機の計算速度の高速化と記憶容量の巨大化を背景として,解析対象物の媒質を小要素の集合体として取扱う非連続体解析法が,盛んに行なわれるようになってきた.この手法の一つに,Cundallによる個別要素法(Distinct ElementMethod, DEM)があり,先駆的なものとして知られている.しかし,主として土(地盤,石,岩盤を含む)を対象として進められてきた従来のDEM理論では,コンクリートの挙動をうまく表現する事は難しかった.それは従来のDEMでは,骨材をとり囲むモルタルの効果が考慮されていなかったからである.DEM解析において,要素の間隙を埋める物質の力学的モデル化についての研究は,間隙水の効果に関する研究,間隙の粘性土に関する研究等があるが,これらは,モルタルの挙動を表現するモデルとしては適当ではない.そこで本研究では,コンクリートにも対応できる非連続体解析手法として,改良個別要素法(Modified Distinct Element Method, MDEM)を開発し,実際にコンクリートの破壊解析に適用した.MDEMにおいてコンクリート中の粗骨材は円形要素として,モルタルは非線形なバネとして,それぞれ表現した.MDEMでは,媒質を独立した小要素の集合体と考えるので,材料の不均一性も要素のばらつきという形で考慮できる.MDEMは,大変形問題や破壊発生までの解析に加えて,破壊の進行過程までの一連の解析が可能であり,連続体解析法の欠点を補える.また,滑り面の形成やダイレタンシーの効果等が自然と表現される特徴を持つ.更に,巨視的な観点からの破壊モードの解析に加え,個々の骨材間の微視的破壊のメカニズムまで追跡することができる等の点で優れている.ケース・スタディーとして,コンクリート供試体を用いた破壊試験のシミュレーションと,コンクリート構造物の動的破壊解析を行なった.解析結果は,従来の室内実験結果,あるいは地震被害と調和的なものであり,またMDEMならではの見解も得られた.これらの結果から,改良個別要素法(MDEM)が,コンクリートの破壊解析法として有効である事が確認された.","subitem_description_type":"Abstract"},{"subitem_description":"A new fracture analysis method of concrete structures is proposed in which concrete is considered a granular assembly. A number of fracture analyses of concrete structures have been made by the finite element method (FFM) in which concrete has been considered a homogeneous and continuous material. But concrete is a complex and extremely heterogeneneous material, it is difficult to analyze its fracture properties by using FEM. On the other hand, the distinct element method (DEM), in which medium has been treated as an aggregation of individuall small elements, has been studied in geotechnical engineering. But the conventional DEM is hardly applicable to the concrete structures because the effect of mortar surrounding gravels has not been considered in this method. We have developed a modified distinct element method (MDEM), and have applied it newly to fracture problems of concrete structures which had not been solved by the conventional DEM. In MDEM, two major constituents of concrete, gravels and mortar, are represented respectively as circular particle elements and nonlinear springs. The heterogeneity of material can be taken into consideration as dispersion of particle elements. This method, MDEM, can follow the total fracture process even after discontinuity of the medium occurs. Nonlinear phenomena such as shear band and the influence of dilatancy are simulated automatically. Not only the overall mode of fracture but also the microscopic fracture mechanism of individual elements are obtained. This newly proposed method, MDEM, is applied to simulate the dynamic fracture behaviors of concrete structures. Numerical results obtained in this study agree well with laboratory tests as well as seismic damages observed during past earthquakes.","subitem_description_type":"Abstract"}]},"item_4_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"127744","nameIdentifierScheme":"WEKO"}],"names":[{"name":"Meguro, Kimio"}]},{"nameIdentifiers":[{"nameIdentifier":"127745","nameIdentifierScheme":"WEKO"}],"names":[{"name":"Hakuno, Motohiko"}]}]},"item_4_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15083/0000032813","subitem_identifier_reg_type":"JaLC"}]},"item_4_publisher_20":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"東京大学地震研究所"}]},"item_4_source_id_10":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN00162258","subitem_source_identifier_type":"NCID"}]},"item_4_source_id_8":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"00408972","subitem_source_identifier_type":"ISSN"}]},"item_4_subject_15":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"453","subitem_subject_scheme":"NDC"}]},"item_4_text_21":{"attribute_name":"出版者別名","attribute_value_mlt":[{"subitem_text_value":"Earthquake Research Institute, University of Tokyo"}]},"item_4_text_4":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"東京大学大学院"},{"subitem_text_value":"東京大学地震研究所"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"目黒, 公郎"}],"nameIdentifiers":[{"nameIdentifier":"127742","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"伯野, 元彦"}],"nameIdentifiers":[{"nameIdentifier":"127743","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-06-26"}],"displaytype":"detail","filename":"ji0634003.pdf","filesize":[{"value":"4.0 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"ji0634003.pdf","url":"https://repository.dl.itc.u-tokyo.ac.jp/record/32813/files/ji0634003.pdf"},"version_id":"a094fc7d-782c-4d48-89a0-16423c9e30bc"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"粒状体シミュレーションによるコンクリート構造の破壊解析","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"粒状体シミュレーションによるコンクリート構造の破壊解析","subitem_title_language":"ja"}]},"item_type_id":"4","owner":"1","path":["4748","4750"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-05-30"},"publish_date":"2008-05-30","publish_status":"0","recid":"32813","relation_version_is_last":true,"title":["粒状体シミュレーションによるコンクリート構造の破壊解析"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-12-19T04:08:44.590594+00:00"}