2018 Fiscal Year Final Research Report
Determination of model parameters for 3D DEM using soil values of Bekker's method
| Project/Area Number |
16K07970
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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 |
Agricultural environmental engineering/Agricultural information engineering
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | テラメカニックス / 離散要素法 / 要素形状 / 圧力沈下関係 / せん断応力せん断変位関係 |
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| Outline of Final Research Achievements |
The discrete element method (DEM) is widely used in soil-machine contact problems. In this study, the parameter of contact model in DEM was calibrated by applying the soil values obtained from pressure-sinkage and shear stress-shear displacement relationships in Bekker’s approach. For dry sand condition, particle model consisting of three spheres in series (MSM-L3 model) were manufactured and used in experiments. It could be confirmed that 3D DEM analysis by YADE using MSM-L3 model showed similar values of Bekker’s parameters obtained from the experiments. In case of we cohesive soil, since the measurement of shear stress using annulus ring shear ring resulted in such irrational behavior of cohesion and internal friction angle against moisture content of soil which was , the detailed investigation such as construction of precise cohesive force model for DEM and parametric analysis of Bekker’s parameters against moisture content could not be realized.
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| Free Research Field |
農業機械学
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| Academic Significance and Societal Importance of the Research Achievements |
農用タイヤや履帯と土との接触問題は，土の持つ粒としての性質を考慮した離散要素法が近年よく用いられる．この手法では，土のモデルとしては土粒子自体の大きさよりも大きい仮想粒子をモデルとして解析する．この際に，土粒子モデルの接触力を精度よく表現するため，モデルパラメータを何らかの手法で求める必要がある．本研究では，Bekker法で知られている半経験的手法で採用されているBekkerパラメータに着目し，実験と数値解析で同じ粒子モデルを用いてパラメータを決定する方法を試みた．乾燥砂については概ね妥当な結果が得られたことから，今後の接触問題の数値解析の高精度化に役立つ可能性が高い．
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