著者

宮村 倫司

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.17-00070-17-00070, 2017 (Released:2017-08-25)

参考文献数

24

被引用文献数

1

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The balancing domain decomposition (BDD) method is an effective preconditioner for the substructuring-based iterative solver, which is a kind of the domain decomposition method. The BDD method is a powerful tool for the large-scale implicit structural analysis using the finite element method. It is a kind of the multi-grid method whose coarse grid is defined by the null spaces in subdomain problems. Shioya et al. proposed a method to construct the null spaces for the structural analysis using the rigid body modes of each subdomain. In the present study, the Shioya's method is improved, that is, the rigid body modes are defined using a local coordinate system of each subdomain instead of using the global coordinate system. In the original method, components with very different values are contained in the prolongation and restriction matrices that are used for making the coarse grid stiffness matrix. The proposed method reduces the difference of the values and improves the property of the coarse-grid stiffness matrix. In the numerical experiments, the proposed method reduces computation time and amount of used memory when the coarse grid problem is solved by a sparse direct solver with the pivoting. In addition, the convergence property of the CG method is improved in some numerical examples.

著者

宮村 倫司

出版者

日本大学

雑誌

基盤研究(C)

巻号頁・発行日

2008

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大規模な接触問題解析を実現するために,領域分割法に基づく並列解析手法を開発することが本研究の目的である.最初に,摩擦のない接触問題の解法として, Semismooth Newton法の改良手法,内点法とSemismooth Newton法の組み合わせ手法を提案した.次に,内点法やSemismooth Newton法の反復の中に現れる等式制約条件付線形問題を多点拘束条件を考慮したBDD法で解くためのアルゴリズムの開発について検討した. GPGPU実装による高速化についてもプロトタイプコードを開発した.当初の研究計画には,摩擦のある大規模接触問題の解法の開発が含まれていたが,基礎的な検討にとどまり,研究期間内に実用的な手法を開発することはできなかった.

著者

宮村 倫司 半谷 裕彦

出版者

日本建築学会

雑誌

日本建築学会構造系論文集 (ISSN:13404202)

巻号頁・発行日

vol.62, no.494, pp.91-98, 1997

被引用文献数

2 3

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In this paper finite element analyses of wrinkling on membranes are carried out, and the results are compared with the results of our experiments. An illustrative example is stretched circular membrane under inplane torsion, which is a classical problem in the study of wrinkling. Wrinkling is considered as a bifurcation phenomenon. It is analyzed by using four-node membrane finite elements considering geometrical nonlineality. Both isotropic and orthotropic membranes are treated. Membranes are assumed to be elastic. Formulation of the element, a method of introducing initial stresses and a method of bifurcation analysis are shown. First computations for several kinds of shear modulus are carried out and shapes of wrinkles and stress fields are compared. Second computations corresponding to the experiments are carried out. Principal stresses in wrinkling fields and shapes of wrinkles obtained by the analyses and the experiments show good agreement. However, details of the shapes are a little different, since in the analyses the fineness of a finite element mesh is not sufficient.