著者

岡 正徳 都井 裕

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集A編 (ISSN:18848338)

巻号頁・発行日

vol.79, no.806, pp.1411-1421, 2013 (Released:2013-10-25)

参考文献数

18

被引用文献数

1 1

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The elasto-viscoplastic-creep constitutive equation based on the concept of continuum damage mechanics is formulated for the gray cast iron as used in diesel engine parts. It employs the viscoplastic strain given by Chaboche-Rousselier and the creep strain given by Perrin and Hayhurst. A part of the material parameters contained in the creep constitutive equation which was previously identified by Oka and Toi are assumed to be temperature-dependent in the present study. The identified model is applied to the creep fatigue life prediction of the cylinder head used in diesel engine parts which is made of gray cast iron. Although there are some points to be improved, the validity of the proposed model is illustrated by comparing the calculated results with the experimental results for the crack initiation locations and the crack propagation directions.

著者

田中 英紀 都井 裕 前田 一成 酒井 貴洋

出版者

日本学術会議 「機械工学委員会・土木工学・建築学委員会合同IUTAM分科会」

雑誌

理論応用力学講演会 講演論文集 第54回理論応用力学講演会 講演論文集

巻号頁・発行日

pp.117, 2005 (Released:2005-04-08)

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コンクリートの損傷破壊挙動に対し、Drucker-Pragerの降伏条件を用いた弾塑性損傷構成式を定式化し、2次元有限要素解析プログラムにインプリメントした。コンクリートの材料試験結果から構成式中のパラメータを決定し、コンクリート構造要素の破壊挙動の有限要素解析を実施した。さらに、解析結果と実験結果の対応について考察した。

著者

広瀬 智史 都井 裕

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.852, pp.17-00130-17-00130, 2017 (Released:2017-08-25)

参考文献数

23

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A discontinuous material behavior such as ductile fracture and fatigue failure is predicted actively in various fields by FEM. There is continuum damage mechanics as a method to evaluate the discontinuous material behavior in a framework of continuum mechanics. However, the predicted behavior based on the method depends strongly on finite element size. Then, improvement of damage evolution equation and damage limit equation in continuum damage mechanics is discussed to reduce the mesh-dependence. These equations are extended based on finite element size and evaluated strain gradient. The predicted material property such as fracture strain in tensile test based on new equations corresponds to experimental result. Additionally, the prediction accuracy is higher than conventional mesh-independence model. Especially, the higher the tensile strength of material is, the higher the prediction accuracy is.

著者

都井 裕 諸正 信

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.59, no.557, pp.240-247, 1993-01-25

被引用文献数

7 3

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Fracture behaviors of brittle polycrystalline solids such as ceramic materials are deeply related to microcracking. Continuum damage mechanics is considered a powerful theoretical framework to deal with brittle microcracking materials, however, it is fairly difficult to obtain analytically as well as experimentally evolution equations for microcracking and reduced elastic compliances of microcracked solids. In the present study, a mesoscopic (grain level) simulation method using a discontiuum mechanics model is proposed to solve these problems. The validity and limitations of the isotropic theory of continuum damage mechanics are studied in the first report.