| Project/Area Number |
16360226
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural engineering/Earthquake engineering/Maintenance management engineering
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| Research Institution | Kanazawa University |
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Principal Investigator |
YATOMI Chikayoshi Department of Civil Engineering, Professor, 自然科学研究科, 教授 (90135541)
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| Co-Investigator(Kenkyū-buntansha) |
鱸 洋一 五大開発株式会社, 技術研究所, 研究員
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥5,900,000 (Direct Cost: ¥5,900,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2004: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Extended Finite Element Method / Fracture Mechanics / Crack Extension / Compressive Loads / Friction material / Elastic-plastic / Implicit method / Return mapping / 破壊進展 / せん断帯 / 有限変形理論 / 乗法分解 / Cam-clayモデル / X-FEM / ニュートン・ラフソン法 / 亀裂 / 不連続面 / 接触問題 / クーロンの摩擦則 |
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| Research Abstract |
Extended finite element method (X-FEM) was first developed by Belytcheko et al. in 1996 for the linear elastic fracture mechanics to avoid awkward remeshing near a crack tip as the crack grows. The key idea of the extended finite element method is that the unknown variables of discontinuous displacement are added to the nodal continuous displacements so that the crack can extend across the element. The method was, however, restricted only to the cracks in the linear elastic material.
With the aim of analyzing the fracture of geomaterials, we develop a new extended finite element method(X-FEM) available to an elastic-plastic material. We analyzes the stress distributions near a crack tip for the Drucker-Prager elastic-plastic material in a rectangular plate with a centered crack under two axial compressive loads. The elastic-plastic material is analyzed by the implicit return mapping algorithm, which gives a high accuracy and much reduces CPU time by using an incremental and iterative method of the Newton-Raphson method.
Under the compressive loads there exist friction forces along the crack faces. In solving this contact problem, we introduce a new method which conform to the extended finite element method. The friction forces are assumed to follow the elastic-perfect plastic material with Coulomb law for the slip criterion. The friction problem is also analyzed in the context of an implicit return mapping algorithm.
Thus the contact problem and the elastic-plastic material become a simultaneous combining incremental and iterative method of the same implicit scheme of the Newton-Raphson method. This makes the algorithm very simple.
The stress distributions near the crack tip obtained by the simple X-FEM agree very well with the reliable solutions in the classical FEM solution for the elastic-plastic material. For the future, therefore, we anticipate a practical application of this new method such as a land slide.
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