Nonlinear fracture mechanics analyses considering the material nonuniformities in and the vicinities of welded joints
| Project/Area Number |
16K05988
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
Okada Hiroshi 東京理科大学, 理工学部機械工学科, 教授 (50281738)
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| Co-Investigator(Kenkyū-buntansha) |
遊佐 泰紀 東京理科大学, 理工学部機械工学科, 助教 (70756395)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2016: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | 非線形破壊力学 / 溶接接手 / J積分 / 応力拡大係数 / 相互積分法 / 有限要素法 / 溶接継手 / 破壊力学 / 重合メッシュ法 / 傾斜機能材料 / 破壊 |
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| Outline of Final Research Achievements |
The failures of welded structures, in many cases, initiate from their welded joints and their vicinities. The weld processes generate the weld residual stresses. The material properties may vary in the joints and their vicinities due to the complex temperature and deformation histories. In the past, many fracture mechanics methodologies have been developed for homogeneous materials. In order for us to apply them to the fracture evaluations of cracks in and in the vicinity of welded joints, the fracture mechanics methodologies need certain extensions. In the present investigation, we successfully developed new J-integral formulations for infinitesimally small deformation and for finite deformation problems with spatially varying mechanical properties. Furthermore, an iterative s-Version Finite Element Method for material and geometrical nonlinear problems was proposed in the investigation.
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| Academic Significance and Societal Importance of the Research Achievements |
発電プラント構造物や機器，船舶，橋梁等，社会的に重要なインフラ構造物の多くが溶接構造物である．溶接構造物の多くで溶接継手とその近傍が破壊の起点である．そのため，溶接継手とその周辺から発生する疲労き裂の力学的評価は大変重要な課題である．本研究では，溶接継手とその周辺のき裂損傷に対する破壊力学評価手法の高度化と体系化により，学術的貢献をするとともに，社会的に重要なインフラ構造物の安全性と信頼性向上に寄与するものである．本研究では，破壊力学解析手法として，J積分法や相互積分法の高度化に成功し，溶接欠陥の簡便なモデル化のために反復型重合メッシュ法による材料・幾何学的非線形解析を提案した．
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Report
(4 results)
Research Products
(22 results)
